철도차량 대차틀 피로균열 평가법 연구

In this study, fatigue crack growth rate of a cracked railway bogie frame under variable amplitude loading is predicted by applying linear elastic fracture mechanics. For this purpose, we find the critical points by reference surveying on cracked railway bogie frames. And we make an effective load history by synthesizing the dynamic load measured from the critical points of railway bogie frame during commercial line operation and the static load calculated from structural analysis. Crack growth analyses are performed at the 3 critical points under the commercial operation loading condition by assuming an initial crack size as 40 ㎜. and the results are compared with the experimental results from Japanese railway bogie frame crack growth case. From the analysis results, we find that around 500,000 ㎞ operating distance is necessary to bring crack growth from the initial crack to unstable crack. And it takes around 3.8 normal operating years. We conclude that it is enough time to detect the crack between normal maintenance period.