Numerical Analysis of the Crack-Tip Stress Field in Pure Aluminum Sheet Constrained by Interfaces
约束条件下界面纯铝层裂尖应力场的数值分析

Elastic-plastic large deformation finite element (FE) analysis was conducted on the crack-tip stress field of pure Al sheet in LY12/A1/LY12 sandwich specimen with a strength mismatch and fatigue pre-crack under plane strain condition. The results show that, in the condition of small scale yielding (SSY), the peak value of loadings linearly increases with decreasing pure Al sheet thickness. Plastic deformation zone in Al sheet constrained by interfaces will spread along the crack-tip ligament parallel to the two interfaces instead of a spindle-like in a constraint-free metal, and this tendency becomes more remarkable with decreasing pure Al thickness. The maximum triaxial constraint and the tensile stress continue to rise with either increasing load or decreasing pure Al thickness. The high triaxial constraint in the Al sheet results in cavitations and micro-cracks as well as brittleness even local cleavage of pure Al sheet.