| Currently, the railway has become an important means of transportation.In order to adapt to the development, we need to improve the speed of the train. During the train running, the structure is in a long-term effect of random stress with damage occured and gradually accumulated. When the damage reaches a certain level, it will lead to fatigue failure which is a serious threat to traffic safety. Stress spectrum with high degree of confidence is an important basis for study of fatigue damage. However, due to cost factors such as time or testing, stress-time cours is only a small portion of the data during the entire life. Use the limited samples on the overall distribution of statistical inference to obtain stress spectrum with a high degree of confidence which is an important basis for study the effect of changing the wheel-rail matching state to damage evolution.This paper take the train CRH5 EMU as a test target, using dynamic data logger of HBM’s EDAQ32 to collect data with a period of ten months between Beijing west station and Taiyuan station. The main analysis of this paper is as following.(1) Based on theory of rain-flow counting by using Mycode software with GPS signals, the one way stress spectrum of each point was obtained. Finally the stress spectrum samples of each point are between 250 to 450.(2) Distribution fitting and F or t hypothetical test of each one-way stress spectrum is proeessed to obtain three parameters of Weibull distribution, such as shape parameter, location parameter and scale parameter; Based on statistieal theory to organize the distribution of parameters and Conver theory to infer the maximum stress of the stress speetrum, the stress speetrum with 95% confidence level was obtained which is the basis for study the fatigue damage.(3) Based on theory of Miner linear cumulative damage, the damage of each point was determined and based on stress spectrum of each point which is received, the equivalent stress was determined. In the entire course of operations, the analysis with the effect of wheelset lathing to damage evolution was taked which will provide a basis for reasonable period of wheelset lathing.(4) According to the data fluctuation before and after the effect of wheelset lathing, the entire coures was divided into five operating ranges. In the 95% confidence level, Based on theory of independent samples t-test, the minimum number of samples was identified which is represented the entire samples in one range. Accordingly, the research results can shorten the testing cycle and save costs. Also it can make the test work of stress speetrum economically and scientifically. 51 pictures,31 tables,54 references. |
