The Finite Element Analysis About The Effect Of Stress Concentration Of Welding Joints On The Fatigue Behavior

With the development of economy, the high speed has become one of the importantsymbols for modern transportation and the high speed railway has a extensive attention ofmany countries in the world,due to its many advantages, such as big traffic volume, lightpollution, low energy consumption.With the opening of the beijing-tianjin, WuGuangXian,our country also has gotten into a high speed railway construction stage, and this also has putforward higher requirement for property of high-speed locomotive vehicles. As the key oftrain parts, the bogie of the locomotive, its strength, fatigue performance cannot be neglected.In this paper welding, the basic link form of bogie, was researched, a large number of testsand research for the fatigue performance of welded joint were done. The paper mainlyanalysed the main factors of fatigue performance for the commonly used welding joint forms(butt joint, cross-shaped joint), weld geometric parameters (stress concentration coefficient).The research content and achievement are obtained as following:1.Because effect factors on fatigue property of welded components not only includes thebasic factors, the stress concentration, shape and size and surface state, etc. but also includesinfluence factors such as welding defects, residual stress due to the particularity of weldingtechnology. In order to research the effect of stress concentration of welded joints on thefatigue performance, this article firstly carried out the post-weld heat treatment (PWHT) torelieve welding residual stress, then did the corresponding fatigue tests.2.It introduced many different methods which are used to analyse the fatigueperformance of welded joints and theirs adaptation detailedly. It set up the model of welds andgot the stress concentration coefficient by means of finite element analysis (ABAQUS), thencalculated theirs theoretical fatigue life with different methods (traditional local stress-strainapproach, all kinds of modified methods) and compared.3.The paper used professional Fatigue software MSC. Fatigue to analyse fatigue life ofwelded joints by means of the modified local stress-strain approach which adapts to highcycle fatigue and compared them with test data to illustrate the reasonability and feasibility offinite element method. Finally the paper analysed the effect of geometric parameters (buttjoint, cross-shaped joint) on stress concentration coefficient and fatigue life systematicallyand got the relationship between stress concentration coefficient and fatigue life. Thisprovided the theory basis for getting the best shape of welds and improving fatigue property.