Restraint system optimization for belted and unbelted occupants in frontal crashes

Jingwen Hu (University of Michigan)

CHALLENGE - Although seatbelt interlocks are now allowed, Federal regulations still require vehicles to meet occupant performance requirements with unbelted test dummies. Removing the test requirements with unbelted
occupants might encourage the deployment of seatbelt interlocks and allow restraint optimization to focus on belted occupants. The objective of this study is to compare the performance of restraint systems optimized for belted only occupants with those optimized for both belted and unbelted occupants using computer simulations.











SOLUTION - In this study, two validated finite element (FE) vehicle/occupant models, including a mid-size sedan and a mid-size SUV were selected. Response surface models using simulation results under standardized crash conditions for both vehicles on both driver and right front passenger positions were developed using modeFrontier, and then restraint design optimizations with and without unbelted requirements were conducted for four occupant-vehicle conditions.

RESULTS - Results indicate that, compared to the optimal designs with unbelted requirements, optimal designs without unbelted requirements generated the same or lower total injury risks for belted occupants, but they also increased the total injury risks for unbelted occupants.