FEM approach for exterior moldings insertion/retention using LS-Dyna

The scope of the study was to understand the mechanical behavior of a retainer design - used to attach an exterior part on the body structure - during insertion and retention events and it was performed with the extensive use of finite elements tools, more specifically, LS-Dyna, a powerful FE tool able to run both explicit and implicit structural analyses commonly used in automotive developments to simulate dynamic events, such as high speed impacts. Several FE models were used to define best methodology in terms of modeling technic and contact representation. Additionally, based on physical tests, it was able to achieve a good virtual representation of the retainer forces and visualize each step of these events. These data were used to identify what dimensional parameters of the retainer were more important to “tune” the part performance. As conclusion, a new design was proposed able to reduce the insertion force about 43% with no decrease in the retention force.