kth.sePublications
Change search
Refine search result
1234567 1 - 50 of 437
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Akbarpour, Sahar
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures. KTH.
    Enhanced Composite Joint Performance through Interlacement of Metal Inserts2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work in this thesis investigates bolted joints in fibre reinforced composites with particular focus on a novel insert concept. The concept is characterised by replacing all composite plies with stacked metal patches, locally around a bolt hole, so that they jointly form a solid metal reinforcement. An extensive experimental study is presented together with finite element analysis of the studied cases.

    Reinforcing bolt holes with high-strength metals improves the bearing load capacity of the composite laminates. True enhancement of the joint performance however requires that the open-hole tensile strength is improved as well. The work started with tests of pin-loaded and open-hole tensile specimens with inserts, and significant improvement of the bearing load capacity was found. The initial tests enabled more informed design, and insert configurations having sufficient open-hole tensile strength could thereby be manufactured and tested. In parallel, composite-metal joints were numerically modelled to simulate and analyse the mechanical performance of the joints and gain a better understanding of the governing damage mechanisms.

    The performance of the joints was eventually investigated by means of experiments on single-shear, single- and double-bolt specimens, with and without inserts. The allowable bolt distance and the influence from the bolt tightening torque were also examined.

    The initial samples had inserts of stainless steel. Later, specimens with titanium alloy inserts were also included in the test series. Various insert configurations were designed to study the effects of different features in the composite-metal bond lines. The numerical simulations of the composite--metal interfaces were performed with two types of models, one joining the two materials directly to each other, without modelling any adhesive film in between, and the other including an elastic representation of the adhesive layer. The experimental results were then used to support verification of the results from the simulations.

    The final assessment of the concept was performed on insert configurations designed either for pure tensile loading or for more general (bi-directional) loading conditions, and the bearing load capacity, open-hole tensile strength and the performance of bolted joints were compared for cases with different inserts. While higher bearing strength improvement was achieved when the holes were reinforced with inserts of stainless steel, reinforcement with inserts of titanium was even more successful since it improved virtually all studied aspects of the joints considerably.

    Download full text (pdf)
    fulltext
  • 2.
    Akbarpour, Sahar
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Enhancing the performance of bolted joints in composites by use of patched steel or titanium inserts2021In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 275, article id 114464Article in journal (Refereed)
    Abstract [en]

    A new insert concept that interlaces metal inserts into composite laminates has earlier been shown to improve the relatively poor bearing strength of holes in fibre reinforced polymer composites, and it is here further and more thoroughly investigated. The concept was invented to increase the efficiency of joints with mechanical fasteners in composite materials and this work presents experiments on double-bolt joints with inserts made of either stainless steel or a titanium (Ti) alloy. In particular the work compares different implementations of the insert concept by reinforcing one or two holes in double bolt joints, and the effect of using different metals in the inserts. Some complementary tests on pin-loaded specimens and open hole tensile specimens are also performed and compared, partly with results that were reported previously. Considerable improvements of the bearing load capacity are attained, i.e. 50%-60% for steel and 35%-45% for Ti, compared to references. The open-hole tensile strength is also improved considerably (almost 30%) when the holes are reinforced with Ti inserts. The fact that the inserts can improve not only the bearing strength but also the performance in open-hole tension implies that the Ti inserts bring nothing but positive effects to the strength of the joints. The test results from single-shear double-bolt specimens with inserts at one hole showed improved strengths of 30% and 20% for specimens with steel and Ti inserts, respectively. Finally, an impressive strength improvement of 40-45% is achieved for single-shear double-bolt specimens having both holes reinforced with inserts of either steel or Ti.

  • 3.
    Akbarpour, Sahar
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Enhancing the performance of bolted joints in composites by use of patched steel or titanium inserts2021Report (Other academic)
    Abstract [en]

    A new insert concept that interlaces metal inserts into composite laminates has earlier been shown to improve the relatively poor bearing strength of holes in fibre reinforced polymer composites, and it is here further and more thoroughly investigated. The concept was invented to increase the efficiency of joints with mechanical fasteners in composite materials and this work presents experiments on double bolt joints with inserts made of either stainless steel or a titanium (Ti) alloy. In particular the work compares different implementations of the insert concept by reinforcing one or two holes in double bolt joints, and the effect of using different metals in the inserts. Some complementary tests on pin-loaded specimens and open hole tensile specimens are also performed and compared, also with some results reported previously.                    Considerable improvements in the bearing load capacity, i.e. 50%-60% or 35%-45%, is attained. The open-hole tensile strength is also improved considerably (almost 30%)  when the holes are reinforced with Ti inserts. The fact that the inserts can improve not only the bearing strength but also the performance in open-hole tension implies that the Ti inserts bring nothing but positive effects to the strength of the joints. The test results from single-shear double-bolt specimens with inserts at one hole showed improved strengths of 30% and 20% for specimens with steel and Ti inserts, respectively. Finally, an impressive strength improvement of 40-45% is achieved for single-shear double-bolt specimens having both holes reinforced with inserts of either steel or Ti.

  • 4.
    Akbarpour, Sahar
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Experimental investigation and numerical analysis of multi-material interfaces related to a composite joint concept2021Report (Other academic)
    Abstract [en]

    An insert concept for reinforcing bolt-holes with high strength metals was previously introduced by the authors, where inserts are anchored in composite laminates through interlacement of composite plies and thin metal patches. The resulting finger-joints must be strong enough to avoid composite-metal debonding happening before bearing failure at the bolt-hole. The strength of the composite-metal interfaces is thus crucial for successful implementation of the insert concept. The paper presents an experimental study investigating the strength of various interface geometries between a prepreg composite material and stainless steel or titanium alloy inserts. In addition to the experimental work, finite element simulations are performed to analyse the stresses at the interfaces. The results indicate that the stress concentrations at multi-material corner points govern the failure and that the strength can be enhanced by expedient design.

  • 5.
    Akbarpour, Sahar
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Reinforcement around holes in composite materials by use of patched metal inserts2019In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 225, article id 111084Article in journal (Refereed)
    Abstract [en]

    Metal inserts are sometimes used to improve the load carrying capacity of bolted joints in composite materials. In this paper a new concept is introduced where inserts are built during composite manufacturing by integrating stacked metal patches at locations where holes are to be made after consolidation. Initial tests and a parameter study enable more informed design, and specimens with improved stacked inserts are then produced and tested. The specimens with inserts show up to 60% strength improvement in pin-loaded tests. In addition to the experimental work, finite element analysis is performed to investigate the stress fields and the failure mechanisms. The model indicates that the singular stresses at the multi-material corner points are governing for the strength and give indications of the failure mechanisms. Some basic analytical estimates are also presented.

  • 6.
    Akbarpour, Sahar
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Strength improvement of bolted joints in composite materials by use of patched metal inserts2020In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 52, article id 112628Article in journal (Refereed)
    Abstract [en]

    Metal inserts are occasionally used to improve bearing load capacity of bolted joints in laminated composite materials. This paper investigates a new reinforcement concept where inserts are built by locally replacing composite plies with metal patches of various diameters, surrounding the holes. The inserts are built during composite manufacturing by alternately placing the metal patches through the thickness of the laminate at locations where holes are to be drilled after consolidation. An extensive experimental study including pin‐ loaded, open–hole tensile, and single‐shear testing of bolted specimens is presented. Considerable improve- ment of the bearing strength – 50‐60% – is attained for pin‐loaded specimens with inserts, demonstrating the potential of the reinforcement concept. The open–hole tensile tests show that the by‐pass strength can be maintained or even improved with up to 20% if the inserts are properly designed. Finally, the results from the single‐shear tests of bolted joints show more than 25% improvement in strength for reinforced single‐ and double‐bolt specimens. It is possible that the inserts would maintain clamping pressure over time, which could then almost double the imrovement (47%) for bolted joints.

