矫直过程截面复杂反弯的应力分布与反弯特性解析

为了深入研究和认识辊式矫直过程中截面的反弯特性,研究存在弹塑性弯曲历史的截而弯曲过程,采用工程弹塑性力学基本理论,建立合理的辊式矫直复杂弯曲力学模型.解析证明经历二次反弯的截面应力形式应当由两次弯曲参数构成的平面方能进行描述,二次反弯过程截面的弯矩(M)与曲率比(C)的关系实际为包含两次弯曲的2个弯曲参数的复杂函数.通过对经历二次反弯的截面应力分布与反弯特性的解析,证明辊式矫直过程中经历多次弹塑性弯曲的截面受变形历史的影响,其应力分布函数及M-C关系都不再是简单关系,而是包含全部弯曲历史参数的复杂函数形态.解析结果表明:辊式矫直过程中经历二次反弯的金属条材截面弹性极限弯矩值下降,弯曲所需弯矩减小,弯曲回弹比增大,工程应用时应对相关工艺参数进行相应调整.

Stress distribution and reverse bending behavior of section during roller leveling process

In order to study the bending behavior of the section during roller leveling process,the bending process of the section which contains the history of elastic-plastic bending process was investigated.With the basic theory of elastic-plastic mechanics,a reasonable mechanical model of complicated bending process of the section was built.With this model it is proved that the stress in the section coming from the second recurvate process must be described by the coordinate plane constituted by two bending parameters,and the M-C relation of the section coming from the second recurvate process is actually a complicated function which contains two bending parameters.By analyzing stress distribution and reverse bending behavior of the section coming from the second recurvate process,it is proved that the stress distribution and reverse bending behavior of the elastic-plastic bending section,affected by several times of deformation during roller leveling process,are no longer a simple one,but a complicated function which contains all the historical parameters of bending.Analytical results show that during the second recurvate process,there are decreased elastic limit bending moment,reduced bending moment and increased springback ratio.Therefore related parameters should be adjusted accordingly in terms of engineering application.