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Ekevid, Torbjörn
Publications (10 of 11) Show all publications
Danielsson, P.-O., Ekevid, T., Kumar, M., Tim, R. & Wilhelmsson, M. (2018). Articulated Hauler Load Simulations: Recent developments. In: Karsten Berns, Klaus Dressler, Patrick Fleischmann, Daniel Görges, Ralf Kalmar, Bernd Sauer, Nicole Stephan, Roman Teutsch, Martin Thul (Ed.), Commercial Vehicle Technology 2018: Proceedings of the 5th Commercial Vehicle Symposium - CVT 2018. Paper presented at Commercial Vehicle Technology 2018 (pp. 505-517). Heidelberg: Springer
Open this publication in new window or tab >>Articulated Hauler Load Simulations: Recent developments
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2018 (English)In: Commercial Vehicle Technology 2018: Proceedings of the 5th Commercial Vehicle Symposium - CVT 2018 / [ed] Karsten Berns, Klaus Dressler, Patrick Fleischmann, Daniel Görges, Ralf Kalmar, Bernd Sauer, Nicole Stephan, Roman Teutsch, Martin Thul, Heidelberg: Springer, 2018, p. 505-517Conference paper, Published paper (Refereed)
Abstract [en]

The paper presents recent method developments and activitiescarried out in the eld of load simulations and fatigue assessmentsat Volvo CE on the articulated hauler (AH) platform. Items discussedmore in details are hydraulic system simulation model improvements,road data scanning and usage of the virtual test tracks. Also the inertiarelief method for fatigue assessment without applying boundary conditionsin FEA is covered.

Results from ongoing hauler projects and model validation activities aredemonstrated and the results conrm that Multi Body Simulations canthe used for load predictions on the hauler platform. The simulationresults are in line with and show a similar behavior as tests.

Place, publisher, year, edition, pages
Heidelberg: Springer, 2018
Series
Proceedings PROCEE, ISSN 2198-7432
Keywords
Multi body simulations, co-simulation, articulated hauler, virtual loads
National Category
Vehicle Engineering
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-72036 (URN)10.1007/978-3-658-21300-8_39 (DOI)978-3-658-21299-5 (ISBN)978-3-658-21300-8 (ISBN)
Conference
Commercial Vehicle Technology 2018
Available from: 2018-06-07 Created: 2018-06-07 Last updated: 2019-05-23Bibliographically approved
Burger, M., Carlqvist, C., Ekevid, T., Steidel, S. & Weber, D. (2018). Multiphysics simulations of construction equipment: coupling material machine and power source. In: Berns, K., Dressler, K., Fleischmann, P., Görges, D., Kalmar, R., Sauer, B., Stephan, N., Teutsch, R. & Thul, M. (Ed.), Commercial Vehicle Technology 2018: Proceedings of the 5th Commercial Vehicle Technology Symposium - CVT 2018. Paper presented at 5th International Commercial Vehicle Technology Symposium Kaiserslautern, Germany, March 13-15, 2018 (pp. 481-492). Berlin: Springer, 1
Open this publication in new window or tab >>Multiphysics simulations of construction equipment: coupling material machine and power source
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2018 (English)In: Commercial Vehicle Technology 2018: Proceedings of the 5th Commercial Vehicle Technology Symposium - CVT 2018 / [ed] Berns, K., Dressler, K., Fleischmann, P., Görges, D., Kalmar, R., Sauer, B., Stephan, N., Teutsch, R. & Thul, M., Berlin: Springer, 2018, Vol. 1, p. 481-492Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Berlin: Springer, 2018
Series
Proceedings, E-ISSN 2198-7432
Keywords
Multi body simulations, co-simulations, wheel loader
National Category
Vehicle Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering; Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-72034 (URN)978-3-658-21299-5 (ISBN)978-3-658-21300-8 (ISBN)
Conference
5th International Commercial Vehicle Technology Symposium Kaiserslautern, Germany, March 13-15, 2018
Available from: 2018-03-29 Created: 2018-03-29 Last updated: 2018-04-11Bibliographically approved
Matthias, B., Burger, M., Dauwel, T., Ekevid, T., Steidel, S. & Weber, D. (2016). Coupling DEM Particles to MBS Wheel Loader via Co-Simulation. In: K. Berns, K. Dreßler, P. Fleischmann, R. Ilsen, B. Jörg, R. Kalmar, T. Nagel, C. Schindler, N. K. Stephan (Ed.), Proceedings of the 4th Commercial Vehicle Technology Symposium (CVT 2016): . Paper presented at 4th International Commercial Vehicle Technology Symposium. Kaiserslautern: Shaker Verlag
Open this publication in new window or tab >>Coupling DEM Particles to MBS Wheel Loader via Co-Simulation
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2016 (English)In: Proceedings of the 4th Commercial Vehicle Technology Symposium (CVT 2016) / [ed] K. Berns, K. Dreßler, P. Fleischmann, R. Ilsen, B. Jörg, R. Kalmar, T. Nagel, C. Schindler, N. K. Stephan, Kaiserslautern: Shaker Verlag, 2016Conference paper, Published paper (Refereed)
Abstract [en]