  • 7.
    Alinejadian, Navid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Tallinn Univ Technol, Dept Mech & Ind Engn, Ehitajate Tee 5, EE-19086 Tallinn, Estonia..
    Kazemi, S. H.
    Inst Adv Studies Basic Sci, Dept Chem, Zanjan 4513766731, Iran..
    Grossberg-Kuusk, M.
    Tallinn Univ Technol, Dept Mat & Environm Technol, Ehitajate Tee 5, EE-19086 Tallinn, Estonia..
    Kollo, L.
    Odnevall, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Karolinska Inst, AIMES Ctr Advancement Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, SE-17177 Stockholm, Sweden..
    Prashanth, K. G.
    Tallinn Univ Technol, Dept Mech & Ind Engn, Ehitajate Tee 5, EE-19086 Tallinn, Estonia.;Austrian Acad Sci, Erich Schmid Inst Mat Sci, Jahnstr 12, A-8700 Leoben, Austria.;Vellore Inst Technol, Sch Mech Engn, CBCMT, Vellore 632014, India..
    Importance of the micro-lattice structure of selective laser melting processed Mo/Mo(x)S(x+1) composite: Corrosion studies on the electrochemical performance in aqueous solutions2022In: Materials Today Chemistry, E-ISSN 2468-5194, Vol. 26, article id 101219Article in journal (Refereed)
    Abstract [en]

    Selective laser melting (SLM) based processing of Mo-based samples is challenging due to solidification cracking. We here demonstrate that the addition of 2 wt% MoS2 to the Mo feedstock markedly improves crack mitigation of SLM-processed Mo/MoS2/Mo2S3 composite micro-lattice structures (SLM-Mo/ Mo(x)S(x+1)). Crack inhibition is suggested to be a result of Mo2S3 formation, decreased lattice strain (0.04 4%), and a decrease in accumulated residual stresses. The increased values of polarization resistance from 42.3 and 19.2 kU cm2 to 437 and 78.2 kU cm2, respectively verified the hindering effect of the composition on stress corrosion cracking (SCC) and surface oxidation cracking. However, an increased corrosion current density, from 1.22 to 10.2 mA/cm2, and cathodic Tafel constant, from 175 to 260.5 mV, confirmed the decreased polarization resistance and occurrence of different types of corrosion such as SCC and pitting. The strategy to add 2 wt% MoS2 to the Mo feedstock enables the fabrication of hightemperature micro-lattice structure components with improved corrosion resistance properties applicable in e.g., electronic, power semiconductor heat sinks, offshore-, aerospace-, defense-, or particularly novel sodium-ion energy storage applications.

  • 8.
    Almesmari, Abdulla
    et al.
    Advanced Digital & Additive Manufacturing Center, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788; Department of Mechanical Engineering, School of Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788.
    Baghous, Nareg
    Advanced Digital & Additive Manufacturing Center, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788; Department of Mechanical Engineering, School of Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788.
    Ejeh, Chukwugozie J.
    Advanced Digital & Additive Manufacturing Center, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788; Department of Mechanical Engineering, School of Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788.
    Barsoum, Imad
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Advanced Digital & Additive Manufacturing Center, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates; Department of Mechanical Engineering, School of Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates.
    Abu Al-Rub, Rashid K.
    Advanced Digital & Additive Manufacturing Center, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788; Department of Mechanical Engineering, School of Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, P.O. Box 127788.
    Review of Additively Manufactured Polymeric Metamaterials: Design, Fabrication, Testing and Modeling2023In: Polymers, E-ISSN 2073-4360, Vol. 15, no 19, article id 3858Article, review/survey (Refereed)
    Abstract [en]

    Metamaterials are architected cellular materials, also known as lattice materials, that are inspired by nature or human engineering intuition, and provide multifunctional attributes that cannot be achieved by conventional polymeric materials and composites. There has been an increasing interest in the design, fabrication, and testing of polymeric metamaterials due to the recent advances in digital design methods, additive manufacturing techniques, and machine learning algorithms. To this end, the present review assembles a collection of recent research on the design, fabrication and testing of polymeric metamaterials, and it can act as a reference for future engineering applications as it categorizes the mechanical properties of existing polymeric metamaterials from literature. The research within this study reveals there is a need to develop more expedient and straightforward methods for designing metamaterials, similar to the implicitly created TPMS lattices. Additionally, more research on polymeric metamaterials under more complex loading scenarios is required to better understand their behavior. Using the right machine learning algorithms in the additive manufacturing process of metamaterials can alleviate many of the current difficulties, enabling more precise and effective production with product quality.

  • 9.
    Al-Zubaidy, M. N.
    et al.
    University of Newcastle .
    Chan, J. F. L.
    University of Newcastle .
    Gibson, A. G.
    University of Newcastle .
    Toll, Staffan
    Chalmers.
    Properties of orthotropic glass-polypropylene composites manufactured by weaving of prepreg tapes and other routes2000In: Plastics, Rubber and Composites Processing and Applications, ISSN 0959-8111, Vol. 29, no 10, p. 520-526Article in journal (Refereed)
    Abstract [en]

    This paper reports a study of the melt impregnation and weaving of glass-polypropylene prepreg tapes into sheet for use as a precursor for pressed thermoplastic composite products and a comparison of the properties attainable with those achievable by other comparable routes. Melt impregnation has been used successfully to manufacture well impregnated tapes, with and without internal coupling agent. It appears that weaving could be an economically viable process for converting unidirectional tape into a conformable, press formable prepreg. The properties of glass-polypropylene laminates manufactured by pressing the tape woven product were compared with those of other glass-polypropylene composites, including crossply laminate made from Plytron and samples prepared by film stacking. Quasi-static mechanical properties were found to be comparable with those of Plytron and superior to those of the other materials. In the coupled samples, coupling was somewhat less effective than in Plytron. The impact behaviour of the pressed, tape woven products was impressive and superior to any of the other materials tested. © 2000 IoM Communications Ltd.

  • 10.
    Alzweighi, Mossab
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Modelling Fiber Network Materials:Micromechanics, Constitutive Behaviour and AI2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on understanding the mechanical behavior of fiber-based materials by utilizing various modeling approaches. Particular emphasis is placed on their structural variability, anisotropic properties, and damage behavior. Furthermore, the study explores moisture diffusion phenomena within these materials, leveraging machine learning techniques. The research employs a blend of multiscale modeling, experimental investigation, machine learning, and continuum modeling to enhance the predictive capabilities for modelling fiber-based materials.

