【摘要】 为在矫直过程中对H型钢的残余应力实施有效地主动控制,对H型钢矫直过程中残余应力演变过程的力学机制进行研究。首先运用弹塑性基本理论对具有初始残余应力的H型钢截面弹塑性反弯过程进行解析分析,论证初始残余应力对截面弹塑性反弯过程的影响方式,证明初始残余应力导致截面弯曲中性轴位移的非对称弯曲状态。在此基础上,利用差分方法建立H型钢矫直过程多次连续弹塑性反弯的数值解法,进而详细研究H型钢矫直过程中残余应力的演变机制。结果表明:截面翼缘与腹板整体拉压应力水平的消减主要依赖矫直前期的非对称弹塑性弯曲过程,而矫直后期的对称弯曲过程则进一步改善H型钢翼缘的残余应力状态;矫直过程前期与后期不同的弹塑性弯曲性质造成了其在矫直过程中对于残余应力演变的不同影响作用。更多还原

【Abstract】 In order to control the residual stress of H-beam during the straightening process effectively,the mechanical mechanism behind the evolution of residual stress was studied during the straightening process.The elastic-plastic bending process of H-beam section with initial residual stress was considered analytically based on the elastoplastic bending theory.The way that the initial residual stress affects the elastic-plastic bending process was demonstrated,and it is also proved that initial residual stress of the section leads to the asymmetric bending of the displacement of the section neutral axis.On the basis of the analysis,a difference method was established to describe the continuous bending process of H-beam during the straightening process.The evolution mechanisms of H-beam residual stress during the straightening process was studied.The results show that the asymmetric elastic-plastic bending process at the earlier stage of straightening process is the main reason for reducing the tension-compression stress state of the web and flange,while the symmetrical bending process in later stage of the straightening process further improves the residual stress state of the flange.The different elastoplastic bending properties during the early and later stage of the straightening process play different roles in the evolution of residual stresses during the straightening process.更多还原