A co-simulation scheme is developed that couples an MBS wheel loader model with the ITWM/DEM code for soil simulation, in order to realize a framework in which different loading maneuvers can be simulated and analyzed. An important issue for such analyses is to provide reaction forces during digging and loading that are sufficiently accurate to address questions of durability and energy efficiency. We present the coupling strategy, the coupled simulation approach as well as its realization that has been evolved during a project collaboration between the Fraunhofer ITWM and Volvo CE.

Place, publisher, year, edition, pages
Kaiserslautern: Shaker Verlag, 2016
Keywords
DEM, MBS, Vehicle dynamics
National Category
Vehicle Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-65054 (URN)978-3-8440-4229-0 (ISBN)
Conference
4th International Commercial Vehicle Technology Symposium
Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2017-06-09Bibliographically approved
Ekevid, T., Carlqvist, C. & Sjödén, T. (2015). Virtual Articulated Haulers: prediction of vehicle performance and design loads. In: Josep M. Font-Llagunes (Ed.), Multibody Dynamics 2015: Barcelona, June 29 – July 2. Paper presented at ECCOMAS Thematic Conference on Multibody Dynamics June 29 - July 2, 2015, Barcelona, Catalonia, Spain (pp. 1377-1387). Barcelona: International Center for Numerical Methods in Engineering (CIMNE)
Open this publication in new window or tab >>Virtual Articulated Haulers: prediction of vehicle performance and design loads
2015 (English)In: Multibody Dynamics 2015: Barcelona, June 29 – July 2 / [ed] Josep M. Font-Llagunes, Barcelona: International Center for Numerical Methods in Engineering (CIMNE), 2015, p. 1377-1387Conference paper, Published paper (Refereed)
Abstract [en]

Articulated haulers are suited for any kind of transports in difficult terrain. The concept was developed from an agricultural tractor in the 1960’s by Volvo. The main features are the hydraulic steering, the individual front and rear frames connected with a rotational hitch joint, all-wheel drive and large tires. These features give the extraordinary terrain capability. Complete vehicle simulations support development of stability, handling and ride comfort properties during early development of the hauler. Complete vehicle simulations can also be utilized to extract design loads. This paper presents the current status in this field.

The complete vehicle MBS simulation model includes flexible bodies, hydraulic system, tires and powertrain. A refined powertrain model in Simulink is used for the analysis presented. The environment is defined by the road and the driver. A comfort track road is used for comfort evaluations and a digitalized endurance test road for load predictions. The driver model aims to follow the given target path and velocity.

Simulation and measurement signals are compared by means of relevant spectra; load ranges, level crossings and Power Spectral Density. A scalar measure is defined by the equivalent value to carry out comparisons between simulations and test. Fatigue load simulations need an accurate dynamic description of the vehicle, capturing low frequency excitation. The results shows that the load simulation captures the frequency peaks below 15 Hz, although there are some differences in magnitude and peak frequency. When simulated and measured equivalent values are compared most entities are in the range between 1/2 and 2 regarding estimated life. Further improvements are possible but the simulated load quality should also be related to other uncertainties in the fatigue evaluation process.

Place, publisher, year, edition, pages
Barcelona: International Center for Numerical Methods in Engineering (CIMNE), 2015
Keywords
Articulated Hauler, Co-simulation, Structure loads, Multi Body Dynamics
National Category
Vehicle Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-45690 (URN)978-84-944244-0-3 (ISBN)
Conference
ECCOMAS Thematic Conference on Multibody Dynamics June 29 - July 2, 2015, Barcelona, Catalonia, Spain
Available from: 2015-08-14 Created: 2015-08-14 Last updated: 2018-05-18Bibliographically approved
Bolmsvik, Å., Linderholt, A., Brandt, A. & Ekevid, T. (2014). FE Modelling of Light Weight Wooden Assemblies: parameter study and comparison between analyses and experiments. Engineering structures, 73, 125-142
Open this publication in new window or tab >>FE Modelling of Light Weight Wooden Assemblies: parameter study and comparison between analyses and experiments
2014 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 73, p. 125-142Article in journal (Refereed) Published
Abstract [en]

A finite element (FE) analysis of a model representing a mock-up structure previously investigated experimentally is investigated in this study. The aim is to make a correlation and calibration between test and analysis of the full scale wooden structure; both eigenmodes and acceleration levels are compared. Large scatter is found in material properties used for light weight wooden structures in literature. In this study, a parameter evaluation is therefore made to show how different properties influence the dynamic behaviour of the structure. It is shown that the wood beam material properties influence the behaviour of the light weight wooden structure FE model most.