    In Paper I, the work investigates the impact of stochastic variations in the structural properties of thin fiber networks on their mechanical performance. A multiscale approach that includes modeling, numerical simulation, and experimental measurements is proposed to assess this relationship. The research also considers the influence of drying conditions during production on fiber properties. The study finds that spatial variability in density has a significant impact on local strain fields, while fiber orientation angle with respect to drying restraints is a key influencer of the mechanical response. In Paper II, the research delves into the investigation of anisotropic properties and pressure sensitivity of fiber network materials. It draws a comparison between the Hoffman yield criterion and the Xia model, which are widely utilized for simulating the mechanical response in fiber-based materials. The study performs a detailed analysis of these models under bi-axial loading conditions, assessing their numerical stability and calibration flexibility. Further supporting the research community, the paper provides open-source access to the user material implementations of both models and introduces a calibration tool specifically for the Xia model, thereby promoting ease of usage and facilitating further research in this domain. In Paper III a novel thermodynamically consistent continuum damage model for fiber-based materials is introduced. Through the integration of elastoplasticity and damage mechanisms, the model employs non-quadratic surfaces comprised of multi sub-surfaces, augmented with an enhanced gradient damage approach. The model’s capability is demonstrated by predicting the nonlinear mechanical behavior under in-plane loading. This study provides valuable insights into the damage behavior of fiber-based materials, showcasing a range of failure modes from brittle-like to ductile. In Paper IV, the study examines moisture penetration in fiber-based materials and the resultant out-of-plane deformation, known as curl deformation, using a combination of traditional experiments, machine learning techniques, and continuum modeling. The paper compares the effectiveness of two machine learning models, a Feedforward Neural Network (FNN) and a Recurrent Neural Network (RNN), in predicting the gradient of the moisture profile history. The study finds that the RNN model, which accounts for temporal dependencies, provides superior accuracy. The predicted gradient moisture profile enables simulating the curl response, offering a deeper understanding of the relationship between moisture penetration and paper curling.

    Download full text (pdf)
    Kappa
  • 11.
    Alzweighi, Mossab
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Mansour, Rami
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Tryding, Johan
    Kulachenko, Artem
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Evaluation of Hoffman and Xia plasticity models against bi-axial tension experiments of planar fiber network materials2022In: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 238, article id 111358Article in journal (Refereed)
    Abstract [en]

    The anisotropic properties and pressure sensitivity are intrinsic features of the constitutive response of fiber network materials. Although advanced models have been developed to simulate the complex response of fibrous materials, the lack of comparative studies may lead to a dubiety regarding the selection of a suitable method. In this study, the pressure-sensitive Hoffman yield criterion and the Xia model are implemented for the plane stress case to simulate the mechanical response under a bi-axial loading state. The performance of both models is experimentally assessed by comparison to bi-axial tests on cruciform-shaped specimens loaded in different directions with respect to the material principal directions. The comparison with the experimentally measured forces shows the ability of the Hoffman model as well as the Xia model with shape parameter k≤2 to adequately predict the material response. However, this study demonstrates that the Xia model consistently presents a stiffer bi-axial response when k≥3 compared to the Hoffman model. This result highlights the importance of calibrating the shape parameter k for the Xia model using a bi-axial test, which can be a cumbersome task. Also, for the same tension-compression response, the Hill criterion as a special case of the Hoffman model presents a good ability to simulate the mechanical response of the material for bi-axial conditions. Furthermore, in terms of stability criteria, the Xia model is unconditionally convex while the convexity of the Hoffman model is a function of the orthotropic plastic matrix. This study not only assesses the prediction capabilities of the two models, but also gives an insight into the selection of an appropriate constitutive model for material characterization and simulation of fibrous materials. The UMAT implementations of both models which are not available in commercial software and the calibration tool of the Xia model are shared with open-source along with this work. 

    Download full text (pdf)
    fulltext
  • 12.
    Alzweighi, Mossab
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Tryding, Johan
    Division of Solid Mechanics, Lund University, Ole Römers väg 1, 223 63 Lund, Sweden;Tetra Pak, Ruben Rausings gata, 221 86 Lund, Sweden.
    Mansour, Rami
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics. Department of Mechanical and Production Engineering, Aarhus University, 8200 Aarhus N, Denmark.
    Borgqvist, Eric
    Tetra Pak, Ruben Rausings gata, 221 86 Lund, Sweden.
    Kulachenko, Artem
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Anisotropic damage behavior in fiber-based materials: Modeling and experimental validation2023In: Journal of the mechanics and physics of solids, ISSN 0022-5096, E-ISSN 1873-4782, Vol. 181, article id 105430Article in journal (Refereed)
    Abstract [en]

    This study presents a thermodynamically consistent continuum damage model for fiber-based materials that combines elastoplasticity and damage mechanisms to simulate the nonlinear mechanical behavior under in-plane loading. The anisotropic plastic response is characterized by a non-quadratic yield surface composed of six sub-surfaces, providing flexibility in defining plastic properties and accuracy in reproducing material response. The damage response is modeled based on detailed uniaxial monotonic and cyclic tension-loaded experiments conducted on specimens extracted from a paper sheet in various directions. To account for anisotropic damage, we propose a criterion consisting of three sub-surfaces representing tension damage in the in-plane material principal directions and shear direction, where the damage onset is determined through cyclic loading tests. The damage evolution employs a normalized fracture energy concept based on experimental observation, which accommodates an arbitrary uniaxial loading direction. To obtain a mesh-independent numerical solution, the model is regularized using the implicit gradient enhancement by utilizing the linear heat equation solver available in commercial finite-element software. The study provides insights into the damage behavior of fiber-based materials, which can exhibit a range of failure modes from brittle-like to ductile, and establishes relationships between different length measurements.

  • 13. Andre, A.
    et al.
    Norrby, Monica
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Åkermo, Malin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Nilsson, S.
    Nyman, Teresia
    KTH.
    An experimental and numerical study of the effect of some manufacturing defects2013In: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2013, p. 4105-4112Conference paper (Refereed)
    Abstract [en]

    During the manufacturing process of composite structural parts, layer of fabrics or unidirectional prepreg may have to be cut in order to fulfil production requirements. From a general mechanical point of view, cutting fibres in a composite part has a large negative impact on the mechanical properties. However, such interventions are necessary in particular cases, for example due to draping of complex geometries. A rather extensive test program was launched to investigate the effects of defects that typically could arise during manufacturing. The overall purpose of the test program was to determine knock-down factors on strength for typical manufacturing defects that occasionally arise and sometimes are hard to avoid in production: cuts/gaps and fibre angle deviations. Four types of specimens were tested, reference, intersection of cuts in adjacent layers combined with a bolt hole, cut in a zero degree ply combined with a bolt hole and specimens with misaligned fibres. The specimens with misaligned fibres were tested with three different fibre angles. In addition to the experimental procedure, FE-analyses utilising cohesive elements were conducted, and after mechanical tests, Non Destructive Investigation (NDI) and fractographic investigations were performed. An excellent correlation between analyses and experiments were obtained. 

  • 14.
    Anfossi, Maeva
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Hjortzberg-Nordlund, Emma
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Lundemo Mattsson, Linnéa
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Analysis of granulated carbide powder and how it affects pressing2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    During the pressing of powder mixtures to make cemented carbide tools, the degree to which the powder spreads to fill the die and to which it compacts is uncertain. This leads to inconsistent dimensions and densities in the finished product. This performance changes with the composition of the powder, including the amount of pressing agent in the mixture, the particle size distribution and particle shape.

    One way to quantify the degree to which powder will spread to fill the mold evenly is using the property called 'flowability'. There are several techniques by which flowability can be measured, and each technique does not always give results that are consistent with other techniques. It is, therefore, important to know what technique(s) predict(s) the final behavior of the powder in this application before it is used in quality assurance or to design a process. Additionally, powder size distribution and shape metrics are measured using dynamic image analysis to investigate if there is any relationship between key values of these properties and compaction behavior.

    In this study, static Angle of repose, Tap Density, Hall flow time and Powder rheometry were benchmarked against each other and against the dimensions of presses and liquid phase sintered tool inserts to understand which technique had the strongest dependence on the compactability, which was defined as the ratio of the tallest dimension in the insert to the smallest.

