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Publications (10 of 93) Show all publications
Zhu, J., Khurshid, M. & Barsoum, Z. (2019). Accuracy of computational welding mechanics methods for estimation of angular distortion and residual stresses. Welding in the World, 63(5), 1391-1405
Open this publication in new window or tab >>Accuracy of computational welding mechanics methods for estimation of angular distortion and residual stresses
2019 (English)In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 63, no 5, p. 1391-1405Article in journal (Refereed) Published
Abstract [en]

This study estimates the angular distortion and residual stresses due to welding using the following methodologies: thermo-elastic-plastic, inherent strain (local-global), and substructuring on two types of welded joints (T-type fillet weld and butt weld). The numerical results are compared with the experimental measurements and these methodologies are evaluated in terms of accuracy and computational time. In addition, the influence of welding sequence on distortion and transverse residual stresses has been studied numerically by implementing the thermo-elastic-plastic and inherent strain (local-global) methods on the T-type fillet weld. For the T-type fillet weld, the estimated angular distortion from these methods is much the same and in good agreement with the experimental measurements. For the butt weld, the angular distortion calculated by the inherent strain (local-global) method is largely underestimated. In order to gain a better understanding of where the underestimation of angular distortion in the inherent strain (local-global) method comes from, the study discusses the influence of block length and welding speed on angular distortion. It is found that for long weld length or slow welding speed, activating the plastic strain gradually by dividing the weld bead into an appropriate number of blocks can reduce the level of underestimation of angular distortion.

Place, publisher, year, edition, pages
SPRINGER HEIDELBERG, 2019
Keywords
Angular distortion, Residual stresses, Thermo-elastic-plastic, Inherent strain, Substructuring
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-259424 (URN)10.1007/s40194-019-00746-9 (DOI)000482459300020 ()2-s2.0-85067672268 (Scopus ID)
Note

QC 20190924

Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-09-24Bibliographically approved
Stenberg, T., Barsoum, Z., Hedlund, J. & Josefsson, J. (2019). Development of a computational fatigue model for evaluation of weld quality. Welding in the World, 63(6), 1771-1785
Open this publication in new window or tab >>Development of a computational fatigue model for evaluation of weld quality
2019 (English)In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 63, no 6, p. 1771-1785Article in journal (Refereed) Published
Abstract [en]

The current study focuses on the development of a predictive model for assessing the fatigue life of welded joints based on measured weld geometry and applied load. Two different materials (S355 and S960) and two different material thicknesses (2 mm and 8 mm) were considered. Experiments on cruciform joints were conducted to evaluate the fatigue performance for different types of weld geometries. A computational model based on FEM and linear elastic fracture mechanics was developed and adapted to fit the experimental results using optimization and surrogate models. It is observed that the general fatigue behavior differs for the different materials for the same variation in geometry. The fatigue performance depends on a combination of geometrical parameters. The use of FAT curves according to the weld quality systems, e.g., ISO 5817, is insufficient to describe fatigue properties for welds in thin high strength steel, and different geometries within different weld quality levels can give the same fatigue behavior. It is also concluded that the developed computational model is suitable for further development of weld quality systems.

Place, publisher, year, edition, pages
Springer Verlag, 2019
Keywords
Computational model, Fatigue, Fracture mechanics, Weld quality, Welded joints, Computation theory, Computational methods, Geometry, High strength steel, Quality control, Welding, Welds, Different geometry, Fatigue performance, Fatigue properties, Linear elastic fracture mechanics, Material thickness, Predictive modeling, Fatigue of materials
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-263276 (URN)10.1007/s40194-019-00777-2 (DOI)2-s2.0-85069507812 (Scopus ID)
Note

QC 20191105

Available from: 2019-11-05 Created: 2019-11-05 Last updated: 2019-11-05Bibliographically approved
Baumgartner, J., Yıldırım, H. C. & Barsoum, Z. (2019). Fatigue strength assessment of TIG-dressed welded steel joints by local approaches. International Journal of Fatigue, 126, 72-78
Open this publication in new window or tab >>Fatigue strength assessment of TIG-dressed welded steel joints by local approaches
2019 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 126, p. 72-78Article in journal (Refereed) Published
Abstract [en]