Two types of junctions are modelled and evaluated; a tied connection is used to simulate screwed junctions and spring/dashpot elements are used to represent elastomer junctions between the floor and the walls. The springs and dashpots used to model the elastomer in the junction work well in the bearing direction but need to be improved to obtain correct rotational stiffness, shear motion and friction. There are still many unknown parameters in a complex wooden structure that remain to be investigated. However, the results presented in this paper add data to be used for FE modelling of a complex wooden structure.

Place, publisher, year, edition, pages
Elsevier, 2014
Keywords
Finite Element Model Vibrational Test Correlation
National Category
Building Technologies
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-34219 (URN)10.1016/j.engstruct.2014.04.028 (DOI)000338812000011 ()2-s2.0-84901339208 (Scopus ID)
Available from: 2014-05-18 Created: 2014-05-18 Last updated: 2017-12-05Bibliographically approved
Bolmsvik, Å. & Ekevid, T. (2010). FE modeling of wooden building assemblies. In: InterNoise 2010-Lisbon Portugal 13-16 June: . Paper presented at Inter.Noise 2010, 13-16 June, Lisbon (pp. 1-10).
Open this publication in new window or tab >>FE modeling of wooden building assemblies
2010 (English)In: InterNoise 2010-Lisbon Portugal 13-16 June, 2010, p. 1-10Conference paper, Oral presentation only (Refereed)
Abstract [en]

Residential timber framed buildings have in some cases received complaints from inhabitants due to structure-borne sound at low frequencies, even if the building meets the regulations with respect to impact sound quality. This paper describes FE-analyses to evaluate the test setups of a building assembly and to prepare for the full-scale experimental modal analysis planned. By modal analysis, the dynamic properties of a structure, such as eigen modes and damping characteristics, can be extracted.

 

The test assembly consists of prefabricated wall and floor/roof timber elements. Different assembly and joining methods as well as building element are used. The eigen modes and damping differs between the assemblies investigated which influence the dynamic response in the lower frequencies. The results are carefully evaluated and planned measurements are discussed.

Keywords
Structure-borne sound, modal analysis, dynamic response, FE analysis
National Category
Fluid Mechanics and Acoustics Building Technologies
Identifiers
urn:nbn:se:lnu:diva-24561 (URN)
Conference
Inter.Noise 2010, 13-16 June, Lisbon
Available from: 2013-03-04 Created: 2013-02-25 Last updated: 2015-09-17Bibliographically approved
Svahn, P.-O., Ekevid, T. & Runesson, K. (2007). Discrete crack modelling in a new X-FEM format with emphasis on dynamic response. International Journal for Numerical and Analytical Methods in Geomechanics, 31(2), 261-283
Open this publication in new window or tab >>Discrete crack modelling in a new X-FEM format with emphasis on dynamic response
2007 (English)In: International Journal for Numerical and Analytical Methods in Geomechanics, ISSN 0363-9061, Vol. 31, no 2, p. 261-283Article in journal (Refereed) Published
Abstract [en]

The displacement field in quasi-brittle material is localized into narrow fracture zones during the process of decohesion. The numerical modelling of the physically propagating displacement discontinuities is considered to be inherently difficult. In this paper, the introduction of continuous discontinuities into the finite element formulation is based on the extended finite element method (X-FEM). This paper extends the theory by further incorporating arbitrary discontinuities in the approximation and presenting numerical procedures to handle several fields of discontinuities. The discontinuous approximation is accomplished by usage of basis functions of very limited support; only non-zero in the elements containing the crack. Moreover, the introduction of discontinuities in a continuum is discussed and a robust numerical procedure is proposed. Further, the mechanical behaviour of cracks in a quasi-brittle material largely governs the overall mechanical response of the material, and the implementation of a cohesive crack model based on anisotropic damage coupled to plasticity is emphasized. Numerical examples for both static and dynamic, transient, loading show that the proposed X-FEM format in combination with the cohesive crack model has a good performance and leads to an efficient implementation. Finally, the proposed forward method for propagation of cracks and introduction of new ones is robust and stable.