    After the study, the results showed that a more extensive particle size distribution improves the compaction properties and that the powders with a higher resistance to a rotating blade tend to have better compaction properties. On the other hand, a clear pattern for the results of all measurement methods and the correlation between the compaction behavior of the carbide tools could not be discerned. In conclusion, the study showed that it is possible to determine a relationship between the results of measurement methods and the compaction behavior of powders.

    By using simple tests to predict the compactability properties, both money and time can be saved on the research of new, improved powder. Furthermore, the implementation of this study can lead to even better pressing and compactibility properties in the future for cemented carbide tools.

    Download full text (pdf)
    fulltext
  • 15.
    Ansari, Farhan
    et al.
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Ding, Yichuan
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Dauskardt, Reinhold H.
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Toward Sustainable Multifunctional Coatings Containing Nanocellulose in a Hybrid Glass Matrix2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 6, p. 5495-5503Article in journal (Refereed)
    Abstract [en]

    We report on a sustainable route to protective nanocomposite coatings, where one of the components, nanocellulose fibrils, is derived from trees and the glass matrix is an inexpensive sol-gel organic-inorganic hybrid of zirconium alkoxide and an epoxy-functionalized silane. The hydrophilic nature of the colloidal nanocellulose fibrils is exploited to obtain a homogeneous one-pot suspension of the nanocellulose in the aqueous sol-gel matrix precursors solution. The mixture is then sprayed to form nano composite coatings of a well-dispersed, random in-plane nano cellulose fibril network in a continuous organic inorganic glass matrix phase. The nanocellulose incorporation in the sol-gel matrix resulted in nanostructured composites with marked effects on salient coating properties including optical transmittance, hardness, fracture energy, and water contact angle. The particular role of the nanocellulose fibrils on coating fracture properties, important for coating reliability, was analyzed and discussed in terms of fibril morphology, molecular matrix, and nanocellulose/matrix interactions.

  • 16.
    Ansari, Farhan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Salajkova, Michaela
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Zhou, Qi
    KTH, School of Biotechnology (BIO). KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Cellulose nanocomposites - Controlling dispersion and material properties through nanocellulose surface modification2015In: 20th International Conference on Composite Materials, ICCM 2015, International Committee on Composite Materials , 2015Conference paper (Refereed)
    Abstract [en]

    The use of cellulosic nanofibers as reinforcement in polymer composites offers great advantages over their petroleum counterparts. Apart from being strong, stiff and low density; they are obtained from naturally occurring resources and as such are favorable from an environmental point of view. A major problem while studying nanomaterials is their tendency to agglomerate, thus leading to inhomogeneous distribution within the polymer matrix. This often results in stress concentrations in the matrix rich regions when the material is subjected to load and therefore, limits the potential application of these materials. A common approach to circumvent this is by surface modification, which facilitates the dispersion in non-polar matrices. An environmental friendly approach, inspired by clay chemistry, was used to functionalize the CNC surface. It was shown that the CNC could be modified in a rather convenient way to attach a variety of functional groups on the surface. Primarily, the problem of cellulose nanocrystal (CNC) distribution in a hydrophobic polymer matrix is investigated. Composites prepared from modified CNC were studied and compared with unmodified CNC. The distribution of the CNC is carefully monitored at different stages via UV-Vis spectroscopy and scanning electron microscopy (SEM). The mechanical properties of the resulting materials were characterized by dynamic mechanical as well as uniaxial tensile tests. It was shown that a homogeneous distribution of the CNC exposes a tremendous amount of surface area to interact with the matrix. In such a case, the stress transfer is much more efficient and perhaps, the matrix behavior is modified, which leads to significant improvements in the mechanical properties.

  • 17.
    Arcieri, Nicolò
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Politecnico di Torino, Department of Applied Science and Technology, C.so Duca degli Abruzzi 24, 10129 Turin, Italy.
    Chen, Bin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Tavares da Costa, Marcus Vinicius
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Karlstad University, Department of Engineering and Chemical Sciences, SE-651 88 Karlstad, Sweden.
    Crack growth study of wood and transparent wood-polymer composite laminates by in-situ testing in weak TR-direction2023In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 173, article id 107693Article in journal (Refereed)
    Abstract [en]

    TW transparent wood/polymer biocomposite laminates are of interest as multifunctional materials with good longitudinal modulus, tensile strength and optical transmittance. The effect of filling the pore space in wood with a polymer matrix on fracture toughness and crack growth is not well understood. Here, we carried out in-situ fracture tests on neat birch wood and laminates made of four layers of delignified birch veneers impregnated with poly(methyl methacrylate) (PMMA) and investigated crack growth in the tangential-radial (TR) fracture system. Fracture toughness KIc and JIc at crack initiation were estimated, including FEM analysis. SEM microscopy revealed that cracks primarily propagate along the ray cells, but cell wall peeling and separation between the PMMA and wood phases also take place. A combination of in-situ tests and strain field measured by digital image correlation (DIC) showed twice as long fracture process zone of TW laminates compared with neat birch.

  • 18.
    Asp, Leif E.
    et al.
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Bouton, Karl
    Carlstedt, David
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Duan, Shanghong
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Harnden, Ross
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Johannisson, Wilhelm
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Johansen, Marcus
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Liu, Fang
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Peuvot, Kevin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Schneider, Lynn Maria
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Xu, Johanna
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    A Structural Battery and its Multifunctional Performance2021In: Advanced Energy and Sustainability Research, E-ISSN 2699-9412, Vol. 2, no 3, article id 2000093Article in journal (Refereed)
    Abstract [en]

    Engineering materials that can store electrical energy in structural load paths can revolutionize lightweight design across transport modes. Stiff and strong batteries that use solid-state electrolytes and resilient electrodes and separators are generally lacking. Herein, a structural battery composite with unprecedented multifunctional performance is demonstrated, featuring an energy density of 24 Wh kg−1 and an elastic modulus of 25 GPa and tensile strength exceeding 300 MPa. The structural battery is made from multifunctional constituents, where reinforcing carbon fibers (CFs) act as electrode and current collector. A structural electrolyte is used for load transfer and ion transport and a glass fiber fabric separates the CF electrode from an aluminum foil-supported lithium–iron–phosphate positive electrode. Equipped with these materials, lighter electrical cars, aircraft, and consumer goods can be pursued.

  • 19. Asp, Leif E
    et al.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Xu, Johanna
    Chalmers tekniska högskola.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Carbon Fibre Composite Structural Batteries: A Review2019In: Functional Composites and Structures, ISSN 2631-6331, article id 042001Article in journal (Refereed)
    Abstract [en]

    This paper presents a comprehensive review of the state-of-the-art in structural battery composites research. Structural battery composites are a class of structural power composites aimed to provide mass-less energy storage for electrically powered structural systems. Structural battery composites are made from carbon fibres in a structural electrolyte matrix material. Neat carbon fibres are used as a structural negative electrode, exploiting their high mechanical properties, excellent lithium insertion capacity and high electrical conductivity. Lithium iron phosphate coated carbon fibres are used as the structural positive electrode. Here, the lithium iron phosphate is the electrochemically active substance and the fibres carry mechanical loads and conduct electrons. The surrounding structural electrolyte is lithium ion conductive and transfers mechanical loads between fibres. With these constituents, structural battery half-cells and full-cells are realised with a variety in device architecture. The paper also presents an overview of material modelling and characterisation performed to date. Particular reference is given to work performed in national and European research projects under the leadership of the authors, who are able to provide a unique insight into this emerging and exciting field of research.

