Measurement And Analysis On Residual Stress In Welded I-shaped Cross-sectional Member

The new domestic series of high-performance steel GJ is the quality of upgrading and transforming steel for construction, which has a better overall performance than low-alloy high-strength structural steel used generally in present. Now it has been used in several construction projects, such as The Main Stadium for Olympic Games, the new airport in the national capital, CCTV new building.But the related design criteria hasn't been consummated,and the tests of members also need to be carried out.The residual stress of three types of welded I-shaped cross sectional members, 400x400x16x25, 500x500x25x35, 600x600x35x50 are tested, using blind-hole method.The material is Q345GJ structure steel which is manufactured by Wuyang steel company.The selected thickness of the plate has coverd the relevant thickness groups of Q345GJ structure steel.In the tests,the measure point is arranged along the outline of the I-shaped cross section.The space between two holes,which is closer in the region close to weld metal area and farther in the region far away from the weld metal area,is about 20~60mm.In the direction of the length,there are three paths of such annular arrangement of measure points.In the analysis,the general finite element software ANSYS is used to simulate the process of welding and three-dimensional model of I-shaped cross section will be developed and simplified.During this procedure,it considers the thermal physical properties and mechanical properties as a function of temperature.The main idea is using heat generation rate to simulate the heat source.By using the technics of element birth and death of ANSYS and inputting the heat gradually,we can make the heat source move,and the temperature field at any time will be obtained.Then,the outcome of temperature field analysis will be applied on the finite element model as loads and the welding stress field will be obtained by using the method of indirect coupling.After the comparison and comprehensive analysis of the test results and finite element analysis results,we can obtain the distribution of residual stress of the I-shaped cross section which will be used in the subsequent research after simplify.