Fatigue strength assessment methods by local approaches are widely used in the literature. This paper provides a comprehensive evaluation of published data for welded steel joints improved by TIG dressing methods. Fatigue classes for the local assessment methods with the available fatigue data are recommended. The available fatigue data extracted for transverse non-load carrying welds, cruciform joints as well as butt joints. In total, 17 published test series of weld details with various yield strengths and stress ratios are presented. Fatigue strength assessment is performed by considering the weld profile geometry within Finite Element models and taking the resulting stress gradients as basis for the evaluation. In addition, the influence of the steel grade is included. The most reliable results are derived by using the critical distance approach. Fatigue classes and critical distances are recommended as a result of the evaluations.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Fatigue design, Finite elements, Size effects, TIG-dressing, Welded joints, Finite element method, Microalloyed steel, Welding, Welds, Yield stress, Comprehensive evaluation, Cruciform joints, Fatigue strength assessment, Local approaches, Reliable results, TIG dressings, Fatigue of materials
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-252449 (URN)10.1016/j.ijfatigue.2019.04.038 (DOI)000472688800008 ()2-s2.0-85064954298 (Scopus ID)
Note

QC 20190715

Available from: 2019-07-15 Created: 2019-07-15 Last updated: 2019-07-29Bibliographically approved
Ahola, A., Bjork, T. & Barsoum, Z. (2019). Fatigue strength capacity of load-carrying fillet welds on ultra-high-strength steel plates subjected to out-of-plane bending. Engineering structures, 196, Article ID UNSP 109282.
Open this publication in new window or tab >>Fatigue strength capacity of load-carrying fillet welds on ultra-high-strength steel plates subjected to out-of-plane bending
2019 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 196, article id UNSP 109282Article in journal (Refereed) Published
Abstract [en]

Weld root fatigue strength capacity is an important design criterion in load-carrying (LC) fillet welded joints subjected to cyclic loads. This paper elaborates on the weld root fatigue strength capacity of fillet welded LC joints made of ultra-high-strength steel (UHSS) and subjected to out-of-plane bending. Experimental fatigue tests are carried out using constant amplitude loading with an applied stress ratio of R = 0.1 with both pure axial, i.e. DOB = 0 (degree of bending, bending stress divided by total stress) and bending, i.e. DOB = 1.0, load conditions. The applicability of different approaches - nominal weld stress, effective notch stress concepts, and 2D linear elastic fracture mechanics (LEFM) - for the fatigue strength assessment of weld root capacity is evaluated. Furthermore, a parametric LEFM analysis is used to evaluate the effect of weld penetration on the root fatigue strength capacity in axial and bending loading. The results indicate that in the case of bending, nominal weld stress can be calculated using the linear stress distribution over the joint section and FAT36 as a reference curve. In the bending loading, for the joints failing from the weld toe, a mean fatigue strength of up to 185 MPa in the nominal stress system was achieved, indicating that the reference curve FAT63 is overly conservative. The ENS concept with FAT225 seemed to be slightly unconservative for assessing the root fatigue strength capacity. LEFM analyses revealed that in the case of increasing weld penetration and bending loading, weld root fatigue strength capacity seemed to correlate with the nominal weld stress calculated using effective weld throat thickness, while in axial loading, weld stress should be calculated using external throat thickness summed with penetration length.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Fatigue assessment, Welded joints, Weld root fatigue strength, Bending, Ultra-high-strength steel, Load-carrying joint
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-259412 (URN)10.1016/j.engstruct.2019.109282 (DOI)000482518700008 ()2-s2.0-85067085616 (Scopus ID)
Note

QC 20190924

Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-09-24Bibliographically approved
Afshari, D., Mirzaahamdi, S. & Barsoum, Z. (2019). Residual Stresses in Resistance Spot Welded AZ61 Mg Alloy. CMES - Computer Modeling in Engineering & Sciences, 118(2), 275-290
Open this publication in new window or tab >>Residual Stresses in Resistance Spot Welded AZ61 Mg Alloy
2019 (English)In: CMES - Computer Modeling in Engineering & Sciences, ISSN 1526-1492, E-ISSN 1526-1506, Vol. 118, no 2, p. 275-290Article in journal (Refereed) Published
Abstract [en]

