Design of the occupant protection system for frontal impact using the axiomatic approach

The functional requirements (FRs) and design equation of a flexible system change in a continuous manner with respect to a variable such as time. An event-driven flexible system is defined as a subcategory of the flexible system in that it changes in a discrete space. A design scenario is developed for the event-driven systems. The design equation for each event should be defined by using the axiomatic approach and the design equations are assembled to form a full design equation. The design equation for each event can be established by sensitivity analysis. In conceptual design, the design order is determined on the basis of the full design equation. Design parameters (DPs) are found to satisfy FRs in sequence. A DP may consist of multiple design variables. In a detailed design, the design variables are determined. The occupant protection system is an event-driven flexible system because the design matrix and its elements change according to the impact speed. The involved devices are designed on the basis of the developed method. FRs at different impact speeds and corresponding DPs are defined. In a detailed design, the full factorial design of experiments is employed for the design variables of the DPs to reduce the injury levels of the occupant. Computer simulation is utilized for evaluation of the injuries. The results are discussed.