鉄道用車輪の残留応力評価

概要

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Neutron stress measurement method is useful for determining, in a non-destructive inspection, the internal stress of engineering parts. However, there is a limitation such as the measurement is difficult if the path length of neutrons in the material exceeds 40〜50mm. As Webster et al. have stated adopted, cutting a sample is unavoidable in order to decrease attenuation in neutron intensity. The problem is, however, how the stress release should be considered. In this analysis, the finite element method (FEM) was applied to estimate the initial stress state using stresses released after cutting a sample obtained by the neutron method. Railway wheels were studied in this experiment. In the early 1990s, on several railroads in the northeast of the U.S.A. the wheels of the commuter trains experienced extensive cracking. Residual hoop stresses play an important role in the mechanism of fatigue damage. This paper will discuss residual stress in manufactured wheels. The results of FEM analysis were used to evaluate the residual stress. The validity of the results of the FEM analysis was evaluated by X-ray and neutron diffractions.
2010-03-25