The use of magnesium alloys has been rapidly increased due to their ability to maintain high strengths at light weights. However weldability of steels and aluminum alloys by using resistance spot weld (RSW) process is a major issue, because it cannot be directly utilized for magnesium alloys. In this study, a structural-thermal-electrical finite element (FE) model has been developed to predict the distribution of residual stresses in RSW AZ61 magnesium alloy. Thermophysical and thermomechanical properties of AZ61 magnesium alloy have been experimentally determined, and have been used in FE model to increase the accuracy of the model. X-ray diffraction (XRD) technique has been utilized to measure the residual stresses in welded samples, and its results have been used to validate the FE model. Comparison study shows that the results obtained by using FE model have a good agreement with the experimental XRD data. In specific, the results show that the maximum tensile residual stress occurs at the weld center while decreases towards the nugget edge. In addition, the effects of welding parameters such as electrical current, welding time, and electrode force have been investigated on the maximum tensile residual stress. The results show that the tensile residual stress in welded joints rises by increasing the electrical current; however, it declines by prolonging the welding time as well as increasing the electrode force.

Place, publisher, year, edition, pages
TECH SCIENCE PRESS, 2019
Keywords
Resistance spot weld, AZ61 mg alloy, residual stresses, finite element model, x-ray diffraction
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-246293 (URN)10.31614/cmes.2019.03880 (DOI)000459391600002 ()2-s2.0-85063015035 (Scopus ID)
Note

QC 20190325

Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-05-13Bibliographically approved
Barsoum, I., Barsoum, Z. & Islam, M. D. (2019). Thermomechanical Evaluation of the Performance and Integrity of a HDPE Stub-End Bolted Flange Connection. Journal of Pressure Vessel Technology-Transactions of the ASME, 141(5), Article ID 051206.
Open this publication in new window or tab >>Thermomechanical Evaluation of the Performance and Integrity of a HDPE Stub-End Bolted Flange Connection
2019 (English)In: Journal of Pressure Vessel Technology-Transactions of the ASME, ISSN 0094-9930, E-ISSN 1528-8978, Vol. 141, no 5, article id 051206Article in journal (Refereed) Published
Abstract [en]

In this study, the integrity of a manhole structure made of a 78 in. high density polyethylene (HDPE) stub-end, steel ring, and blind flange, sealed with a compressed nonasbestos fiber (CNAF) gasket is investigated by means of a parametric finite element analysis (FEA). A coupled thermomechanical nonlinear FEA model is built, comprising of a heat transfer and a structural model, which allows modeling the complex thermal and mechanical loads and their interactions present during the operation of the manhole. The temperature-dependent elastic-plastic HDPE material constitutive behavior and the temperature-dependent nonlinear response of the CNAF gasket are accounted for in the model. Factors influencing the performance and integrity of the manhole such as stud-bolt pretorque level (T-b), internal pressure (P-i), and outer temperature (T-o) are considered. Based on the results, the integrity and performance of the structure are assessed in view of a leakage through the gasket criterion and a yielding of the HDPE stub-end criterion. The FEA results reveal that both T-b, P-i, and T-o significantly influence the performance (i.e., leakage) of the gasket and the integrity (i.e., yielding) of the HDPE stubend. At 40 degrees C, it is possible to find a safe operational window for a range of T-b and P-i values, where no leakage through the gasket or yielding of the stub-end occurs. However, as the temperature is increased this safe operational window decreases considerably, and at 80 degrees C safe operation cannot be guaranteed where leakage, yielding, or both simultaneously, will lead to loss in performance and integrity of the manhole structure.

