Curb Impact: Non-linear structural FE analyses in Multibody Dynamics Models

In a few extreme customer abuse load cases such as Curb Impact and Potholes, automotive structures see non-linear (plastic) deformations as well as large rigid body motion. The load cases can be simulated by crash analysis tools such as LS-Dyna or multi-body dynamics analysis tools like Ansys Motion. The crash analysis has a better representation of structural compliances including large deformation with large rigid body motion. However, it requires a well-defined FE model and suspension multi-body models in detail. Furthermore, it takes a long time to get a result. On the other hand, the multi-body dynamics approach is very quick to get a result, while it has a limitation of representing structural compliance. The limitation is true in representing structural non-linearity such as large deformation associated with plastic yielding. In this study, a curb impact simulation was performed using the multi-body dynamic approach with nonlinear structural analysis capabilities included in Ansys Motion. The tool demonstrated the simulation was completed faster than other MBD tools due to recycling the system Jacobian matrix when structural deformation was not significant enough. The results were compared with structural analysis and correlated reasonably well. This approach proposed a new way to simulate customer abuse load cases, where only a part of vehicle system get significantly damaged such as Curb Impact and Pothole simulations.