外部爆炸载荷下表面粗糙度对45钢柱壳剪切带行为的影响

Effect of Surface Roughness on Shear Band Behavior of 45 Steel Cylindrical Shell under External Explosion Load

通过厚壁圆筒爆轰坍塌实验和有限元数值模拟,研究了45钢柱壳内壁表面粗糙度对其剪切带行为的影响。实验结果表明:外爆加载下,金属柱壳内壁表面粗糙度显著改变试样剪切带的成核位置和数量;当柱壳内壁表面粗糙度增大时,剪切带的数量和长度均增加,部分剪切带的扩展速度也增大;而当柱壳内壁表面的峰谷单元的平均宽度减小时,其剪切带的成核点数量增加,相邻剪切带之间的相互作用增强。有限元模拟和分析结果表明,柱壳中的最大剪切应力产生于柱壳内壁表面峰谷单元的谷底两侧,表面粗糙度的增大和峰谷单元平均宽度的减小均会提升柱壳内表面的剪切应力,促进柱壳中剪切带的成核和扩展,进而导致剪切带成核数量增多,主剪切带发展加快,剪切带屏蔽效应增强。

The effects of different inner wall surface roughness of 45 steel cylindrical shell on its shear band behavior were studied based on detonation collapse experiments of thick walled cylinder and finite element numerical simulation.The experimental results show that the surface roughness of the inner wall of the metal cylindrical shell significantly changes the nucleation position and the quantity of the shear bands under external explosion load.When the surface roughness of the inner wall of the cylindrical shell increases,the quantity and length of the shear bands increase,and the propagation speed of some shear bands increases as well.When the average width of the valleys of the inner wall decreases,the interaction between adjacent shear bands enhances with the increase of the nucleation points in the shear band.The finite element simulation and the theoretical analysis show that the maximum shear stress in the cylindrical shell generates on both sides of the valley bottom of the inner wall in the cylindrical shell.The shear stress on the inner surface of the cylindrical shell is enhanced with the increase of surface roughness,or with the decrease of average width of valleys.As the shear stress augments,the nucleation and the propagation of shear bands in the cylindrical shell are promoted,the nucleation quantity of the shear bands increase,the development of the main shear bands accelerate,and the shielding effect of the shear bands enhance.