20(上标 #)钢动态拉伸断裂行为及其临界损伤度研究

The influence of the impact stress and the tensile strain rate on the dynamic tensile fracture of 20(superscript #) steel was investigated experimentally by plate impact spall tests. Based on the damage function model, numerical calculations about the spall tests were performed. The results indicated that the critical fracture damage D(subscript ƒ) is independent on the impact stress and the tensile strain rate. By means of an explicit nonlinear dynamic finite element computer code Ls-dyna, spallation in cylindrical steel tube loaded by sliding-implosion had been studied with the introduction of damage function model. Results demonstrated that D(subscript ƒ) determined by plate impact and numerical calculation is applicable to predict the dynamic tensile fracture behavior in metal cylinders under the complex loadings as well. Therefore, D(subscript ƒ) may be regarded as a material constant to identify the intrinsic characteristic of the dynamic tensile fracture.