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The purpose of this paper is to evaluate and reduce the operator exposure to vibration and shock in cabin of excavator. A simple 3-DOF mass-spring-damper system, which consists of three 1-DOF sub-systems - engine and cabin mounting systems, and base frame- was assumed to model the complicated vibration transmission path. By investigating this simple model, the best constitution of characteristics of engine and cabin mounts and stiffness of frame was determined. Especially, the viscous hydraulic mount was applied to the cabin mounting system. New system was examined under various working conditions and compared with existing one. The most common method specified by ISO standard 2631 was used to evaluate and compare the effects of whole-body vibration between new and old systems. Results of examinations showed improvement of vibration, shock, and noise.

The 3D transient thermal elastoplastic finite element analysis for a butt joint GMAW has been performed. A plastic hardening recovery model has been introduced and examined to consider the solid-liquid and solid-solid phase changes. The effects of cut-off temperatures and plastic hardening models are also examined. The results of numerical analysis show good agreement with those of experiments in both temperature and residual stress fields. The present model shows remarkable improvement in computing time.