Place, publisher, year, edition, pages
John Wiley and Sons Ltd, 2007
Keywords
extended finite element method, partition of unity, anisotropic damage, plasticity, rate dependency, crack, quasi-brittle, concrete, softening, interface, constitutive models
National Category
Mechanical Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:vxu:diva-4502 (URN)10.1002/nag.56 (DOI)
Available from: 2007-05-03 Created: 2007-05-03 Last updated: 2017-10-12Bibliographically approved
Lane, H., Ekevid, T., Kettil, P., Ching, R. & Wiberg, N.-E. (2006). Adaptive multigrid for full scale railway dynamics. In: International Conference on Computational and Applied Mathematics.
Open this publication in new window or tab >>Adaptive multigrid for full scale railway dynamics
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2006 (English)In: International Conference on Computational and Applied Mathematics, 2006Conference paper, Published paper (Other academic)
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:vxu:diva-4504 (URN)
Available from: 2007-05-03 Created: 2007-05-03 Last updated: 2010-03-10Bibliographically approved
Ekevid, T., Lane, H. & Wiberg, N.-E. (2006). Adaptive solid wave propagation: Influences of boundary conditions in high-speed train applications. Computer Methods in Applied Mechanics and Engineering, 195(4-6), 236-250
Open this publication in new window or tab >>Adaptive solid wave propagation: Influences of boundary conditions in high-speed train applications
2006 (English)In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, Vol. 195, no 4-6, p. 236-250Article in journal (Refereed) Published
Abstract [en]

Wave propagation in solid materials is of great interest in many engineering applications. The fact that the area of interest changes with time creates a number of computational problems such as the need for a mesh density varying in space and time. This means that the mesh must be continuously updated and controlled, rendering a large demand of computer effort. In certain applications like railway mechanics there are mobile loads. A load speed close to the natural speed in the underlying soil causes specific problems, shock waves being one of them. The transmitted waves have to leave the defined finite element domain without reflection, which imposes a need for certain modelling methods. The paper will deal with quality controlled FE-procedures for wave propagation including error estimation and mesh refinement/coarsening. As an application an important problem from railway mechanics is considered. When a high-speed train approaches an area with decreasing thickness of underlying soft soil on a stiff rock it is expected that the reflection of the wave will increase the total amplitude of the wave. We will study this problem with the procedures described above in full 3D with partly absorbing boundaries

Place, publisher, year, edition, pages
Elsevier, 2006
Keywords
Wave propagation, Hybrid method, Absorbing boundaries, Adaptivity
National Category
Other Materials Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:vxu:diva-4463 (URN)
Available from: 2006-04-26 Created: 2006-04-26 Last updated: 2010-03-10Bibliographically approved
Ekevid, T., Kettil, P., Lane, H. & Wiberg, N.-E. (2006). Computational railway dynamics. In: European Congress on Computational Mechanics. ECCOMAS
Open this publication in new window or tab >>Computational railway dynamics
2006 (English)In: European Congress on Computational Mechanics, ECCOMAS , 2006Conference paper, Published paper (Refereed)
Abstract [en]

To understand the physical phenomena and to be able to propose countermeasures/improvements, simulation tools to perform computations of the entire dynamical system including subground, track structure and the train have been developed. In particular, effort has been devoted to the special wave propagation problem related to high-speed trains running at soft ground materials. As the speed of the train approaches and exceeds the natural (Rayleigh) wave propagation velocity of the ground material, shock waves similar to a sonic boom originate from the onrushing train. The problem area contains several computational challenges since it implies efficient techniques to handle time integration of large-scale problems, infinite domains, non-linear material response etc.

Efficient solvers based on a combination of multigrid, error estimations and adaptive refinement have been developed to reach acceptable execution times. The solution time is substantially reduced compared to conventional implicit solvers based on factorization. Moreover, an indefinite system from the Lagrange multiplier approach to handle constraint equations requires additional preconditioning to guarantee convergence and reduce the number of iterations.

In the paper a number of numerical examples from railway applications are presented. Results from computation where the train is represented as a collection of moving loads as well as a multi body system with complete train-track interaction are demonstrated.

Place, publisher, year, edition, pages
ECCOMAS, 2006
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:vxu:diva-4503 (URN)1-4020-4978-1 (ISBN)
Available from: 2007-05-03 Created: 2007-05-03 Last updated: 2010-03-10Bibliographically approved
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