    Download full text (pdf)
    fulltext
  • 20.
    Asp, Leif E.
    et al.
    Swerea SICOMP AB, Box 104, SE-43122 Mölndal, Sweden.;Chalmers Univ Technol, Dept Appl Mech, SE-41296 Gothenburg, Sweden..
    Leijonmarck, Simon
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH). Swerea SICOMP AB, Box 104, SE-43122 Mölndal, Sweden..
    Carlson, Tony
    Swerea SICOMP AB, Box 104, SE-43122 Mölndal, Sweden..
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Realisation Of Structural Battery Composite Materials2015In: 20Th International Conference On Composite Materials / [ed] Thomsen, OT Berggreen, C Sorensen, BF, AALBORG UNIV PRESS , 2015Conference paper (Refereed)
    Abstract [en]

    This paper introduces the concept of structural battery composite materials and their possible devices and the rationale for developing them. The paper presents an overview of the research performed in Sweden on a novel structural battery composite material. The research areas addressed include: carbon fibre electrodes, structural separators, multifunctional matrix materials, device architectures and material functionalization. Material characterization, fabrication and validation are also discussed. The paper focuses on a patented battery composite material technology. Here, carbon fibres are employed as combined negative battery electrodes and reinforcement, coated with a solid polymer electrolyte working simultaneously as electrolyte and separator with ability to transfer mechanical loads. The coated fibres are distributed in a conductive positive cathode material on an aluminium electron collector film. Efficient Li-ion transport between the electrodes is achieved by the solid polymer electrolyte coating being only a few hundred nanometres thick. Finally some outstanding scientific and engineering challenges are discussed. Such challenges, calling for further research are related to manufacture, development of new solid polymer electrolytes for improved multifunctionality and the lack of material models.

  • 21. Badia, J. D.
    et al.
    Reig-Rodrigo, P.
    Teruel-Juanes, R.
    Kittikorn, Thorsak
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Prince of Songkla University, Thailand.
    Strömberg, Emma
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ribes-Greus, A.
    Effect of sisal and hydrothermal ageing on the dielectric behaviour of polylactide/sisal biocomposites2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 149, p. 1-10Article in journal (Refereed)
    Abstract [en]

    The dielectric properties of virgin polylactide (PLA) and its reinforced composites with different weight amounts of sisal fibres were assessed at broad temperature (from −130 °C to 130 °C) and frequency ranges (from 10−2–107 Hz), before and after being subjected to accelerated hydrothermal ageing. The synergetic effects of both the loading of sisal and hydrothermal ageing were analysed by means of dielectric relaxation spectra. The relaxation time functions were evaluated by the Havriliak-Negami model, substracting the ohmic contribution of conductivity. The intramolecular and intermolecular relaxations were respectively analysed by means of Arrhenius and Vogel-Fulcher-Tammann-Hesse thermal activation models. The addition of fibre increased the number of hydrogen bonds, which incremented the dielectric permittivity and mainly hindered the non-cooperative relaxations of the biocomposites by increasing the activation energy. Hydrothermal ageing enhanced the formation of the crystalline phase at the so-called transcrystalline region along sisal. This fact hindered the movement of the amorphous PLA fraction, and consequently decreased the dielectric permittivity and increased the dynamic fragility.

  • 22.
    Bengtsson, Andreas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. RISE Research Institutes of Sweden AB.
    Biobased carbon fibers from solution spun lignocellulosic precursors2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Carbon fibers (CFs) have excellent mechanical properties and a low density, making themattractive as a reinforcing fiber in composites. The use of CFs is limited to high-end applications,since they are produced from an expensive fossil-based precursor via an energy-intensivemanufacturing process, explaining the need for cheaper CFs from renewables. CFs can be madefrom strong cellulosic precursors, but the low carbon content of cellulose results in a lowconversion yield, and thus an expensive CF. Lignin has a higher carbon content than cellulose butCFs from melt spun lignin precursors have presented challenges, since these precursors have a lowstrength and are difficult to convert to CF in a realistic conversion time.In the present work, CFs from solution spun precursors consisting of blends of softwood kraftlignin and cellulose have been developed. The lignin-cellulose precursors (up to 70% lignin) wereprepared with air-gap spinning and wet spinning, using an ionic liquid and a water-based solventsystem for co-dissolution, respectively. Co-processing of cellulose and lignin was beneficial as theformer made the precursor strong and easy to handle, whereas the latter gave a higher conversionyield than precursors based solely on cellulose. The precursors were converted to CFs via bothbatchwise and continuous conversion, using industrially relevant times (< 2 h), with a yield up to45 wt% after incorporation of a flame retardant.These CFs have a moderate Young’s modulus and tensile strength up to 75–77 GPa and 1.2 GPa,respectively, i.e. similar to the values for CFs from fossil-based isotropic pitch and they can thusbe classified as general-grade CFs. These biobased CFs have a disordered turbostratic graphitestructure, and their tensile properties are affected by the precursor structure, the conversionconditions, and the final diameter. These CFs can potentially be used as a sustainable componentin non-structural and semi-structural applications.

    Download full text (pdf)
    Thesis
  • 23.
    Bengtsson, Andreas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology.
    Carbon fibres from lignin-cellulose precursors2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    It is in the nature of the human species to find solutions of complex technical problems and always strive for improvements. The development of new materials is not an exception. One of the many man-made materials is carbon fibre (CF). Its excellent mechanical properties and low density have made it attractive as the reinforcing agent in lightweight composites. However, the high price of CF originating from expensive production is currently limiting CF from wider utilisation, e.g. in the automotive sector.

     

    The dominating raw material used in CF production is petroleum-based polyacrylonitrile (PAN). The usage of fossil-based precursors and the high price of CF explain the strong driving force of finding cheaper and renewable alternatives. Lignin and cellulose are renewable macromolecules available in high quantities. The high carbon content of lignin is an excellent property, while its structural heterogeneity yields in CF with poor mechanical properties. In contrast, cellulose has a beneficial molecular orientation, while its low carbon content gives a low processing yield and thus elevates processing costs.

     

    This work shows that several challenges associated with CF processing of each macromolecule can be mastered by co-processing. Dry-jet wet spun precursor fibres (PFs) made of blends of softwood kraft lignin and kraft pulps were converted into CF. The corresponding CFs demonstrated significant improvement in processing yield with negligible loss in mechanical properties relative to cellulose-derived CFs. Unfractionated softwood kraft lignin and paper grade kraft pulp performed as good as more expensive retentate lignins and dissolving grade kraft pulp, which is beneficial from an economic point of view.

     

    The stabilisation stage is considered the most time-consuming step in CF manufacturing. Here it was shown that the PFs could be oxidatively stabilised in less than 2 h or instantly carbonised without any fibre fusion, suggesting a time-efficient processing route. It was demonstrated that PF impregnation with ammonium dihydrogen phosphate significantly improves the yield but at the expense of mechanical properties.

     

    A reduction in fibre diameter was beneficial for the mechanical properties of the CFs made from unfractionated softwood kraft lignin and paper grade kraft pulp. Short oxidative stabilisation (<2 h) of thin PFs ultimately provided CFs with tensile modulus and strength of 76 GPa and 1070 MPa, respectively. Considering the high yield (39 wt%), short stabilisation time and promising mechanical properties, the concept of preparing CF from lignin:cellulose blends is a very promising route.

