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In this paper, resonance durability analysis is performed for the fatigue life assessment of suspension component considering the dynamic effect of vehicle system. In the resonance durability analysis, the frequency response data and the dynamic load data of frequency domain are used. The multi-body dynamic analysis, finite element analysis and fatigue life prediction method are applied for the resonance durability analysis. To obtain the dynamic load history, the computer simulations running over typical pothole and Belgian road are carried out respectively by utilizing multi-body dynamic vehicle model. The durability estimation for the rear suspension system of the small-sized passenger car is performed by using the resonance durability analysis technique, and the estimation result is compared with the quasi-static durability analysis result. The study shows that the fatigue life considering the resonance frequency of vehicle system can be effectively estimated in early design stage.

This paper discusses the flexible chassis effects on dynamic response of engine-mount systems using computer simulation techniques. Equations of motion for the engine-mount systems including flexible foundations are derived. The dynamic flexibility of the chassis is represented by modal information from finite element analysis or experimental modal tests. Solving the derived equations, natural frequencies and forced vibration response of an engine-mount system can be simulated accurately. It is shown that the flexibility of the engine-mount frame structure may have a significant impact on the idle shake vibration and mounting forces transmitted from the engine to the structure. The computational method developed is applied to an example engine-mount system and the results are compared to those of an associated experiment.

Low frequency vibration characteristics of a vehicle are mainly influenced by the stiffnesses of the beam type structures such as pillars and rockers, and by the stiffnesses of the joint structures, at which several beam structures are jointed together. In the early design stage of the car body structure a simple FE model has been used, in which joints are modeled as linear springs to represent the stiffnesses of the joint structures. In this paper a new modeling technique for the joint structure is presented using an equivalent beam, instead of using a spring. The modeling technique proposed is utilized to design optimal joint structures that meet the required vibration performance of the total vehicle structure.

This paper presents a new method for the 5mph vehicle's bumper section shape optimization. The Intermediate Response Surface Modeling (IRSM) technique is newly introduced to approximate the nonlinear force-deflection curves. This can avoid the excessive 3D nonlinear FEM analysis during the optimization process. Then, the accuracy of the IRSM models is examined by comparing their results with those of the 3D nonlinear FEM. Finally it is shown that the proposed approach is effective to design the 5mph vehicle bumper section.