Modeling and Validation of Static and Dynamic Seat Cushion Characteristics

Automotive seat cushions contribute considerably to static and dynamic comfort of the drivers. Design of a cushion is highly challenging due to its highly nonlinear viscoelastic behavior that is dependent on the seated body mass, and magnitude and rate of the vibration excitation. In this study, a dynamic seat cushion model is developed in the LS DYNA platform to determine its static and dynamic properties. The material model *MAT_FU_CHANG_FOAM_DAMAGE_DECAY (083_1) was used, which showed capability to predict nonlinear dynamic cushion behavior under different preloads, and excitation frequencies and amplitudes. This material model, available in the LS DYNA library, permitted evaluations of the nonlinear rate-dependent viscoelastic behavior of the cushion. The effectiveness of the model in predicting static and dynamic responses is demonstrated by comparing the simulation results with the laboratory-measured data in terms of force-deflection characteristics. The comparisons revealed reasonably good agreements between the simulation and measured responses. Contact pressure distribution on the seat cushion was further obtained, which also showed good qualitative agreement with the reported measured data.