Development and Validation of a Motocross Helmet Shell Finite Element Model

The purpose of this study is to develop a finite element (FE) model of an existing DOT-approved, Omni-Directional Suspension (ODS) motocross helmet shell, as a means of optimizing helmet design to mitigate head injury risk. To assess the structural behavior of the composite shell (constructed of various fibers embedded in an epoxy resin), a physical, quasi-static 3-point bend test is conducted on various shell samples. In conjunction with the physical test, a simulated 3-point bend test is conducted in the multi-physics simulation software, LS-DYNA. The helmet shell is represented in LS-DYNA with *MAT_58, a continuum damage material used to model woven fabrics and composite materials. As a means of validating the FE model, comparative analysis is conducted between the simulation and experimental 3-point bend test results to confirm that *MAT_58 is capable of predicting the helmet shell’s structural behavior. Development of a valid motocross helmet shell FE model will contribute to future development of the full OSD helmet model. Once constructed, the full motocross helmet FE model can then be fitted over LS-DYNA’s existing Hybrid III 50th Percentile Male Anthropomorphic Test Device (ATD) FE model to simulate translational and rotational impact and in turn, assess head injury risk.