激光热应力板料成形角变形分析

Analysis on Bending Angle of Laser Forming

为了精确预测板料直线扫描时的角变形,本文采用简化约束模型分析了板料的变形历史和应变产生机制,在加热区域内将激光热应力变形过程分为3种不同的情况:(1)板料上下表面仅产生弹性变形;(2)板料上表面产生弹性变形和塑性变形,下表面仅产生弹性变形;(3)板料上下表面均产生弹性变形和塑性变形。通过对热变形第一种情况进行分析,提出了最小移动能量密度的概念,并推导出了板料产生热变形所需要的最小移动能量;针对热变形第二和第三种情况分别建立角变形解析模型,试验结果验证了该模型具有较高的精度。

To achieve the precise prediction of the bending angle in the laser forming process, the deformation of the sheet metal is analyzed based on simplified models. The deformation of the heating zone is divided into three cases： （1） only generating elastic deformation in the top and the bottom surfaces;（2） generating elastic and plastic deformations in the top surface and only elastic deformation in the bottom surface;（3） generating elastic and plastic deformations in the top and the bottom surfaces. In connection with the first case, the moving energy density is defined and the minimal moving energy density beyond which plastic distortion occurs is obtained. Analytical models of the bending angle are developed based on the analysis of both the second and the third cases, which consider the dimensions of the plate,material property and laser scanning parameters. The comparison of the calculations using the proposed analytical model with experimental results shows a good correlation.