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Publications (10 of 143) Show all publications
dell'Isola, F., Manzari, L., Göransson, P. & Hayat, T. (2019). Advances in pantographic structures: design, manufacturing, models, experiments and image analyses. Continuum Mechanics and Thermodynamics, 31(4), 1231-1282
Open this publication in new window or tab >>Advances in pantographic structures: design, manufacturing, models, experiments and image analyses
2019 (English)In: Continuum Mechanics and Thermodynamics, ISSN 0935-1175, E-ISSN 1432-0959, Vol. 31, no 4, p. 1231-1282Article in journal (Refereed) Published
Abstract [en]

In the last decade, the exotic properties of pantographic metamaterials have been investigated and different mathematical models (both discrete or continuous) have been introduced. In a previous publication, a large part of the already existing literature about pantographic metamaterials has been presented. In this paper, we give some details about the next generation of research in this field. We present an organic scheme of the whole process of design, fabrication, experiments, models and image analyses.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Pantographic structures, Additive manufacturing, Tomography, Generalized continua, Digital image correlation
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-255572 (URN)10.1007/s00161-019-00806-x (DOI)000475788200020 ()2-s2.0-85065039344 (Scopus ID)
Note

QC 20190805

Available from: 2019-08-05 Created: 2019-08-05 Last updated: 2019-08-05Bibliographically approved
Laudato, M., Di Cosmo, F., Drobnicki, R. & Göransson, P. (2019). Dynamical Vector Fields on Pantographic Sheet: Experimental Observations.. In: Abali, Bilen Emek; Altenbach, Holm; dell’Isola, Francesco; Eremeyev, Victor A.; Öchsner, Andreas (Ed.), New Achievements in Continuum Mechanics and Thermodynamics: Advanced Structured Materials (pp. 257-269). Springer International Publishing
Open this publication in new window or tab >>Dynamical Vector Fields on Pantographic Sheet: Experimental Observations.
2019 (English)In: New Achievements in Continuum Mechanics and Thermodynamics: Advanced Structured Materials / [ed] Abali, Bilen Emek; Altenbach, Holm; dell’Isola, Francesco; Eremeyev, Victor A.; Öchsner, Andreas, Springer International Publishing , 2019, p. 257-269Chapter in book (Other academic)
Abstract [en]

In this work, we will present and discuss some experimental observations of the dynamical displacement vector field on a pantographic sheet. We will sketch the experimental setup and we will qualitatively describe the observed behavior for a set of relevant frequencies.

Place, publisher, year, edition, pages
Springer International Publishing, 2019
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-248979 (URN)10.1007/978-3-030-13307-8_19 (DOI)2-s2.0-85063739657 (Scopus ID)
Note

QC 20190514

Available from: 2019-04-10 Created: 2019-04-10 Last updated: 2019-08-07Bibliographically approved
Göransson, P., Cuenca, J. & Lähivaara, T. (2019). Parameter estimation in modelling frequency response of coupled systems using a stepwise approach. Mechanical systems and signal processing, 126, 161-175
Open this publication in new window or tab >>Parameter estimation in modelling frequency response of coupled systems using a stepwise approach
2019 (English)In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 126, p. 161-175Article in journal (Refereed) Published
Abstract [en]

This paper studies the problem of parameter estimation in resonant, acoustic fluid-structure interaction problems over a wide frequency range. Problems with multiple resonances are known to be subjected to local minima, which represents a major challenge in the field of parameter identification. We propose a stepwise approach consisting in subdividing the frequency spectrum such that the solution to a low-frequency subproblem serves as the starting point for the immediately higher frequency range. In the current work, two different inversion frameworks are used. The first approach is a gradient-based deterministic procedure that seeks the model parameters by minimising a cost function in the least squares sense and the second approach is a Bayesian inversion framework. The latter provides a potential way to assess the validity of the least squares estimate. In addition, it presents several advantages by providing invaluable information on the uncertainty and correlation between the estimated parameters. The methodology is illustrated on synthetic measurements with known design variables and controlled noise levels. The model problem is deliberately kept simple to allow for extensive numerical experiments to be conducted in order to investigate the nature of the local minima in full spectrum analyses and to assess the potential of the proposed method to overcome these. Numerical experiments suggest that the proposed methods may present an efficient approach to find material parameters and their uncertainty estimates with acceptable accuracy.

