板料激光曲线弯曲成形温度场的数值研究

Numerical Study on the Influence of Temperature Field on Laser Bending of Sheet Metals

板料激光弯曲成形是一种利用激光成形构件的柔性成形技术。以矩形板激光单次扫描成形的过程为研究对象,通过对有限元分析软件ANSYS进行二次开发,建立了基于扫描路径的动热源模型,并系统研究了各技术参数下激光弯曲温度场的动态变化。分析发现:(1)曲线扫描准稳态过程的温度峰值要小于同工况下直线扫描情况,且持续时间短暂,温度峰值不断跳跃;(2)相同工艺参数下,随着扫描路径曲率的增大,温度峰值及加热区温度梯度均减小,当扫描路径曲率继续增大时,温度峰值及加热区温度梯度却随之增大;(3)提高激光功率,降低扫描速度以及在恒定线能量密度下增大扫描速度,均使板料温度梯度增大,而增大光斑直径,温度梯度减小。

Laser bending is a recently developed and highly flexible metal forming technique. In this paper, numer ical study on laser bending of sheet metals are carried out with ANSYS software. The moving model of laser beam based on scanning paths is built and the dynamic temperature fields under different process - parameters are analyzed. The results show that, the temperature peak value in the steady course is low and jumping continuously, and the course is transitory; the temperature peak value and grads increase with the increase of the curvature of scanning paths; as well as the temperature gradients increase with the increased laser power, decreased scanning velocity, or increased scanning velocity under constant line energy density, while the temperature gradients decrease by increasing the laser spot diameter.