TY - GEN

T1 - Using the SEREP Idea for the Projection of Modal Coordinates to Different Finite Element Meshes

AU - Witteveen, Wolfgang

AU - Pöchacker, Stefan

AU - Pichler, Florian

PY - 2020

Y1 - 2020

N2 - Reduced order modelling is of crucial importance for the dynamics of complex Finite Element structures. Thereby the overall deformation state is approximated by a superposition of weighted trial vectors, commonly called modes. The weighting factors (‘modal coordinates’) are obtained by numerical time integration of the reduced order model. In case of complex systems, the time integration normally dominates the overall simulation time. A multibody simulation of a flexible crankshaft interacting with pistons, con rods, fly wheel, hydrodynamic bearings and furthers for instance, takes at least several hours of CPU time. The modal coordinates can then be used for modal stress recovery in order to predict the fatigue lifetime. If a variant of the flexible body with small changes needs to be investigated, a new numerical time integration is necessary. In this paper a method is proposed where the modal coordinates of a flexible body will be projected unto another mode base. This will be done by using the key idea of the SEREP method where the modal coordinates are computed via the Pseudo-Inverse. One academic and one industrial example demonstrate that the time integration of the variant can totally be skipped without remarkable loss of accuracy, as long as the differences between the two flexible bodies are small enough.

AB - Reduced order modelling is of crucial importance for the dynamics of complex Finite Element structures. Thereby the overall deformation state is approximated by a superposition of weighted trial vectors, commonly called modes. The weighting factors (‘modal coordinates’) are obtained by numerical time integration of the reduced order model. In case of complex systems, the time integration normally dominates the overall simulation time. A multibody simulation of a flexible crankshaft interacting with pistons, con rods, fly wheel, hydrodynamic bearings and furthers for instance, takes at least several hours of CPU time. The modal coordinates can then be used for modal stress recovery in order to predict the fatigue lifetime. If a variant of the flexible body with small changes needs to be investigated, a new numerical time integration is necessary. In this paper a method is proposed where the modal coordinates of a flexible body will be projected unto another mode base. This will be done by using the key idea of the SEREP method where the modal coordinates are computed via the Pseudo-Inverse. One academic and one industrial example demonstrate that the time integration of the variant can totally be skipped without remarkable loss of accuracy, as long as the differences between the two flexible bodies are small enough.

KW - Modal stress recovery

KW - Model reduction

KW - SEREP

UR - http://www.scopus.com/inward/record.url?scp=85068152509&partnerID=8YFLogxK

U2 - 10.1007/978-3-030-12243-0_5

DO - 10.1007/978-3-030-12243-0_5

M3 - Conference contribution

SN - 9783030122423

T3 - Conference Proceedings of the Society for Experimental Mechanics Series

SP - 27

EP - 30

BT - Special Topics in Structural Dynamics and Experimental Techniques, Volume 5 - Proceedings of the 37th IMAC, A Conference and Exposition on Structural Dynamics 2019

A2 - Dervilis, Nikolaos

PB - Springer

ER -