激光点热源作用下动态微变形的数值模拟与校验

采用MSC．Marc非线性有限元软件，对试件在激光点热源作用下动态微变形过程进行了数值模拟。通过激光反射放大系统测量了试件在激光点热源作用下的动态微变形过程。模拟值与实测值的结果表明：热应力和相变应力的共同作用使得试件产生微变形，最终试件的变形方向取决于热应变和相变共同作用的结果，朝向激光束或背向激光束。比较实验值和模拟值，发现变形的最大值相近，变形过程却略有不同。考虑到激光点热源作用下有限厚度的试件内，温度场分布出现的反常效应，即内部的温度大于边界温度，提出采用波动理论修正经典的热传导计算模型，可望有效地提高模拟过程的计算精度。结论为进一步研究薄板激光弯曲的变形机理及变形过程奠定了基础。

Simulation and Verification of the Dynamic Micro-Deformation under Laser Point Source

The dynamic micro-deformation of the specimen under laser point source is numerically simulated by MSC. Marc software and measured using laser beam reflex amplifier system. Experimental result and simulation result show that the common action of thermal stress and phase transformation stress makes the specimen deformation. The final deformation direction of the specimen depends on the result of the co-operation of the thermal strain and the phase transformation strain, backwards or towards the laser beam. Compared the experimental with the simulation result, the largest deformation is almost the same and the deformation process is a little different. Considering that there is a kind of un-convention temperature distribution in the limit thickness specimen under laser irradiation, the temperature of inner material is higher than that of the boundary. Wave theory is suggested to modify classical heat transfer model so that simulation precision is improved. The conclusion lays the foundation for further research on mechanism and the process of laser bending.