Study on establishment of standardized load spectrum on bogie frames of high-speed trains

Establishing structural load spectrum under actual operating conditions is a major problem in structural fatigue life analysis. This study introduces the load measuring method for the bogie frame structure. The load-measuring frame based on quasi-static can measure different load systems synchronously. The t-test method is employed to evaluate the least test time of deducing the parent distribution. In order to fit the load spectrum distribution accurately, the kernel density estimation method is employed which is based on the sample characteristics. The expansion factor method is used to deduce the maximum load. The formula of standardized load spectrum derives from the deduced maximum load, the linear factor between operating condition length and cumulative frequency and the parent distribution of each load system. The damage consistency criterion is performed by solving the objective function with constraint conditions. The calibrated damage provides a suitable representation of the real damage under actual operating conditions. By processing and analyzing the load spectrum and stress spectrum data of the measured lines, it is verified that the standardized load spectrum established in this paper is superior to the European specification and the Japanese specification in evaluating the fatigue reliability of the structure.

Strength Evaluation of a Bogie Frame by Different Methods

Some crucial loads that current strength design specifications have not taken into ac-count are also considered when assessing the strength of a bogie frame.Calculation methods of these loads come from load analysis.Finite element simulation and fa-tigue test rig have been used to assess static strength and fatigue strength of a bogie frame.In addition to the two methods,actual running test is also used to assess bogie frame fatigue strength.In finite element simulation method,endurance limit and modified Goodman fatigue limit diagram are two important tools to judge whether fatigue strength of a bogie frame meets requirement.In actual running test method,Miner linear cumulative damage rule is used to assess bogie frame fatigue strength.Endurance limit and modified Goodman fatigue limit diagram are two effective tools to judge fatigue strength of the frame.For the measured dynamic stress data,Miner linear cumulative damage rule seems to be very effective when judging fatigue strength of the frame.All the above methods have proved that static and fatigue strength of the tested bogie frame meets requirement.