Car Ride Safety and Comfort Analysis considering Low-frequency Vibration of Car Body

Abstract − In this paper, we found that modification of the local flexibility (or local stiffness) of the 4 parts onwhich shock absorbers are mounted in the vehicle body has some influence the level of ride safety and comfort.Multi-body dynamic analysis considering the flexibility of the vehicle body is performed using MSC/ADAMSand MSC/NASTRAN. More concretely speaking, natural frequencies and mode shapes computed by MSC/NAS-TRAN are used as input data for multi-body dynamic analysis in MSC/ADAMS. It is confirmed that the ridecomfort can be improved by appropriately changing the local stiffness of the vehicle body through several sim-ulations using MSC/ADAMS. Key words : ride safety, car body, flexibility, low-frequency vibration 1. Introduction In MBD analysis using a finite element of a vehiclebody, the input point inertance (IPI) and transfer pointinertance (TPI) analysis were carried out at locationswhere the vehicle body and the chassis are connected.The results of these analyses are used to develop animproved plan for the vibration transfer reduction andfor performing the verification analysis. FEM model,which is the same as an actual automotive and com-posed of a vehicle body, used Body In White (B.I.W.)and Trimmed model, and the model was compared withthe test results obtained through the modal analysis. In this research, we performed the modal analysis byperforming a simulation on the effects on the vehicleride safety and comfort about the local stiffness of thevehicle body. A study on the stiffness definition methodand the design modification for vehicle ride safety andcomfort evaluation were performed on the vehiclemounting point through the test.