Place, publisher, year, edition, pages
ASME, 2019
Keywords
HDPE, bolted flange, stub-end, gasket, finite element analysis, leakage, yielding, failure assessment chart
National Category
Vehicle Engineering
Research subject
Vehicle and Maritime Engineering
Identifiers
urn:nbn:se:kth:diva-261297 (URN)10.1115/1.4043844 (DOI)000485710100007 ()2-s2.0-85069147256 (Scopus ID)
Note

QC 20191008

Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2019-11-26Bibliographically approved
Umer, R., Barsoum, Z., Jishi, H. Z., Ushijima, K. & Cantwell, W. J. (2018). Analysis of the compression behaviour of different composite lattice designs. Journal of composite materials, 52(6), 715-729
Open this publication in new window or tab >>Analysis of the compression behaviour of different composite lattice designs
Show others...
2018 (English)In: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793X, Vol. 52, no 6, p. 715-729Article in journal (Refereed) Published
Abstract [en]

Four all-composite lattice designs were produced using a lost-mould procedure that involved inserting carbon fibre tows through holes in a core. Following resin infusion and curing, samples were heated to melt the core, leaving well-defined lattice structures based on what are termed BCC, BCCz, FCC and F2BCC designs. Analytical and numerical models for predicting the mechanical properties of the four designs are presented and these results are compared with the experimental data from the quasi-static compression tests. Compression tests on the four lattice structures indicated that the F2BCC lattice offered the highest compression strength, although when normalized by relative density, the BCCz lattice structure out-performed other structures. Similarly, the specific compression strengths were found to be superior to those of more traditional core materials. A number of failure mechanisms were also highlighted, including strut buckling, fracture at the strut-skin joints and debonding of reinforcing members at the central nodes. Finally, it is believed that the properties of these lattices can be further increased using higher fibre volume fractions.

Place, publisher, year, edition, pages
Sage Publications, 2018
Keywords
Lattice structures, sandwich cores, compression, lightweight structures
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-226806 (URN)10.1177/0021998317714531 (DOI)000429865700001 ()2-s2.0-85042867817 (Scopus ID)
Note

QC 20180508

Available from: 2018-05-08 Created: 2018-05-08 Last updated: 2018-06-04Bibliographically approved
Shams-Hakimi, P., Zamiri, F., Al-Emrani, M. & Barsoum, Z. (2018). Experimental study of transverse attachment joints with 40 and 60 mm thick main plates, improved by high-frequency mechanical impact treatment (HFMI). Engineering structures, 155, 251-266
Open this publication in new window or tab >>Experimental study of transverse attachment joints with 40 and 60 mm thick main plates, improved by high-frequency mechanical impact treatment (HFMI)
2018 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 155, p. 251-266Article in journal (Refereed) Published
Abstract [en]

In recent years, high-frequency mechanical impact (HFMI) treatment has grown in popularity due to its efficiency in improving the fatigue strength of welded joints. The fatigue performance of HFMI-treated welded steel joints has, however, not been thoroughly studied for plate thicknesses above 30 mm. In this study, 40 and 60 mm thick main plates with non-load-carrying transverse attachments have been fatigue tested under constant amplitude four-point bending, both in as-welded and HFMI-treated condition to investigate the fatigue performance for large plate thicknesses, typical for weldments in bridges. Axial fatigue strengths were estimated by a modification of the experimental results with fracture mechanics calculations. The main conclusions are that HFMI treatment can result in significant fatigue strength improvement even for large main plate thicknesses and that the difference in fatigue strength between bending and axial loading is negligible for the specimen geometries used in this study.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2018
Keywords
Fatigue, Thickness, HFMI, LEFM, Steel
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-221931 (URN)10.1016/j.engstruct.2017.11.035 (DOI)000419409800020 ()2-s2.0-85034604870 (Scopus ID)
Note

QC 20180131

Available from: 2018-01-31 Created: 2018-01-31 Last updated: 2018-01-31Bibliographically approved
Barsoum, Z., Stenberg, T. & Lindgren, E. (2018). Fatigue properties of cut and welded high strength steels-Quality aspects in design and production. In: Procedia Engineering: . Paper presented at 7th International Conference on Fatigue Design, Fatigue Design 2017, Senlis, France, 29 November 2017 through 30 November 2017 (pp. 470-476). Elsevier, 213
Open this publication in new window or tab >>Fatigue properties of cut and welded high strength steels-Quality aspects in design and production
2018 (English)In: Procedia Engineering, Elsevier, 2018, Vol. 213, p. 470-476Conference paper, Published paper (Refereed)
Abstract [en]