Keywords
Parameter identification, Fluid-solid interaction, Deterministic framework, Bayesian framework, Uncertainty quantification
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-244474 (URN)10.1016/j.ymssp.2019.02.014 (DOI)000465060800009 ()2-s2.0-85061795796 (Scopus ID)
Funder
Vinnova
Note

QC 20190228

Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2019-05-14Bibliographically approved
Manzari, L., Göransson, P., Cuenca, J. & Lopez Arteaga, I. (2018). A fully automated high-speed optical rig for in vacuo, full field, non-contact vibration measurements for viscoelastic, anisotropic materials. In: : . Paper presented at NOVEM 2018 Noise and vibration emerging methods, The 6th conference, Ibiza (Balearic Islands), Spain, May 7-9, 2018 (pp. 91-102). , Article ID 175109.
Open this publication in new window or tab >>A fully automated high-speed optical rig for in vacuo, full field, non-contact vibration measurements for viscoelastic, anisotropic materials
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, a setup for measuring the three-dimensional displacement field of a test object un-dergoing controlled dynamic excitation in a vacuum chamber is presented. The setup has beendesigned with porous materials in mind, yet is suitable for the measurement of anisotropic vis-coelastic solids in general. To achieve non-contact data acquisition, a stereo high-speed camerasystem measures the displacement of the foundation and of the test object. A laser Doppler vi-brometer is used before the actual measurement to choose an excitation level that maximizes thesignal-to-noise ratio while allowing to ensure that the test object is fully relaxed and stable at thebeginning of every measurement. The setup, comprising both commercial and in-house hardwareand software solutions, addresses the challenges of measuring in vacuum with non-contact tech-niques. All these aspects are discussed in the current paper, and preliminary results are presented.The ultimate objective is to estimate the dynamic properties of a material using inverse methodsand the data obtained.

Keywords
dic, non-contact, vibration, anisotropy, high-speed, digital image correlation, viscoelasticity
National Category
Mechanical Engineering
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-231576 (URN)
Conference
NOVEM 2018 Noise and vibration emerging methods, The 6th conference, Ibiza (Balearic Islands), Spain, May 7-9, 2018
Note

QC 20180702

Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-10-19Bibliographically approved
Rumpler, R., Rodriguez Sanchéz, R. & Göransson, P. (2018). A multivariate, well-conditioned asymptotic waveform evaluation for finite element solutions with complex parametric dependence. In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics: . Paper presented at ISMA-USD 2018.
Open this publication in new window or tab >>A multivariate, well-conditioned asymptotic waveform evaluation for finite element solutions with complex parametric dependence
2018 (English)In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics, 2018Conference paper, Published paper (Refereed)
Abstract [en]

Most engineering applications involving solutions by numerical methods are dependent on several parameters, whose impact on the solution may significantly vary from one to the other. At times an evaluation of these multivariate solutions may be required at the expense of a prohibitively high computational cost. In the present work, a multivariate finite element approach is proposed, allowing for a fast evaluation of parametric responses. It is based on the construction of a reduced basis spanning a subspace able to capture rough variations of the response. The method consists in an extension of the Well-Conditioned Asymptotic Waveform Evaluation (WCAWE) to multivariate problems, by an appropriate choice of derivative sequences, and a selection of the most relevant basis components. It is validated and demonstrated for its potential on a semi-industrial sized 3D application involving coupled poroelastic and internal acoustic domains.

National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-240278 (URN)2-s2.0-85060386599 (Scopus ID)
Conference
ISMA-USD 2018
Funder
Swedish Research Council, 2015-04925Vinnova, 2016-05195
Note

QC 20190109

Available from: 2018-12-14 Created: 2018-12-14 Last updated: 2019-05-20Bibliographically approved
Gaborit, M., Dazel, O. & Göransson, P. (2018). A simplified model for thin acoustic screens. Journal of the Acoustical Society of America, 144(1), EL76-EL81
Open this publication in new window or tab >>A simplified model for thin acoustic screens
2018 (English)In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 144, no 1, p. EL76-EL81Article in journal (Refereed) Published
Abstract [en]

A generalization of the commonly used pressure jump modeling of thin porous layers is proposed. The starting point is a transfer matrix model of the layer derived using matrix exponentials. First order expansions of the propagating terms lead to a linear approximation of the associated phenomena and the resulting matrix is further simplified based on physical assumptions. As a consequence, the equivalent fluid parameters used in the model may be reduced to simpler expressions and the transfer matrix rendered sparser. The proposed model is validated for different backing conditions, from normal to grazing incidence and for a wide range of thin films. In the paper, the physical hypotheses are discussed, together with the origin of the field jumps.

