激光拼焊板焊缝仿真处理方式研究

目前常用的金属板料冲压成形软件,一般不考虑拼焊板焊缝性能的刚性连接处理方式,这在某些工况下会造成与实际成形结果的较大偏差。为兼顾效率与精度,通过对焊缝性能的分析,提出在仿真中使用壳单元,并对焊缝赋予特殊材料属性的焊缝处理方式。试验证明,此种方式在拼焊板两侧母材强度相当时,相对于传统刚性连接方式,与试验结果有高度的吻合性,体现出了良好的精度,具有工程应用价值。该研究在此处理方式的基础上仿真分析了同材、同厚拼焊板的成形过程,探讨了其成形能力相对于单一母材有较为明显下降的原因,认为,焊缝较低的塑性与延伸率,致使其在成形过程中应力高度集中、易于脆断,并影响周边母材的成形,从而制约了拼焊板整体变形潜力的发挥。

Investigation on the ways of simulation treatment for the welding joint of tailor welded blanks

The welded seam of the tailor welded blanks (TWB) is treated as rigid connection by using the commonly employed sheet forming software.So excessive deviation may exist between the experimental results and simulation results.Considering both efficiency and accuracy,based on the analysis of the performance of welded seam,the method using shell elements with performance of welded seam is applied in simulation.It is proved by experiments that when the base metals of both sides possess similar strength,this method has positive engineering value for more accurate simulation result can be achieved in comparing to the method of rigid connection.Based on this method,with base metals and thickness of both sides being the same,the bulging process of TWB is analyzed by simulation and the reason of inferior formability of it in comparing to single base metal is discussed.It is founded that the forming capacity of TWB is limited due to the inferior plasticity and extensibility of the welded seam which result in serious stress concentration and more probability to produce brittle failure.At the same time it also influence the formability of the base metal near the welded seam.