车身覆盖件点焊结构虚拟节点建模及应用

New FE modeling approach to spot welding joints of automotive panels and applications

为了研究大量焊点快速建模及保证焊点的位置精度问题,提出了虚拟节点法以模拟点焊结构。首先在实际焊点位置处建立参考点,并把该参考点沿焊接面的法线方向向两焊接面投影,得到两个虚拟节点;焊接单元由该虚拟节点对构成,并在两虚拟节点之间引入一短梁单元来模拟焊接关系。其次,在每个虚拟节点和其周围网格节点之间建立分布耦合约束,通过耦合关系实现虚拟节点和其周围网格节点运动上的协调。经试验与比较表明,该方法仿真结果与试验结果一致性较好,比传统方法更有效地模拟实际焊点的力学行为,证实了虚拟节点法应用于模拟点焊结构的可行性。

In order to investigate the problem on how a large number of spot-weld models can be established efficiently and how the positional precision of spot-welds can he ensured, virtual-node method was presented to simulate welding spots. In this method, firstly, a reference point established in the real location of the welding spot was projected onto two welding planes along their normal directions to obtain two virtual nodes; the welding element was composed of such a pair of virtual nodes, and a short beam element connecting the two virtual nodes was introduced to simulate the welding relation. Secondly, the distributive coupling constraints were built between each virtual node and the surrounding nodes on the surface in its immediate neighborhood, and then the motion of the virtual node was coupled to the motion of the nodes in this region by the constraints. The results showed the virtual-node method had a good accordance with the experimental results, and the mechanical property of the real welding spots could be more effectively simulated than the traditional method. It proved of the feasibility of the virtual-node method in effectively simulating welding spots.