超高强钢点焊结构拉剪试验及数值仿真

Experiments and numerical simulation on spot-welded structure of ultra-high strength steel

以超高强淬火钢22MnB5搭接型点焊结构为研究对象,通过拉剪试验、光学试验和维氏硬度测试,获得了点焊结构的部分力学参数.在ANSYS中进行强度仿真,并与试验结果进行对比.结果表明,将点焊模型分为焊核、塑性环、母材三部分的有限元模型是合理的.同时仿真结果还表明点焊结构交界面的塑性环边缘处是最薄弱的位置,结构失效主要由切应力所引起,并分析了部分尺寸参数对结构强度的影响,当焊核半径、两板重叠长度与板厚越大,结构的最大Von Mises应力值就越低,但增大到一定程度后,其影响降低,为焊接工艺参数的优化提供参考.

Mechanical parameters of spot-welded structure of 22MnB5 ultra-high strength steel were obtained by a series of experiments including tensile-shear testing,optical experiment and the vickers-hardness testing. In addition,intensity simulations on the spot-welded structure were carried out by software ANSYS. The good agreement of simulation results with experimental data confirmed the rationality of the three-phrase finite element model of the spot-welded structure,which consist of weld nugget,plastic ring and base metal. Based on the simulation results,the plastic ring edge of the spot-welded structure interface is the weakest position,where the structural failure is mainly caused by the shear stress. For purpose of spot-welded structure optimization, the dependence of strength of the spot-welded structures on their structure parameters were analyzed. The simulations results uncovered that the maximum Von Mises stress of the structure can be reduced to a considerable extent by increasing radius of the weld nugget,the overlapping length of the two sheets and the thickness of the plates.