    Download full text (pdf)
    Carbon fibres from lignin-cellulose precursors
  • 24.
    Bengtsson, Andreas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. Division Bioeconomy and Health, RISE Research Institutes of Sweden, P.O. Box 5604, SE-114 86 Stockholm, Sweden.
    Carbon fibres from wet spun cellulose-ligninprecursors using the cold alkali processManuscript (preprint) (Other academic)
    Download full text (pdf)
    fulltext
  • 25.
    Bengtsson, Andreas
    et al.
    Division Bioeconomy and Health, RISE Research Institutes of Sweden, P.O. Box 5604, SE-114 86 Stockholm, Sweden.
    Bengtsson, Jenny
    Division Material and Production, RISE Research Institutes of Sweden, P.O. Box 104, SE-431 22 Mölndal, Sweden.
    Jedvert, Kerstin
    Division Material and Production, RISE Research Institutes of Sweden, P.O. Box 104, SE-431 22 Mölndal, Sweden.
    Kakkonen, Markus
    Fibrobotics OY, Korkeakoulunkatu 1, FI-33720 Tampere, Finland.
    Tanhuanpää, Olli
    Fibrobotics OY, Korkeakoulunkatu 1, FI-33720 Tampere, Finland.
    Brännvall, Elisabet
    Division Bioeconomy and Health, RISE Research Institutes of Sweden, P.O. Box 5604, SE-114 86 Stockholm, Sweden.
    Sedin, Maria
    Division Bioeconomy and Health, RISE Research Institutes of Sweden, P.O. Box 5604, SE-114 86 Stockholm, Sweden.
    Continuous Stabilization and Carbonization of a Lignin–Cellulose Precursor to Carbon Fiber2022In: ACS Omega, E-ISSN 2470-1343, Vol. 7, no 19, p. 16793-16802Article in journal (Refereed)
    Abstract [en]

    : The demand for carbon fibers (CFs) based onrenewable raw materials as the reinforcing fiber in composites forlightweight applications is growing. Lignin−cellulose precursorfibers (PFs) are a promising alternative, but so far, there is limitedknowledge of how to continuously convert these PFs underindustrial-like conditions into CFs. Continuous conversion is vitalfor the industrial production of CFs. In this work, we havecompared the continuous conversion of lignin−cellulose PFs (50wt % softwood kraft lignin and 50 wt % dissolving-grade kraft pulp)with batchwise conversion. The PFs were successfully stabilizedand carbonized continuously over a total time of 1.0−1.5 h,comparable to the industrial production of CFs from polyacrylonitrile. CFs derived continuously at 1000 °C with a relative stretch of−10% (fiber contraction) had a conversion yield of 29 wt %, a diameter of 12−15 μm, a Young’s modulus of 46−51 GPa, and atensile strength of 710−920 MPa. In comparison, CFs obtained at 1000 °C via batchwise conversion (12−15 μm diameter) with arelative stretch of 0% and a conversion time of 7 h (due to the low heating and cooling rates) had a higher conversion yield of 34 wt%, a higher Young’s modulus (63−67 GPa) but a similar tensile strength (800−920 MPa). This suggests that the Young’s moduluscan be improved by the optimization of the fiber tension, residence time, and temperature profile during continuous conversion,while a higher tensile strength can be achieved by reducing the fiber diameter as it minimizes the risk of critical defects.

    Download full text (pdf)
    fulltext
  • 26.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wood biocomposites and structural fibre materials2021In: Mechanics of Paper Products, Walter de Gruyter GmbH , 2021, p. 281-309Chapter in book (Other academic)
  • 27.
    Berglund, Lars A.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Peijs, Ton
    Cellulose Biocomposites: From Bulk Moldings to Nanostructured Systems2010In: MRS bulletin, ISSN 0883-7694, E-ISSN 1938-1425, Vol. 35, no 3, p. 201-207Article in journal (Refereed)
    Abstract [en]

    Cellulose biocomposites are widely used in industry as a low-cost engineering material with plant fiber reinforcement. However, chemical and microstructural heterogeneity causes low strength, low strain-to-failure, high moisture sensitivity, and odor and discoloration problems. Efforts toward improved performance through fiber orientation control, increased fiber lengths, and biopolymer use are reviewed. Interfacial strength control and moisture sensitivity are remaining challenges. As an attractive alternative reinforcement, high-quality cellulose nanofibers obtained by wood pulp fiber disintegration can be prepared at low cost. These nanofibers have high length/diameter ratios, diameters in the 5-15 nm range, and intrinsically superior physical properties. Wood cellulose nanofibers are interesting as an alternative reinforcement to more expensive nanoparticles, such as carbon nanotubes. Nanopaper and polymer matrix nanocomposites based on cellulose nanofiber networks show high strength, high work-of-fracture, low moisture adsorption, low thermal expansion, high thermal stability, high thermal conductivity, exceptional barrier properties, and high optical transparency. The favorable mechanical performance of bioinspired foams and low-density aerogels is reviewed. Future applications of cellulose biocomposites will be extended from the high-volume/low-cost end toward high-tech applications, where cellulose properties are fully exploited in nanostructured materials.

  • 28.
    Berglund, Lars
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ansari, Farhan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Cellulose Nanocomposites With Ductile Mechanical Behavior2015In: 20Th International Conference On Composite Materials / [ed] Thomsen, OT Berggreen, C Sorensen, BF, AALBORG UNIV PRESS , 2015Conference paper (Refereed)
    Abstract [en]

    The limited ductility of plant fiber biocomposites is typically caused by interfacial debonding mechanisms at low strain. This leads to damage development and premature failure. The present paper discusses recent results on cellulose nanocomposites with thermoset and thermoplastic matrices, where substantial ductility is observed. The data are presented and reasons for the observed ductility are discussed.

  • 29.
    Berglund, Lars
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Burgert, Ingo
    Swiss Fed Inst Technol, Inst Bldg Mat, Stefano Franscini Pl 3, CH-8093 Zurich, Switzerland.;EMPA Swiss Fed Labs Mat Testing & Res, Appl Wood Res Lab, CH-8600 Dubendorf, Switzerland..
    Bioinspired Wood Nanotechnology for Functional Materials2018In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 30, no 19, article id 1704285Article in journal (Refereed)
    Abstract [en]

    It is a challenging task to realize the vision of hierarchically structured nanomaterials for large-scale applications. Herein, the biomaterial wood as a large-scale biotemplate for functionalization at multiple scales is discussed, to provide an increased property range to this renewable and CO2-storing bioresource, which is available at low cost and in large quantities. The Progress Report reviews the emerging field of functional wood materials in view of the specific features of the structural template and novel nanotechnological approaches for the development of wood-polymer composites and wood-mineral hybrids for advanced property profiles and new functions.

  • 30.
    Berglund, Lina
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The Effect of Cooling Rate on Sintered Cemented Carbides2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Magnetic measurements are useful tools for quality control of cemented carbides. Previous work at Sandvik Mining and Rock Technology has shown that the coercivity increases with increased cooling rate during sintering for a specific grade.  This study aims to investigate why the coercivity changes with the cooling rate and if this is true for other cemented carbide grades as well. Three different cemented carbide grades were sintered with different cooling rates and evaluated with coercivity, Cobalt-magnetic saturation and hardness measurements, and with microscopy and Electron Backscatter Diffraction analysis.

    It was found that the coercivity increased with increasing cooling rates for the previously studied grade, but not for the two other grades. It was expected that the increased coercivity would indicate a decrease in WC grain size, but the results showed that the WC grain size of the fastest and slowest cooling rate were the same. However, a change in size of the Co areas between the WC grains was found. The fast cooled sample showed smaller Co areas than the slow cooled sample. These Co/WC grain boundaries increase the coercivity. An increased fraction of hcp-Co/fcc-Co was also found for the fast cooled material which also increases the coercivity.

    No relationship between the hardness and the coercivity or the cooling rate was found.   The contiguity for the different grades was also calculated.  No significant difference in contiguity between the different cooling rates of each material was found but the contiguity values between the different materials differed.  This is probably mainly dependent on the different binder contents of the materials.