Place, publisher, year, edition, pages
Acoustical Society of America (ASA), 2018
National Category
Control Engineering
Identifiers
urn:nbn:se:kth:diva-233427 (URN)10.1121/1.5047929 (DOI)000440810900013 ()30075680 (PubMedID)2-s2.0-85051036767 (Scopus ID)
Note

Correction in DOI:10.1121/1.5121612 ISI:000483887400062

QC 20180821

Available from: 2018-08-21 Created: 2018-08-21 Last updated: 2019-09-30Bibliographically approved
Palma, G., Mao, H., Burghignoli, L., Göransson, P. & Iemma, U. (2018). Acoustic Metamaterials in Aeronautics. Applied Sciences, 8(6), Article ID 971.
Open this publication in new window or tab >>Acoustic Metamaterials in Aeronautics
Show others...
2018 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 8, no 6, article id 971Article in journal (Refereed) Published
Abstract [en]

Metamaterials, man-made composites that are scaled smaller than the wavelength, have demonstrated a huge potential for application in acoustics, allowing the production of sub-wavelength acoustic absorbers, acoustic invisibility, perfect acoustic mirrors and acoustic lenses for hyper focusing, and acoustic illusions and enabling new degrees of freedom in the control of the acoustic field. The zero, or even negative, refractive sound index of metamaterials offers possibilities for the control of acoustic patterns and sound at sub-wavelength scales. Despite the tremendous growth in research on acoustic metamaterials during the last decade, the potential of metamaterial-based technologies in aeronautics has still not been fully explored, and its utilization is still in its infancy. Thus, the principal concepts mentioned above could very well provide a means to develop devices that allow the mitigation of the impact of civil aviation noise on the community. This paper gives a review of the most relevant works on acoustic metamaterials, analyzing them for their potential applicability in aeronautics, and, in this process, identifying possible implementation areas and interesting metabehaviors. It also identifies some technical challenges and possible future directions for research with the goal of unveiling the potential of metamaterials technology in aeronautics.

Place, publisher, year, edition, pages
MDPI, 2018
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-232923 (URN)10.3390/app8060971 (DOI)000436488000130 ()2-s2.0-85048596943 (Scopus ID)
Note

QC 20180808

Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2018-08-08Bibliographically approved
Gaborit, M. M., Schwan, L., Dazel, O., Groby, J.-P. -., Weisser, T. & Göransson, P. (2018). Coupling FEM, bloch waves and TMM in meta poroelastic laminates. Acta Acoustica united with Acustica, 104(2), 220-227
Open this publication in new window or tab >>Coupling FEM, bloch waves and TMM in meta poroelastic laminates
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2018 (English)In: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, Vol. 104, no 2, p. 220-227Article in journal (Refereed) Published
Abstract [en]

The propagation of airborne plane waves in the presence of a meta poroelastic laminate, that is a poroelastic matrix coated with thin elastic layers at its facings and periodically-embedded with inclusions, is studied. Using the Finite Element Method (FEM) only would result in a drastic increase of the degrees of freedom due to the fine mesh required to account for the very thin coatings. Here, the approach relies on: The Bloch wave expansion of the fields in air; the modal Transfer Matrix Method to account for the coatings; and the coupling with the FEM model of the poroelastic matrix and the resonant inclusions. The model is developed for reflection and transmission problems and it can account for coatings with multiple layers. The procedure induces the addition of the Bloch coefficients in the FEM's linear system at a negligible additional computational cost. It is applied to the meta poroelastic laminates with poroelastic inclusions and rubber shell inclusions. The results are compared with those from the Multiple Scattering Theory and an excellent agreement between the methods is found. The approach offers a numerically-efficient way to account for coatings applied to meta poroelastic layers, and finds applications in industrial prototypes where coatings are widely used.

