Study On Residual Stress Of Welded H-Shaped Section Of Q690 Steel And Its Effect On Overall Stability Of Axial Compression Member

At present,with the continuous innovation of the new concept of architectural design,architectural styles have become colorful and diverse.Especially since the 21 st century,there are more and more steel structure buildings in our life.Therefore,higher requirements and standards are put forward for the properties of steel.With the rapid development of metallurgical technology and scientific materials,high strength steel has met the urgent needs of people in steel structure buildings.However,compared with Japan,the United States and other European and American countries,China’s research on high strength steel still lags behind them.The lack of research on high strength steel has seriously affected its popularization and promotion.In the research of high strength steel,the study of residual stress is an indispensable link.A large number of research results show that the existence of residual stress will not only reduce the stiffness of the member,but also reduce the stability of the structure bearing capacity.At present,there are few researches on residual stress distribution model of high strength steel,but the residual stress distribution model of ordinary steel is not suitable for high strength steel.In 2018,the new steel structure design standard(GB50017-2017)has been implemented.However,in the new version of the code,the residual stress of Q690 steel is not fully studied,so it needs to be studied.The main contents of this paper are as follows:(1)Measure the residual stress of 6 domestic Q690 high-strength steel welded Hshaped cross-section specimens by the cutting method,and use the straightening measurement method to make corrections.According to the residual stress value obtained from the experiment,the corresponding residual stress distribution model is proposed.Summarize several common residual stress distribution models,and compare them with the residual stress models proposed by myself.(2)The relationship between the steel residual stress level and the section size was explored through grouping comparison of 6 specimens.(3)The finite element calculation software ABAQUS is used to establish the calculation model of Q690 steel welded H-section axial compression member’s overall instability around the weak axis.The influence of residual stress and different residual stress distribution models on the ultimate bearing capacity of the axial compression column was further investigated.The ultimate bearing capacity of a large number of axial compression columns is simulated,and the simulation results are compared with the values of Chinese,European and American codes respectively,and the design suggestions for such axial compression specimens are given when they are unstable around the weak axis.given.