冷弯方管纵向残余应力分布的数值分析

Numerical Analysis of Longitudinal Residual Stress Distribution in Coldformed Square Hollow Sections

摘要:

应用有限元数值技术,模拟了冷弯方管的辊弯成型与回弹过程中所产生的截面纵向残余应力分布,并分析了冷弯方管宽度、壁厚和钢材屈服强度等参数对其纵向残余应力分布的影响效应.研究表明冷弯方管纵向残余应力沿壁厚方向呈现非线性分布,外壁受拉、内壁受压,外壁与内壁在数值上基本相等;弯角部位和平板部分的纵向残余应力幅值分别达到冷弯方管钢材屈服强度的50%和45%;随着壁厚的增加,边长小的冷弯方管纵向残余应力有所提高,而边长大的冷弯方管这种趋势并不明显;随着边长的增大,冷弯方管纵向残余应力减小;随着冷弯方管屈服强度的变化,纵向残余应力与屈服强度的比值变化不大.

Abstract:

Finite element numerical technique is used in the paper to simulate the longitudinal residual stress (LRS) distirbution in a coldformed square hollow section (CFSHS) which is produced during its rollforming and springback process,and then to investigate the effects of CFSHS’s width,wall thickness and yield strength on the LRS ditribution.It is concluded that LRS along the CFSHS’s wall thickness presents a feature of a nonlinear distribution,tension at the outside surface but compression at the inside surface,and mostly the same amplitude at the both surface.The LRSs at the corner and at the flat side come to 50% and 45% of CFSHS’s yield strength respectively.The LRS for a smaller width increses,whereas the LRS for a larger width does not show such the trend,as the wall thickness increases.The LRS decreases,as the width increases.The ratio of LRS to yield strength does not change significantly,as the yield strength varies.