Place, publisher, year, edition, pages
S. Hirzel Verlag GmbH, 2018
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-224825 (URN)10.3813/AAA.919163 (DOI)000428258600005 ()2-s2.0-85043755972 (Scopus ID)
Note

QC 20180326

Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2018-05-16Bibliographically approved
Gaborit, M., Dazel, O., Göransson, P. & Gabard, G. (2018). Coupling of finite element and plane waves discontinuous Galerkin methods for time-harmonic problems. International Journal for Numerical Methods in Engineering, 116(7), 487-503
Open this publication in new window or tab >>Coupling of finite element and plane waves discontinuous Galerkin methods for time-harmonic problems
2018 (English)In: International Journal for Numerical Methods in Engineering, ISSN 0029-5981, E-ISSN 1097-0207, Vol. 116, no 7, p. 487-503Article in journal (Refereed) Published
Abstract [en]

A coupling approach is presented to combine a wave-based method to the standard finite element method. This coupling methodology is presented here for the Helmholtz equation but it can be applied to a wide range of wave propagation problems. While wave-based methods can significantly reduce the computational cost, especially at high frequencies, their efficiency is hampered by the need to use small elements to resolve complex geometric features. This can be alleviated by using a standard finite element model close to the surfaces to model geometric details and create large, simply-shaped areas to model with a wave-based method. This strategy is formulated and validated in this paper for the wave-based discontinuous Galerkin method together with the standard finite element method. The coupling is formulated without using Lagrange multipliers and results demonstrate that the coupling is optimal in that the convergence rates of the individual methods are maintained.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-239305 (URN)10.1002/nme.5933 (DOI)000446988200003 ()2-s2.0-85052440540 (Scopus ID)
Note

QC 20181120

Available from: 2018-11-19 Created: 2018-11-19 Last updated: 2018-12-11Bibliographically approved
Rice, H. J., Kennedy, J. & Göransson, P. (2018). Design of a Kelvin Cell Acoustic Metamaterial. In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics: . Paper presented at 28th International Conference on Noise and Vibration Engineering, ISMA 2018 and 7th International Conference on Uncertainty in Structural Dynamics, USD 2018; Leuven; Belgium; 17 September 2018 through 19 September 2018 (pp. 1081-1090). KU Leuven - Departement Werktuigkunde
Open this publication in new window or tab >>Design of a Kelvin Cell Acoustic Metamaterial
2018 (English)In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics, KU Leuven - Departement Werktuigkunde , 2018, p. 1081-1090Conference paper, Published paper (Refereed)
Abstract [en]

Advancements in 3D print technology now allows the printing of structured acoustic absorbent materials at appropriate microscopic scale and sample sizes. Optimisation of parameter sets associated with a Kelvin Cell structure have the potential to develop various metabehaviours in the associated acoustic responses. The repeatability of the fundamental cell unit also provide a route for the development of viable macro models to simulate built up structures based on detailed models of the individual cell units. This paper describes a process to model, print and test of such a sample. Manufacturing restraints will initially guide the optimised design. Micro to macro models based on a single cell structure which are cross checked against a full visco thermal acoustic finite element model of the individual cell. A macro model based on a reduced lossy helmholtz system is then used to predict the absorptive response response under normal incidence and checked against a manufactured sample under experimental test.

Place, publisher, year, edition, pages
KU Leuven - Departement Werktuigkunde, 2018
National Category
Fluid Mechanics and Acoustics
Research subject
Vehicle and Maritime Engineering
Identifiers
urn:nbn:se:kth:diva-240142 (URN)2-s2.0-85060385019 (Scopus ID)9789073802995 (ISBN)
Conference
28th International Conference on Noise and Vibration Engineering, ISMA 2018 and 7th International Conference on Uncertainty in Structural Dynamics, USD 2018; Leuven; Belgium; 17 September 2018 through 19 September 2018
Note

QC 20181214

Available from: 2018-12-13 Created: 2018-12-13 Last updated: 2019-03-27Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1855-5437

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