裂纹连续度对非均质材料中雁行裂纹扩展的影响

应用材料破裂过程分析(MFPA2D)系统,通过对非均质材料试样中预置的雁行裂纹在单轴压缩下裂纹扩展、演化过程的数值模拟,研究了裂纹连续度的变化对裂纹尖端邻域应力场及裂纹扩展模式的影响,同时分析了连续度变化对裂纹起裂应力及强度所造成的影响·数值模拟结果表明随裂纹连续度的减小,裂纹内尖端的应力场逐渐由拉应力场过渡为压应力场,裂纹的扩展模式相应地经历拉模式(T)、拉剪模式(T S)及压模式(C),裂纹扩展的起始角度与最大压应力之间的角度也逐渐增大·此外,数值模拟结果还表明裂纹尖端的起裂应力大致为试样极限强度的1/2～1/3·

Influence of Crack Continuity on Propagation of En Echelon Cracks in Heterogeneous Materials

Using a Material Failure Process Analysis (MFPA^2D) code, the influence of crack continuity in heterogeneous materials containing two existing parallel flaws under uniaxial loading is numerically studied. The numerical simulation reproduces the stress field in the vicinity of cracks and the processes of propagation and coalescence of cracks during compression. The numerical simulation results showed that, with the decrease of the crack continuity, the stress field between the tips of internal cracks gradually changes from tensile stress to compression stress and the propagation mode of cracks also changes from tensile mode(T), tensile-shear mode(T-S) to compressive mode(C), and the initiation angle between the flaw and the direction of the maximum compression increases gradually as well. In addition, the initiation stress on the tips of cracks is about l/2-1/3 of the failure strength of the specimens.