Modal Analysis for the Monocoque-type Frame of Agricultural Tractor

Investigation of Modal Parameters Applying Numerical Analysis

Abstract

At the beginning of optimum design study of tractor frame, modal analysis including sensitivity analysis was carried out to derive some fundamental design data applicable for further synthesis of vibration problems. Two models designated as model-A and-B respectively were used and the set of design parameters consisted of the number of partition walls of the power transmission case, thickness of the differential housing and the frame thickness. In a model-A, the thickness of partition walls and frame showed to be highly sensitive to natural frequency. In a model-B, the sensitivity of specific design parameters were evaluated quantitatively. Based on the result of frequency response analysis, with the decrease of the frame thickness from 25mm to 15mm, the maximum amount of decrease in terms of the acceleration level toward vertical direction took approximately 15dB at the connection of tractor frame and seat base.