Static Strength Analysis And Structure Optimization By FEM In Vehicle Seat

Nowadays, more and more families in China have their own cars. Consequently, the comfort and safety of cars are becoming a hotspot, which are considered as one of the most important things, when someone buys a car. Being the closest part to people, seat and its comfort and safety have been paid more attention by the car drivers and the manufactures.In order to validate the reliability of simulation results, some tests were carried out. In the test, strain gauges were used to measure the detailed strain of some points on the seat frame. After data processing, the stresses of the points were gotten.A finite element model of seat frame was built in Hypermesh, which consisted of two kinds of section, shell section and beam section. There were 84391 nodes and 82679 elements in this model. Considering the loads distribution, the cover, seat cushion and some springs were ignored in the model. The seat frame was assembled by three kinds of connection, welding, bolting and riveting. In order to make the simulation easier, all the connections were defined as rigid connection in the model.Based on requirements in our national regulation, simulations were carried out using NASTRAN. Comparison with the test results hand shown predicted seat performance to have a high degree of accuracy with actual test data and the method used in building the FE model was reasonable. The average deviation of stress between the simulation and test was under 15%. Simultaneously, discussions about the cause of the differences between the test and simulation were presented in this paper in order to modify the model.In the pillow deflection test, a head model and a back model were required to be used to add the force. But it was too complicated for simulation. So the way of adding loads was simplified in the model and was validated by the tests.Although the seat has been changed partly for several times and can still satisfy the requirements in the regulations, it seems out of date compared with modern seat design. Therefore, this paper presented one improvement project on the seat structure.