冲击荷载下管壁开孔对方形钢管动态承载力的影响

Influence of pipe wall opening on dynamic bearing capacity of square steel tube under impact load

建立管壁开孔方形钢管的数值模型,模拟其在低速冲压和高速冲压下的变形模式和应力变化,以此分析管壁开孔及冲压速度对方形钢管冲击动力学性能的影响。分析结果显示:钢管在冲压变形的早期阶段,初始变形聚集区随着管壁开孔率增大而趋于均匀;钢管冲压变形的后期,其变形模式与冲压速度有关,即低速冲压时钢管呈侧向弯扭变形,高速冲压时钢管呈波浪式折叠挤压变形;钢管的p-效应在低速冲压下较为明显。在应力变化方面,低速冲压下,管壁开孔可以提升小变形钢管的冲压承载力,而大变形钢管的冲压承载力随开孔率增加而降低;高速冲压下,管壁开孔可明显提升钢管的冲压承载力,且方形钢管存在明显的应变率效应。

The numerical model of square steel tube with pipe wall opening is established to simulate the deformation mode and stress variation under low speed stamping and high speed stamping, so as to analyze the influence of pipe wall opening and punching speed on the impact dynamic performance of square steel pipe. The analysis results show that in the early stage of stamping deformation, the initial deformation and accumulation area tends to be uniform with the increase of the opening ratio of the pipe wall; in the later stage of steel pipe stamping deformation, the deformation mode is related to the pressing speed, that is, the steel pipe is formed at low speed stamping. The lateral bending and torsion deformation, the steel pipe is wave-folded and extruded when high-speed stamping; the p-effect of the steel pipe is more obvious under low-speed stamping. In terms of stress variation, under low-speed stamping, the opening of the pipe wall can improve the stamping capacity of the small-deformed steel pipe, while the punching capacity of the large-deformed steel pipe decreases with the increase of the opening ratio; under high-speed stamping, the pipe wall opening can be significantly improved. The stamping capacity of the steel pipe, and the square steel pipe has a significant strain rate effect.