Research On Fatigue Strength Of Metro Vehicle Power Bogie Frame Under Spectrum Load

At present,railway transportation is the most crucial industry that the government focuses while the theme of the industry has turned to be "high-speed and heavy-haul ".In this case,it requires a higher level of fatigue reliability of railway locomotive and car's bearing structure especially the frame of the bogie.Because the frames of the locomotive and car are welded and predicting the fatigue life of welded structure is complex and interdisciplinary,predicting the fatigue life of bogie frame has become to be the most hottest topic.This paper firstly summarizes the study situation and development tendency of fatigue strength on welded bogie frame.Then,it's obvious to draw this conclusion:adopting simulative operation load and dynamic test load provided by the structure strength tests standards such as UIC and TB as the fatigue design load of the bogie frame is scientific and reasonable in frame's initial design.So,the paper firstly uses the simulative operation load provided by TB/T2368-2005《Motive power units-Bogies and running gear-Bogie frame structure strength tests》(here in after TB/T2368-2005) to evaluate the fatigue strength of the main bogie frame based on infinite design life ideal.Then,the dynamic test load of TB/T2368-2005 is loaded to the welded bogie frame.The fatigue life of one whole welding line of the curb girder and two rims of break plain members of the frame is predicted referring to the newest BS EN1993-1-9:2005《Eurocode 3:Design of steel structures-Part 1-9: Fatigue》(here in after Eurocode 3) based on nominal stress.At last,the accumulated damage of the three above areas is drawn according to the lengthways distance between the node's X coordinate and the lengthways center of the curb girder.The bogie frame can be modified based on the results of fatigue strength evaluation.Areas where accumulated damage is high can also be obtained.The craftsmanship quality at these areas should be under strict control.The bogie frame should be redesigned if the damage is too high.There are two fatigue strength evaluation methods in this paper,the former is fatigue limit method based on infinite design ideal and the later is accumulated damage method based on finite design ideal.The paper has made some positive research progress in welded bogie frame's fatigue evaluation by combining the two methods well in its early design.