激光宽带加工数值模拟中的热源模型

针对宽带激光表面强化过程,建立了激光宽带热源理论模型.基于有限元软件SYSWELD进行了激光熔凝数值模拟,将模拟计算得到的光斑作用区形貌尺度、三维瞬态温度场分布和热循环曲线进行了对比与分析.42CrMo板材表面激光宽带熔凝的试验验证表明,宽带热源模型得到的热源光斑及"平底锅"状熔凝区截面与实际相符合,熔凝区截面尺寸和试验结果一致,可以获得沿激光扫描方向合理的瞬态熔池分布,试验测定的热循环曲线与模拟值逼近.激光光斑辐照作用使得工件表面经历了一个急剧加热、快速冷却的过程,同已有的其它热源模型相比较,使用宽带热源模型计算得到结果更符合实际,可以准确地模拟激光宽带加工过程.

Heat source model in numerical simulation of laser wide-band processing

New wide-band volumetric heat source model fitting for the simulation of laser wide-band surface hardening processes was created. Based on finite element software-SYSWELD, dimensions of the laser radiative areas, the 3D transient temperature fields and the thermal cycles were simulated and analysed. The experiments on 42CrMo steel plate show that the simulated laser beam and the cross section with the pan shape of the laser remelting area coincide well with reality, and the reasonable transient melting areas distribution can be acquired along the laser scanning direction. Furthermore, the dimensions of laser remelting areas and the thermal cycle are in accordance with the experimental results. The surface of the workpiece undergoes a rapidily heating and fast cooling process with the radiative action of the laser beam. Compared with other heat source models, the wide-band heat source model can be suitably and accurately used for simulating and forcasting the laser wide-band processing.