| In recent years,high-strength steel has been successfully applied in many construction projects by its remarkable advantages in structural mechanical properties,usage function and economic benefits.Compared with ordinary steel,high strength steel has undergone changed greatly in terms of chemical composition and mechanical properties,so that the residual stress distribution model of ordinary steel is no longer applicable to high-strength steel.The Standard for design of steel structure(GB50017-2017)has included high-strength steel with a yield strength of 460 MPa,and directly followed the original design calculation method of ordinary steel components,which was found to be inappropriate in the subsequent design and research.Therefore,for the 690 MPa high-strength steel member with higher yield strength,the overall stability performance study including the residual stress distribution study is not yet comprehensive and needs further exploration.This paper uses ANSYS software to numerically simulate the size and distribution of longitudinal residual stresses in a variety of welded sections of Q690 high-strength steel.After gathering and coordinating the necessary data,it talks about the effect of plate width to thickness ratio and plate thickness on longitudinal residual stress and recommends a model for the allocation of longitudinal residual stress for a wide range of welded sections made of Q690 high-strength steel as a guide for further experimental studies on residual stress and numerical analyses of the security and stability of steel compression bars.The relevant research content and results are as follows:(1)Establish finite element models for calculating residual stresses of various welded sections.With the ANSYS to create a three-dimensional moving heat source finite element mathematical model of the soldering temperature distribution and stress distribution,through the thermal-structural coupling analysis function and "life and death unit model" to imitate the soldering course,to obtain the remaining stress size and distribution of the welded section.After contrasted the laboratory results of relevant scholars to checkout the precision of the finite element model.If the difference between the two results is very small,it indicates that the established finite element model of various section forms is accurate.(2)The numerical simulation results of residual stress distribution in welded sections of various cross-sectional shapes and sizes were obtained.Establish 6 groups of T-section member models,5 groups of H-section member models and 5 groups of box-section member models with different cross-section sizes respectively,and through finite element simulation analysis to obtain the size and distribution of longitudinal residual stress in the welded sections.The results show that the tensile stress is at the weld of both plates the residual compressive stress is at the end of flange and at the center of the web.(3)This paper proposes a residual stress distribution model for the welded section of Q690 high-strength steel.By integrating the numerical simulation results of residual stress of various sections,and analyzing the impress of relevant parameters on the longitudinal residual stress distribution.The results show with an increase or decrease in parameters leads to a significant increase or decrease in the residual compressive stress,but it is irrelevant to the tensile stress;the residual stresses in the flange and web are autocephaly self-balancing.Based on the parameter analysis,this post put forwards the residual stress distribution models go for the welded T-shaped,H-shaped and box-shaped sections of Q690high-strength steel.In summary,this post is eager to afford theory sustain for the experimental study of residual stress distribution in the welded section of high-strength steel,provide data prop up for the subsequent research on the stable bearing capacity of the pressure rod,and also give a vital reference for the modification of national standards. |
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