中文摘要：

焊缝两侧材料变形不均匀引起的焊缝移动和成形性能下降是拼焊板成形过程中需要解决的难题，变压边力技术可以增大成形工艺调整范围、提高冲压件成形质量。本文在拼焊板成形过程中加载随行程线性渐增变化的变压边力，并应用动力显式数值模拟软件模拟差厚拼焊板盒形件的成形过程，研究变压边力控制对拼焊板成形性能的影响。结果表明，在相同的焊缝移动量下，线性渐增变压边力与定常压边力相比增大了引起焊缝移动的薄侧变形区域材料的长度，缓解了薄侧材料的应变集中，提高了拼焊板成形性能。

英文摘要：

A promising approach to reduce manufacturing costs, increase environmental friendliness and improve the safety of automobiles is to the use tailor-welded blanks （TWBs）. However uneven deformation, weld-bead movement and poorer formability are the important problems that need to be solved during TWB forming, and conventional design techniques can no longer be used for this kind of application. Therefore, new design guidelines have to be devel- oped. The variable blank-holder force （VBHF） can improve the production process and exploit the formability of sheet metal in the production of lighter and more reliable parts. In this paper, a method of enhancing the formability of TWB based on the linearly increasing VBHF over stroke is put forward, and the forming of box with TWBs based on the linearly increasing VBHF varied with stroke control schemes is studied by means of dynamic explicit finite element meth- od. Numerical simulation results demonstrate that the linearly increasing VBHF over stroke control technology is an ef fective method to improve TWBs formability. Compared with the constant blank-holder force, it enlarges the deformation region of thinner side closed with welded-bead, which lead to the weld-bead movement. Consequently the strain of the thinner side is reduced, and the formability of TWBs is improved.