不同激光热源模式下薄板弯曲特性数值模拟

利用非线性有限元分析软件,建立了纯铝薄板激光成形过程的三维弹塑性热力耦合有限元模型.选择等面积的圆形、方形、矩形1/4和矩形4/1光斑激光热源模式(矩形1/4和4/1表示激光光斑沿着光束扫描方向尺寸与垂直光束扫描方向尺寸的比例分别为1∶4和4∶1),对不同激光热源模式下的板材弯曲特性进行了数值模拟计算,并分析了各种热源模式作用下板材温度场、位移场和应力应变场的特点.结果表明,在扫描过程中,圆形光斑热源模式获得了最高的峰值温度和上下表面温度差;而矩形1/4激光热源模式获得了最大的高温区作用宽度.矩形1/4激光热源模式产生了最大的塑性区宽度及上下表面总塑性应变差,因此获得了最大的弯曲角,内部残余应力最低.

Numerical Simulation of Bending Properties for Sheet Metal with Different Laser Source Modes

The three-dimensional elastoplastic thermo-mechanical coupled finite element model of laser forming for pure aluminum plates is established with nonlinear finite element analysis software Msc.Marc. Circular, square, rectangular 1/4 ( the size ratio of laser spot along the laser scanning direction and its vertical direction is 1:4, same as below) and rectangular 4/1 laser spots with the same area are chosed as the heat sources. The bending properties of sheet metal with four different laser source modes are simulated, and the temperature field, displacement field, stress and strain field are analyzed. The results show that the circular laser spot acquires the highest temperature peak value and temperature differences between upper and lower surfaces, while the rectangular1/4 laser spot acquires the largest width of high temperature zone. The rectangular 1/4 laser spot which owns the widest plastic strain zone and highest total plastic strain differences between upper and lower surfaces obtains the highest bending angle,and also the lowest residual stress.