Optimisation study of occupant restraint system concerning variations in occupant size and crash severity in frontal collisions

Restraint system parameter configurations encouraged by the current legislative or consumer crash tests cannot provide tailored protection to occupants with different statures under various crash severities. The restraint system parameters should be adapted to different circumstances. In this study, a restraint system optimisation framework was built to explore optimal configurations for five different sizes of occupants in two crash severities. Seat position was treated as a variable in the design space. The optimisation results showed that optimal seat positions had clear patterns for the two crash severities. In high crash severity, dummies tended to sit closer to the knee bolster to achieve better contacts of airbag and knee bolster. In low crash severity, optimal seat positions were farther from knee bolster. With aggressively tuned pretensioner and stature dependent load limiting values, the dummies were efficiently restrained by the seat belt. Tailored protections to the ten cases were achieved after the optimisation, compared to the fixed parameter restraint system.