Accelerated Fatigue Life Test of Domestic Midi Bus's Front Suspension Springs 2007-01-3646

In this paper, first of all, after load distribution of the front and rear axles of domestic midi bus have been measured, force on the parabolic springs of the front axle was calculated. Level of the good, middle and bad roads of Adana city in south of Turkey were determined and strain and displacement data have been recorded from connected strain-gage and LVDT sensors on the front axle parabolic springs of the midi bus. Test mechanism of the front axle suspension system connected chassis like midi bus was assembled in the laboratory. Recorded road roughness displacement, strain, and brake force strain data of the parabolic spring were processed by LMS Tecware, n-code ICE-flow 4.0 and special written computer program for this accelerated life cycle project. In addition to this, rainflow analysis, cumulative damage values, appending brake signals data in these different roads and every road damages have been calculated. Damages of different road signals have been arranged according to their bigness. So, eight big different damage road signals were selected for driven matrix. In the laboratory, same signals have been established by damages of real road signals and driven on hydraulic shaker. Accelerated life test signals and drive scenario have been constituted. Real simulation of 200 hours accelerated damage signal has been driven on the front axle suspension of the midi bus. As a result of this study, experimental results have been compared to real road drives.

A suitable front suspension parabolic spring of a domestic prototype midi bus has been determined. Accelerated fatigue simulation test that we constituted in our laboratory can be used for this kind of fatigue analysis of vehicle and its components. Therefore, time and money consuming will be reduced.