MTFM的建立及其在铝合金筒体结构焊接变形预测中的应用

ESTABLISHMENT OF MOVING TEMPERATURE FUNCTION METHOD AND ITS APPLICATION ON WELDING DISTORTION PREDICTION OF CYLINDRICAL AND CONICAL ALUMINUM ALLOY STRUCTURES

应用以温度为控制变量且体现焊接温度场瞬时移动特性的高效计算方法——移动温度函数法(moving temperaturefunction method,MTFM),综合采用材料性能依赖于温度及温度历史的材料新模型,建立了4种几何尺寸铝合金简体结构的焊接过程三维有限元模型,预测了焊后母线下凹变形.同时,应用传统顺序耦合计算方法建立了有限元模型以对比计算效率与精度,并进行了实验验证.与传统顺序耦合计算方法相比,MTFM耗时均缩短60%以上,大幅提高了计算效率;所预测的铝合金简体结构焊后下凹变形量与传统顺序耦合计算方法模拟结果以及实际测量结果均吻合较好,计算误差小于10%.本文所应用的高效焊接数值模拟计算方法适用于不同几何尺寸铝合金简体结构,一定程度上说明了MTFM对不同结构和尺寸的焊接结构焊后变形预测的适用性.

Long computational time for thermo-mechanical simulation of welding distortion and residual stresses hinders the application of this technique in large welded structure.It is of urgent need to develop a high efficiency numerical simulation strategy for welding process.The traveling temperature function method,in which the quasi-steady state character of welding process was exploited,was applied in the present study to improve the efficiency of welding simulation.Also the temperature and temperature history dependent material property models were established and applied.The finite elements analysis（FEA） models of 4 types of cylindrical and conical aluminum alloy structures,with different geometric shapes and dimensions,were built to analyze.Traditional moving heat source models were also established for these 4 structures to compare with the traveling temperature function method.The welding induced distortions were predicted by both methods for all the structures.The time cost of the traveling temperature function method is less than 40%of that of the traditional moving heat source method.While the computed distortion trends and values of two simulation methods were consistent.Finally the validation experiments were carried out and the distortions were measured.The measured distortions were compared with the numerical simulation results of two methods.The comparison show goods agreement.The errors between computed results from the two methods and the experimental results are no more than 10%for all types of structures. This indicates that the numerical simulation models are not only highly efficient,but also suitable for different types of cylindrical and conical aluminum alloy structures.So the traveling temperature function method is a high efficiency numerical simulation method with abroad applicability.This is a beneficial attempt and a novel idea to driving numerical simulation method in application of the large welded structures.