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This paper presents progressive techniques based on the previous SAE papers [1], [2] for vibration transmission analysis (VTA) on finite element (FE) model using Transfer Path Analysis (TPA). The techniques are: 1) a contribution calculation technique for structure with manifold and continuous transfer paths: 2) a visualization technique of the influence degree for efficient derivation of measures for response reduction. In VTA, influence degree of each DOF is calculated based on TPA. In order to understand characteristics of vibration transmission (VT) easily and visually by engineers, magnitude of influence degree is expressed by replacement to magnitude of displacement in the diagram of FE vibration shape. This visualization technique is applied to an automotive body structure. The proposed techniques are applied to automotive body structure consisting of members and panels. The members are such as pillars, cross members and side members, which are the main VT paths.

This paper describes a proposal of techniques on Transfer Path Analysis (TPA) to analyze transmission of vibration among the components in a complex structure. This proposal is evolved from the previous one [1] in the dimension which dominates the quality of the analysis in automotive body structure by TPA. The proper coordinate transformation was introduced to resolve the troublesome process on the application of the body structure in the previous proposal. The complications are caused by the treatment with a lot of transfer functions and transmitted forces at the conjunctions that are complexly assembled with many adjacent nodes. Dimension of the analytical region is expanded from two to three in this study. That is, from the cross section of interface of components to the structure itself where the vibration transmits between two components.

In this paper, the modeling technique of the dynamic characteristics of the monocoque-type tractor frame, and the reduction technique of the noise and vibration of the tractor by the design modification of the frame are proposed. First, the vibration characteristics on each part of the tractor, and the noise characteristic in the cabin are measured. Secondly, the full-structure of the frame is separated into the sub-structures of cases and joint parts, and each one is modeled. Then, the model accuracy is improved by using the model tuning method with the sensitivity analysis. Finally, the design change of the frame is carried out with the object of increasing stiffness while reducing weight. As the result of this modification, the cabin noise level can be effectively suppressed about 4 [dB].