In this study, several aspects regarding effect of quality on the fatigue strength in welded cut HSS have been investigated and are discussed. A novel numerical algorithm has been developed which assesses the welded surface and calculates and quantifies weld quality parameters and the presence of defects which are critical in fatigue applications. The algorithm is designed for implementation in serial production. It will provide robust and reliable feedback on the quality being produced, which is essential if high strength steels are utilized and high quality welds are necessary for the structural integrity of the welded component. Two welding procedures which can increase the weld quality in as welded conditions have been assessed. It was found that by using these methods, the fatigue strength can be increased with 20% compared to normal weld quality. Furthermore, two fatigue assessment methods ability to account for increased weld quality in low cycle and high cycle fatigue applications has been studied. One of these methods showed sufficient accuracy in predicting the fatigue strength with small scatter and also account for increased weld quality. The influence of surface quality on cut edges was studied and the fatigue strength was estimated using international standards and a fatigue strength model for cut edges. It was found that the fatigue strength in testing was 15-70% higher compared to the estimation, thus proving a weak link between the international standard and fatigue strength.

Place, publisher, year, edition, pages
Elsevier, 2018
Series
Procedia Engineering, ISSN 1877-7058 ; 213
Keywords
Fatigue, high strength steel, quality, welded joints
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-228579 (URN)10.1016/j.proeng.2018.02.046 (DOI)000468155800045 ()2-s2.0-85047097393 (Scopus ID)
Conference
7th International Conference on Fatigue Design, Fatigue Design 2017, Senlis, France, 29 November 2017 through 30 November 2017
Note

QC 20180528

Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2019-10-23Bibliographically approved
Yalchiner, F. B. & Barsoum, Z. (2017). Life Extension of Welded Structures Using HFMI Techniques - Potential Application to Offshore Structures. In: Iacoviello, F Moreira, PMGP Tavares, PJS (Ed.), 2nd International Conference on Structural Integrity, ICSI 2017: . Paper presented at 2nd International Conference on Structural Integrity (ICSI), SEP 04-07, 2017, Funchal, Portugal (pp. 377-384). Elsevier, 5
Open this publication in new window or tab >>Life Extension of Welded Structures Using HFMI Techniques - Potential Application to Offshore Structures
2017 (English)In: 2nd International Conference on Structural Integrity, ICSI 2017 / [ed] Iacoviello, F Moreira, PMGP Tavares, PJS, Elsevier, 2017, Vol. 5, p. 377-384Conference paper, Published paper (Refereed)
Abstract [en]

Fatigue damage development in welded structures is a local phenomenon and if one need to achieve an extension of the life for the structure local post weld improvements need to be use in order to reduce/remove local features which contribute to the fatigue damage. In order to enhance the life time of load carrying welded structures without large amount of cost investments, e.g. redesign and replacement of existing structures, post weld improvement techniques need to be more applied. New High Frequency Mechanical Impact (HFMI) technologies have been developed in the last 10 years which enables cost-effective life extension and reparation of welded structures. The use improvement techniques for technical life enhancement upgrade and repair of welded structures within various industries, e.g. oil and gas, have been an accepted practice. HFMI treatment techniques are based on localized peening process of the welded joints and the devices are portable. The impacting results in a local cold plastic deformation which remove weld defects reduce stress concentration and induce compressive residual stresses which eventually will enhance the fatigue life of the welded structure. An overview of existing improvement techniques for welded structures is given followed by description of new technologies (HFMI). A brief description of the new international guideline and design recommendations within the International Institute of Welding (IIW) is given. Several validation studies on the fatigue performance of HFMI techniques are presented and onsite potential applications of the techniques for joints in fixed offshore structures are outlined.

Place, publisher, year, edition, pages
Elsevier, 2017
Series
Procedia Structural Integrity, ISSN 2452-3216 ; 5
Keywords
Life extension, HFMI (High Frequency Mechanical Impact), Welded Structure, Fatigue
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-221406 (URN)10.1016/j.prostr.2017.07.185 (DOI)000419177800050 ()
Conference
2nd International Conference on Structural Integrity (ICSI), SEP 04-07, 2017, Funchal, Portugal
Note

QC 20180117

Available from: 2018-01-17 Created: 2018-01-17 Last updated: 2018-01-29Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-4180-4710

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