一种双向曲率板成型应变分布的力学计算方法

在双向曲率板线加热成型及滚压成型的工艺设计研究中,一项十分重要的工作就是依据所需目标形状计算应变分布并以此确定加工路径和工艺参数,因此应变分布计算的精度直接影响到加工路径和工艺参数的准确性.本文介绍了一种基于力学方法的应变分布计算方法,首先对平板施加节点位移场进行弹塑性计算,由于存在回弹现象,需对节点位移场进行反变形修正,本文将得到的形状与目标进行对比后,再利用两者偏差对位移场进行迭代修正,直到两者偏差满足精度要求,最后将得到的应变场以初应变的形式输入到平板模型上,用初应变法的结果对应变的计算方法进行验证,证明该方法的精度,为后续加工路径和工艺参数的准确确定提供基础.

Calculating strain field to forming a double-curved shape based on mechanic theory

The determination of process paths and parameters according to the strain field that required to forming a double-curved desired shape is an important work during the process design of line-heating and rolling forming in thepro-cess design of line heating and rolling forming. Therefore, the precision of Calculated strain field will affect the accuracy of process paths and parameters. This paper presents a method to calculate the strain filed required to develop a desired shape to a planar shape depend on mechanic theory. Firstly, nodal displacements is applied to the flat plate via elastic-plastic finite element analysis. Owing to the spring back, the shape calculated by elastic-plastic finite element analysis is different between the required shape, then the deviation between calculated shape and required shape is calculated, and reverse deformation is added to nodal displacements, this process continues until the deviation can meet the requirement of precision to terminate the loop. Finally, the obtained strain field is applied to flat model as initial strain to verify the accuracy of this method, and results shows that it has very high calculation precision, this method provide the foundation of the determination of process paths and parameters.