Convergence Study On Explicit Finite Element for Crashworthiness Analysis

To have better confidence on CAE prediction of crashworthiness analysis, the process of verification and validation for the explicit finite element method is essential. Selected examples are presented to study the convergence behavior and the quality of the explicit finite element method for transient dynamics.

For the axial vibration of a rod, the computed displacement and velocity, and the frequencies calculated by using Fast Fourier Transform achieve the optimal convergence rates when mesh is refined. For a clamped rectangular plate subjected to lateral load, the elastic deflection and rotation calculated by using Reissner-Mindlin plate element, achieve the optimal convergence rates within a range of thickness. For the motion excited by initial velocity, when the thickness is reduced however, the deterioration in convergence of velocity related terms is observed. For the high speed axial impact of structural components, with large plastic deformation, the convergence rate of some items below optimal value is observed, particularly when heavy contact occurs. With reduced thickness, deteriorated convergence is observed.