高分子材料与金属激光微焊接实验与仿真分析

Finite element simulation and experimental study about laser micro-joining between biopolymer and metal

为了更好地理解高分子材料与金属材料的激光微焊接机理,利用软件ANSYS建立高斯热源模型,对生物高分子材料聚对苯二甲酸乙二酯(PET)与医用金属材料纯钛的激光微焊接温度场进行了动态模拟;利用红外热像仪测定焊接过程瞬态最高温度变化,用超景深数字显微镜测量实际焊接中焊缝宽度,其测量结果与仿真结果基本吻合;最后对温度场仿真结果进行了分析。结果表明,移动热源前方的等温线分布密集且温度梯度大,后方的等温线稀疏且温度梯度小;在垂直于焊缝中心不同位置的节点都存在着快速升温及相对缓慢的降温过程,同时,节点越靠近焊缝中心,温度变化越剧烈,所能达到的最高温度就越大。该结果证明了所建立的移动高斯面热源模型在激光微焊接PET/Ti温度场模拟中的适用性。

In order to understand the laser micro-joining mechanism better, based on the ANSYS, finite element simulation software, the Gaussian heat source model was adopted to simulate the dynamic temperature filed in the process of welding polyethylene terephthalate （PET） and biomedical Ti. The transition highest peak temperature variation during the process of welding was recorded with a thermal infrared imager and the actual welding seam width was measured with a digital microscope in super depth of field. The simulation results are conforming to the experimental results. Simulation result suggests that the isotherm is as an ellipse. Meanwhile, there is intensive isotherm and larger temperature gradient in the front of the spot center, on the contrary, sparser isotherm and smaller temperature gradient at the back of the spot center, which verifies the applicability of the model established by moving heat source during the laser welding based on PET/Ti sheets applying to the temperature field simulation.