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微裂纹演化与汇合是导致准脆性材料损伤及破坏的主要因素.采用复势函数法求解了受远场载荷作用下代表性单元中椭圆微裂纹的变形,讨论了椭圆微裂纹初始取向的变化对微裂纹尺寸增长和偏转角度的影响,并结合微裂纹扩展准则推导了损伤起始的临界应力.基于翼型裂纹扩展过程的能量守恒方程,建立了损伤阶段的本构关系.对裂纹汇合模式进行了讨论,建立了翼型裂纹汇合的几何模型,由翼型裂纹汇合的临界条件给出了断裂失效应变,最后给出了与细观结构演变过程相对应的本构模型,并应用该模型计算了岩石类材料单轴压缩下的应力应变曲线,与实验结果吻合良好.
The evolution and convergence of microcracks are the main factors leading to the damage and destruction of the quasi-brittle materials. The complex potential function method is used to solve the deformation of the elliptical microcracks in the representative cells under the far-field loading. The change of the initial orientation of the elliptical microcracks The influence of microcrack size growth and deflection angle is deduced and the critical stress of damage initiation is deduced based on the microcrack propagation criterion.Based on the energy conservation equation of airfoil crack propagation process, the constitutive relation of damage phase is established. The crack confluence mode Discussed the establishment of a geometric model of airfoil crack confluence, given the fracture failure strain by the critical conditions of airfoil crack confluence, and finally given the constitutive model corresponding to the evolution of meso-structure, and applied the model to calculate The stress-strain curve of rock-like material under uniaxial compression is in good agreement with the experimental results.