船用中厚钢板激光弯曲成形过程数值模拟

【作者】 裴继斌；

【导师】 张立文；

【作者基本信息】 大连理工大学 ， 材料学， 2002， 硕士

【摘要】 板材激光弯曲成形技术是利用激光束扫描金属板材时产生的热应力使板材成形的新工艺，在汽车、造船和航空等领域具有广阔的应用前景。激光束扫描板材时，在照射区域和邻近区域产生强烈的温度梯度，使材料产生非均匀的热应力分布，当热应力超过材料的屈服点时，材料发生塑性变形。 本文使用有限元软件MSC.Marc对板材激光弯曲成形过程进行数值模拟。综合考虑材料的热物性和力学性能随温度的变化等因素，建立了三维热力耦合模型分析船用中厚钢板激光弯曲成形过程，计算成形过程的温度和应力应变，并预测钢板最后的弯曲角度。 为了验证数值模拟结果，对船用中厚钢板激光弯曲成形过程进行了实验研究。分别选用不同厚度、不同扫描速度和不同激光功率对金属板材激光弯曲成形进行参数研究，对温度和弯曲角度的变化进行实时测量。弯曲角度受材料力学性能、热物性以及工艺参数等因素的影响，随激光束扫描次数的增加而增大，是激光功率和扫描速度的函数。模拟结果与实验结果符合较好，从而验证了模型的适用性。更多还原

【Abstract】 Laser forming is a promising technology in manufacturing, such as in the automobile, shipbuilding, and aerospace industries. The process utilizes the thermal stress induced by laser irradiation to form sheet metal into different shapes. The local nature of laser irradiation yields high temperature gradients between the irradiated surface and the neighboring material. The temperature distribution makes the material to expand non-uniformly, thus leading to non-uniform thermal stresses. When the thermal stresses exceed the yield point of the material, the material deforms plastically.The laser forming process has been simulated numerically. For the analysis, the finite element code ’MSC.Marc’ is used. A 3-D FEM simulation has been carried out, which includes a coupled thermal-structural analysis accounting for the temperature dependency of the thermal and mechanical properties of the materials. The proposed model is capable of calculating the time-dependent temperatures, stresses and strains during the laser forming process. It can also predict the final bending angle of shipbuilding plates.An experiment was carried out to valid the numerical simulation. The sheet metal of different thickness had been performed for different scanning speeds and laser powers. The measurement of real-time temperature and bending angle was carried out. The bending angle is affected by the mechanical and thermal properties of the sheet metal material, the processing parameters, and the output of laser energy. The bending angle is increased with the number of laser beam scanning passes and is the function of the laser power and the laser beam scanning speed. The simulation results are in agreement with the experimental results.更多还原