DOI: 10.3724/SP.J.1249.2014.03233
为研究变压边力对差厚拼焊板成形性能的影响,以差厚拼焊圆筒形件为例,设计2种随位置、行程不同的变压边力方案,得到了差厚激光拼焊圆筒形件的成形极限深度、焊缝移动量、破裂危险点处应变路径及焊缝两侧应变分布的变化情况. 研究表明,薄、厚侧压边力的大小和分布对破裂危险点应变路径和安全裕度的影响很大,合理的变压边力分布可以调节焊缝两侧材料变形的均匀性,提高成形极限深度; 通过变压边力技术可以控制薄侧破裂危险点的应变路径由拉压应变状态向双向拉伸应变状态过渡,从而调节破裂失效的位置,有效提高差厚激光拼焊圆筒件的冲压成形性能.
To study the influence of variable blank holder forces on the formability of tailor-welded blank(TWB), cylinder-shaped parts with different thicknesses were used, and two kinds of variable blank holder force(VBHF)control schemes were designed. The forming limit depth, weld-line movement, strain path variations near the fracture zone and strain distribution changes across the weld-line were obtained. The results show that there is no inevitable connection between the forming limit depth and the amount of weld-line movement; the strain path of fracture zone near the weld-line is close to the plane strain state, while the strain path of the punch fillet is a segmented strain state which changes from a tension and compression state to a biaxial stretching state; with the increase of BHF on the thinner/thicker side, the strain concentration of thinner side will avoid the generation of rupture defects eventually.
