Co-simulation of a Dynamic Stiffness Test of a Seat Cushion Using Finite Element and Multibody Dynamic Models

Dynamic performance of suspension seats depends on characteristics of both the suspension and the seat cushion. The objective of this study is to develop a hybrid method based on the concept of co-simulation between multibody dynamic and finite element models. The methodology is illustrated via simulating a dynamic stiffness test of a seat cushion. The dynamic stiffness of a cushion was measured on an indenter test rig using broadband random input signals (0.5-25 Hz) of different magnitudes (0.25, 0.5 and 1.0 ms-2 r.m.s.) and preloads (400, 600 and 800 N). A finite element model of the seat cushion is built up in MARC and a multibody dynamic model of the test rig is established in ADAMS. During the co-simulation, the multibody model calculates and passes kinematics of the test rig to the finite element model of the cushion. Based on these kinematics the finite element model calculates the force and feeds back to the multibody dynamic model. The hybrid model is calibrated through correlation between measured and computed dynamic stiffness. It is expected that the developed methodology can be extended to modelling of suspension seats where multibody model of the suspension co-simulates with finite element model of the seat cushion.