    Download full text (pdf)
    fulltext
  • 31.
    Besharat, Zahra
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Wakeham, Deborah
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Rutland, Mark W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Mixed monolayers of alkane thiols with polar terminal group on gold: Investigation of structure dependent surface properties2016In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 484, no 279, p. 279-290, article id j.jcis.2016.08.053Article in journal (Refereed)
    Abstract [en]

    Adsorption of thiols with cationic or anionic terminal group on gold has been studied from mixed solutions of 11-Amino-1-undecanethiol (AUT) and 3-Mercaptopropionic acid (MPA) using Quartz Crystal Microbalance with Dissipation (QCM-D), X-ray Photoelectron Spectroscopy (XPS), atomic force microscopy (AFM) and contact angles. The goal is to probe the nature of such layers, and the additivity or otherwise of the pH responsiveness, with a view to evaluate their suitability as smart materials. For each of the two pure (unmixed) cases, ordered molecular monolayers are formed with sulfur binding to gold and the alkane chain pointing out from the surface as expected. Adsorption from the thiol mixtures, however, leads to a more complex behaviour. The surface concentration of thiols from the mixtures, as determined by QCM-D, is considerably lower than for the pure cases and it reaches a minimum at a 3:1 MPA/AUT relative concentration in the solution. The XPS results confirm a reduction in adsorbed amount in mixtures with the lowest overall intensity for the 3:1 ratio. Monolayers formed from mixtures display a wettability which is much lower and less pH sensitive. Collectively these results confirm that for adsorption from mixed systems, the configuration is completely different. Complex formation in the mixed solutions leads to the adsorption of molecules parallel to the surface in an axially in-plane configuration. This parallel layer of thiols is mechanically relatively robust to nano-shaving based on AFM measurements. These results will have a significant impact on the design of biomimetic surface coatings particularly when mixtures of oppositely charged molecules are present on the surface, as is commonly the case in biological, proteinaceous surfaces (e.g. hair and skin).

  • 32.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. UM-DAE Centre for Excellence in Basic Sciences, Mumbai, India.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Consistent description of the cluster-decay phenomenon in transactinide nuclei2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 4Article in journal (Refereed)
    Abstract [en]

    Systematic investigation of the known even-even transactinide cluster emitters has been carried out by considering the cluster as a point particle and using the exact quantum mechanical treatment of the decay process. It is shown that the cluster decay phenomenon can be described reasonably well using a simple Woods-Saxon mean field. Sensitivity of the half-lives on various aspects of the mean field has been investigated in detail.

  • 33.
    Boillat, Pauline
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Energy efficient fibre composites recycling2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this project, an investigation will be performed about how to improve thermal properties of recycled composite material. First, a literature study was performed about the potential techniques to improve the heating efficiency of the composites. Heating  techniques,  fibres  and  possible  fillers  were  investigated.    Secondely, an experimental method was set with the material available.   In the laboratory a precedent  work  was  performed  on  the  thermal  conductivity  of  polyamide  12 reinforced  with  glass  fibres.   The  conductivity  of  polyamide  12  reinforced with carbon fibres is measured using the same experimental method to compare the thermal conductivity. In theory, carbon fibres have a better thermal conductivity than glass fibres, this was confirmed by the experiments performed.  During the recycling of thermoplastic fibre composites the scrap will be grinded.  Therefore, the thermal conductivity of small pieces of carbon fibre composites was measured, the  thermal  conductivity  is  reduced  due  to  the  increase  of  air  fraction  and the shortening of the fibres.  The thermal conductivity of small pieces of glass fibre composite was investigated in the previous work, by mixing the grinded pieces of carbon fibre composite and the small pieces of the glass fibre composite the effect on the thermal conductivity was investigated.  It was noticed that using smaller pieces of grinded material allows to reduce the air fraction between the bigger pieces and increase the thermal conductivity.

    Download full text (pdf)
    fulltext
  • 34. Borst, Sem
    et al.
    Proutiere, Alexandre
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Shah, Devavrat
    Special Issue on Recent Trends in the Mathematics of Wireless Communication Networks: Algorithms, Models and Methods-Part 1 Introduction2012In: Queueing systems, ISSN 0257-0130, E-ISSN 1572-9443, Vol. 72, no 1-2, p. 1-3Article in journal (Other academic)
  • 35.
    Bouton, Karl
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lightweight Structures.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Chen, Brian
    The City College of New-York, Department of Chemical Engineering.
    Structural Positive Electrodes for Multifunctional Composite Materials.2019In: Proceedings of the 2019 International Conference on Composite Materials, 2019Conference paper (Other academic)
    Download full text (pdf)
    fulltext
  • 36.
    Brandberg, August
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Kulachenko, Artem
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    New insights into compressive strength of paper & board2019In: Paper Conference and Trade Show, PaperCon 2019, TAPPI Press , 2019, p. 1308-1313Conference paper (Refereed)
    Abstract [en]

    Compressive properties of fiber-based materials are linked to their performance as packaging materials. This is not only due to use under compressive loads such as stacking but also since compressive strength is lower than tensile strength, causing compressive properties to be the limit in all applications involving bending. We examine the effect of changing the network structure on short span compression strength using a numerical model. In this way, we overcome one of the major challenges of working on non-woven randomly oriented composited: performing controlled parametric studies. We show that the effect of changes made to fiber in- and out-of-plane orientation as well as non-uniform through-thickness density on compressive strength is small, but that stiffness and strain-tofailure may be altered using comparatively small structural modifications.

  • 37.
    Bryne, Lars Elof
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Lausamaa, J.
    Ernstsson, M.
    Englund, Finn
    Wålinder, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Söderström, Ove
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    UV-laser irradiated wood: Some aspects on micromorphology, wettability, surface composition and liquid permeability2008In: Proceedings of the 4th meeting of the Nordic-Baltic network in wood material science and engineering (WSE), 2008, p. 75-82Conference paper (Refereed)
    Abstract [en]

    Many wood products used as building or construction materials involve a combination of the wood material with polymers, such as adhesives, coatings, preservatives and binders in composites. Combinations of wood and polymers in outdoor exposure, however, in general have poor long-term durability. A major cause of the unsatisfactory durability can be related to the high hygroscopicity of wood and the great difference in hygro-thermal properties between the components, resulting in wood-polymer de-bonding. In addition, mechanical processing (e.g. sawing, sanding and planning) of wood in general forms a weak boundary layer of loose and crushed wood cells in the surface which also may interfere with the wood-polymer bonding. The main objective of this work was to study ultra violet (EV), or excimer, laser irradiation on wood as a means to remove, by ablation, the outer deformed layer from a wood substrate. Effects of the UV-laser treatment on wetting and liquid permeability characteristics were studied by Wilhelmy plate experiments, and effects on the wood surface chemistry were studied by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The micromorphology of wood was studied by low vacuum-scanning electron microscopy (LV-SEM). The pre-treatment of wood substrates by UV-laser ablation resulted in a notable changes in surface micromorphology, liquid permeability, wettability and surface chemistry characteristics.

