中缸体焊接接头断裂行为的有限元分析

Finite Element Analysis of Fracture Behavior of Welded Joints in Cylinder

液压支架中缸体是以焊接方式连接,那么焊缝位置的选择对于中缸体的使用寿命具有重要的影响。这样笔者分析了不同位置焊接接头的受力特点、应力强度因子以及与其相关的裂纹扩展速率(寿命评估)等断裂参数。通过不同位置焊接接头的有限元分析可知:焊接接头在中缸体中间时对压力的敏感性较强。应力强度因子的计算结果表明:对两种位置焊接接头的应力强度因子值的比较可以发现,焊接接头在中缸体中间时其应力强度因子值小于在中缸体端部时的应力强度因子值,说明了焊接接头在中间位置时抗疲劳和断裂能力较强。裂纹扩展速率试验结果表明:热影响区裂纹扩展速率大于焊缝的裂纹扩展速率,因此裂纹扩展沿着熔合线扩展的可能性更大。

The cylinder of hydraulic support is connected by welding,so the choice of the weld locations has an important impact on the life of the cylinder.The force characteristics,stress intensity factor and crack growth rate of the welded joints in different locations were analyzed.According to the finite element models analysis of the welded joints,the results show that when the welded joints are in the middle of the cylinder,they have strong sensitivity to the stress.By the calculation and contrast of the stress intensity factor of welded joints in different position,it is found that the stress intensity factor of the welded joint in the middle of the cylinder is smaller than in the end.It can be speculate that the resistance to fatigue and fracture of the middle welded joints is much stronger.The crack growth rate experiments were also carried out.The results show that the crack growth rate of the HAZ is bigger than welds,so it is more likely that the crack expands along the fusion line.