Abstract:  A comparative analysis was conducted on the fracture splitting processing performance of two types of high-strength connecting rods, 36MnVS4 and 46MnVS5, which were made from non-quenched and tempered materials. The reasons that affected the quality of connecting rod cracking were explored, and the boundaries for connecting rods cracking processing were optimized. The impacts of the connecting rod structures on the fracture-splitting processing performance were analyzed as well. The distribution characteristics of principal stresses and plastic strains at the roots of the cracking grooves were analyzed, and the crack initiation positions for connecting rods made of different materials were determined. The crack propagation processes of the connecting rods were simulated using the finite element software ABAQUS and FRANC3D, and a comparative analysis was conducted. The loading speed for the cracking processing of the 36MnVS4 materials was optimized. The impacts of the connecting rod structures on the cracking performance were analyzed.The results indicate that under the same boundary conditions, the cracking performance of 46MnVS5 material is better, with the tendency to have a unique crack initiation position, low notch sensitivity, good fracture brittleness, faster crack propagation speed, and higher required crack load. At a loading speed of 25 mm/s, the cracking performance of 36MnVS4 material improves. Connecting rod structures with smaller theoretical fracture surface area exhibit relatively better cracking performance.

Key words:  , fracture splitting performance, crack initiation, crack propagation, loading speed, theoretical fracture surface

摘要： 针对高强度的36MnVS4和46MnVS5两种裂解连杆用非调质材料，开展了连杆裂解加工性能的对比分析，探究了影响连杆裂解质量的原因，并对连杆裂解加工的边界作出了优化，分析了连杆结构对裂解加工性能的影响。根据连杆实际裂解加工特性，设置了有限元模拟的边界条件。通过分析裂解槽根部的主应力和塑性应变的分布特征，获得了不同材料连杆的裂纹萌生位置；用ABAQUS和FRANC3D两个有限元软件模拟了连杆裂解的裂纹扩展过程，并进行了对比分析；优化了36MnVS4材料裂解加工的加载速度；分析了连杆结构对裂解性能的影响。研究结果表明：在相同边界条件下，46MnVS5材料裂解性能较好，裂纹萌生位置趋向于唯一，缺口敏感性低、断裂脆性较好、裂解速度较快，所需的裂解载荷更大；在25 mm/s的加载速度下，36MnVS4材料的裂解性能得到优化；理论断裂面面积较小的连杆结构裂解性能相对较好。

关键词: 裂解性能, 裂纹萌生, 裂纹扩展, 加载速度, 理论断裂面