  • 38. Budiman, B. A.
    et al.
    Juangsa, F. B.
    Aziz, M.
    Nurprasetio, I. P.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Experimental verification of interfacial strength effect on the mechanical properties of carbon fiber-epoxy composite2017In: International Journal on Advanced Science, Engineering and Information Technology, ISSN 2088-5334, E-ISSN 2460-6952, Vol. 7, no 6, p. 2226-2231Article in journal (Refereed)
    Abstract [en]

    The effects of carbon fiber-epoxy interfacial strength on the mechanical properties of the corresponding fiber-matrix composites are experimentally demonstrated in this work. Two composites containing different carbon fibers were tested: as-received fibers and fibers soaked in acetone to remove adhesive on their surfaces. The fiber surfaces were first characterized by scanning electron microscopy and time-of-flight secondary-ion mass spectrometry to verify removal of the adhesive. Further, single-fiber fragmentation tests were conducted to evaluate the fiber strength and the interfacial strength. The mechanical properties of the composites were evaluated via tensile testing under longitudinal and transverse loadings. The results show that interfacial strength does not decrease the mechanical properties of the composites under longitudinal loading. In contrast, under transverse loading, the interfacial strength significantly decreases the mechanical properties, specifically the ultimate tensile strength and toughness of the composites.

  • 39.
    Bull, Peter Hoaas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Curved sandwich beams with face-core debond subjected to bending moment2004In: Journal of Sandwich Structures and Materials, ISSN 1099-6362, E-ISSN 1530-7972, Vol. 6, no 2, p. 115-127Article in journal (Refereed)
    Abstract [en]

    Curved sandwich beams subjected to opening bending moment are studied. Face-core debonds of varying size are introduced at the compressively loaded face sheet and the structural integrity is investigated. Analytical and finite element models are compared in order to identify the governing failure modes of the beams. A simple expression is presented as a tool for getting a quick estimate of the severity of an interface crack in a curved sandwich beam. Five different configurations of beams are tested experimentally in a custom made bending rig.

  • 40.
    Bull, Peter Hoaas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    High-velocity and quasi-static impact of large sandwich panels2004In: Journal of Sandwich Structures and Materials, ISSN 1099-6362, E-ISSN 1530-7972, Vol. 6, no 2, p. 97-113Article in journal (Refereed)
    Abstract [en]

    An investigation of the response of sandwich structures subjected to impact velocities of virtually 0 m/s and approximately 1000 m/s is conducted. The higher velocity exceeds both the longitudinal and the transverse wave propagation velocities of the core material in the sandwich panels. The objective is to investigate the possibility to simulate the damage from ballistic impact of sandwich panels through quasi-static experiments. Panels are impacted using a 40 mm Bofors AA gun and, using a similar projectile, other panels are indented quasi-statically. Energy absorption is measured in both test series. After impact, the panels are tested in in-plane compression together with one undamaged panel for reference. Residual strength of impacted panels is analyzed by finite element analysis. It is shown that the damage from high-velocity impact is limited, and it is possible to regain most of the undamaged strength by repair.

  • 41.
    Burman, Magnus
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Composites in ships2010In: 1st conference on Service vessels for offshore wind park, 2010Conference paper (Other academic)
  • 42.
    Burman, Magnus
    KTH, Superseded Departments (pre-2005), Aeronautical and Vehicle Engineering.
    Residual Shear Strength of Polymeric Foams after Fatigue Testing2003In: 6:th International Conference on Sandwich Structures (ICSS-6), / [ed] Vinson, Rajapakse and Carlsson, New York: CRC Press , 2003, p. 522-529Conference paper (Other academic)
  • 43.
    Burman, Magnus
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Sandwich Materials in Buildings2005In: The 16th SICOMP Conference on Manufacturing and Design of Composites, 2005Conference paper (Other academic)
  • 44.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Colombo, C.
    Vergani, L.
    Static and fatigue characterisation of new basalt fibre reinforced composites2011In: 16th International Conference on Composite Structures, ICCS 16 / [ed] prof Antonio Ferreria, 2011Conference paper (Other academic)
  • 45.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Colombo, C.
    Vergani, L.
    Static and fatigue characterisation of new basalt fibre reinforced composites2012In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 94, no 3, p. 165-1174Article in journal (Refereed)
    Abstract [en]

    Basalt reinforced composites are recently developed materials. These mineral amorphousfibres are a valid alternative to carbon fibres for their lower cost, and to glass fibres for their strength.In order to use basalt reinforced composites for structural applications, it is necessary to perform amechanical characterization. With this aim in the present work experimental results of several staticand fatigue tests are described. Two polymeric matrices are taken into account, vinylester and epoxy,to assess their influence on the evaluated parameters. In parallel to these mechanical tests, also thethermal answer of the specimens to mechanical loads is evaluated by means of thermography. Thisexperimental technique allows defining the composite local heating during the application ofmechanical loads and its behaviour in details. Final discussion on obtained results is proposedfocussing the attention on basalt fibre composite behaviour, and comparing mechanical properties ofBFRP with other composite materials in glass and carbon fibres.

  • 46.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Fernades, A. A.
    Ferreria, A.
    Cirrone, G.
    Adams, R.
    Araujo, F.
    Scamuzzi, M.
    Ruiz, J.
    Fernandes, F.
    Vicente, T.
    Salomon, O.
    Ziegmann, G.
    Mauri, U.
    Vergani, L.
    LITEBUS - Modular Lightweight Sandwich Bus Concept2008In: Transport Research Arena - TRA 2008, 2008Conference paper (Other academic)
  • 47.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hedlund Åström, Anna
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Lingg, B.
    Villinger, S.
    Enlund, H.
    Hellbratt, S-E
    Cost and Energy Assessment of a High Speed Ship2008In: International Journal of Small Craft Technology, RINA - Part B, ISSN 1740-0694, Vol. 150, no 1, p. 1-10Article in journal (Refereed)
  • 48.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Kuttenkeuler, Jakob
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
    Comparative Life Cycle Assessment (LCA) of the Hull of a High Speed Craft2011In: 16th International Conference on Composite Structures / [ed] Prof Antonio Ferreria, 2011Conference paper (Other academic)
  • 49. Burman, Magnus
    et al.
    Lingg, B.
    Villinger, S.
    Enlund, H.
    Hedlund Åström, Anna
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Hellbratt, S-E
    Cost and energy assessment of a high speed ship2006In: Second Conference on High Performance Yacht Design, 2006Conference paper (Other academic)
    Abstract [en]

    A comparison in total life cycle costs and energy consumption for one high speed ship design with three different structural materials have been performed. The investigation considers a high speed ferry with a steel hull and an aluminium superstructure, an all aluminium concept and a ship built in sandwich material with carbon fibre faces. The different materials will affect several cost elements during the design, the production and the operation of the ship until and including its disposal. Furthermore, the material selection has an impact on the energy consumption within all stages of the ships life cycle. The assessment is made in a comparative manner. Hence, identical out fitting components, e.g. interior, instrumentation, and ventilation are left out. It is shown that the steel version causes the highest costs and energy consumption. The sandwich construction has the lowest life cycle costs while the aluminium version has the lowest energy consumption. The break-even point between the steel and the composite versions appears after 4 years (only 2 years of operation!), the break-even point between the aluminium and the composite ferry is after 12 years (10 years of operation). A sensitivity analysis with different possible scenarios, e.g. change in interest, petrol cost, maintenance cost, has been performed. All of the investigated scenarios identify the composite version to have the lowest life cycle costs. This paper summarises an original work carried out as a master of science work as given in [1-2].

  • 50.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Neves, P.
    Uni of Porto.
    Grimaldi, R.
    INSIA.
    Niemeyer, S.
    Univerity of Claustahl.
    Salomon, O.
    CIMNE.
    Ziegmann, G.
    Univerity of Claustahl.
    Ferreria, A.
    University of Porto.
    Fernandes, A.A.
    University of Porto.
    Bus Pillar Test Monitoring, Simulation and Validation2009In: 15th International Conference on Composite Structures, 2009Conference paper (Other academic)
1234567 1 - 50 of 437
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf