| As the most important part of motorcycle, frame affects the ride comfort and safetyof the complete vehicle. Fatigue damage is the main destruction form of frame. So it’simportant to test the fatigue life of motor frame in initial development. But the existingtest method standards are full of problems. In this paper, the road tests and indoorfatigue tests of the frame are done; the results are analyzed by using the theory offatigue damage. a new idea to correct the existing fatigue test methods is put forwardbased on the national standard GB/T4570–2008, and two kinds of correction methodand their modifier formula are proposed. The work of this paper is reference valuableand theoretical significant to form a unified, standardized fatigue test method andevaluation standard of motorcycle frame, and is practical valuable in improving designquality, reducing the designing time and cost.The force analysis of the frame is carried on firstly to determine three limitingcondition in use of the motorcycle, and FEM analyses of the frame is finished in threeworking conditions based on the finite element method with the whole frame underquasi-static state condition. Hence, the stress distribution of the frame is obtained andthe measuring points of frame test are determined.Road test and indoor fatigue test are carried out based on national standard andoccupation standard. And the results of tests are counted by simplified rain-flowcounting method. Then, the value of fatigue damage is calculated with linear cumulativefatigue damage theory.The fatigue damage of road test is amplified to the national standard road testmileage damage value which is equal to the damage of indoor fatigue test, based on thefatigue damage equivalent principle. So the fatigue test method and evaluation standardof occupation standard QC/T819–2009can be corrected. |
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