Efficient impact analysis using reduced flexible multibody systems and contact submodels
European Conference on Computational Mechanics: Solids, Structures and Coupled Problems, ECCM and 7th European Conference on Computational Fluid Dynamics, ECFD: 2711-2722 (2018-06)
For an efficient and accurate analysis of impact problems reduced flexible multibody systems can be used. Therefore, a precise reproduction of the wave propagation in the colliding bodies as well as contact forces and stresses are required. To capture all mentioned phenomena precisely, a set of eigenmodes and static shape functions has to be used for the elastic description of the flexible bodies. While the eigenmodes represent the global deformations, and therefore are physically important, the static shape functions are only necessary to capture the local deformations. Hence, their very high eigenfrequencies are artificially generated and additionally increase the numerical stiffness of the system. As a result of that, the numerical efficiency may decrease. In the present paper, two approaches for an efficient contact simulation in reduced flexible multibody simulations using static shape functions are presented. Both approaches are based on the subdivision of the elastic parts of the equations of motion in low and high frequency parts. The first approach uses modal damping on the high frequency parts. The second approach treats the high frequency parts quasi-statically and so they can be neglected in the dynamic simulation. The focus is on numerical stiff systems with a large number of static shape functions simultaneously loaded. Comparisons are made between reduced flexible multibody systems using the proposed approaches and full non-linear finite element simulations.
Flexible Multibody Systems