Analysis of the Localization of Damage and the Complete Stress-Strain Relation for Mesoscopic Heterogeneous Rock Under Uniaxial Tensile Loading
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摘要: 岩石在拉应力状态下的力学特性不同于压应力状态下的力学特性．利用细观力学理论研究了细观非均匀性岩石拉伸应力应变关系包括：线弹性阶段、非线性强化阶段、应力降阶段、应变软化阶段.模型考虑了微裂纹方位角为Weibull分布和微裂纹长度的分布密度函数为Rayleigh函数时对损伤局部化和应力应变关系的影响，分析了产生应力降和应变软化的主要原因是损伤和变形局部化.通过和实验成果对比分析验证了模型的正确性和有效性．Abstract: The mechanical behavior of rock under uniaxial tensile loading is different from that of rock under compressive loads.A micromechanics-based model was proposed for mesoscopic heterogeneous brittle rock undergoing irreversible changes of their microscopic structures due to microcrack growth.The complete stress-strain relation including linear elasticity,nonlinear hardening,rapid stress drop and strain softening was obtained.The influence of all microcracks with different sizes and orientations were introduced into the constitutive relation by using the probability density function describing the distribution of orientations and the probability density function describing the distribution of sizes.The influence of Weibull distribution describing the distribution of orientations and Rayleigh function describing the distribution of sizes on the constitutive relation were researched.Theoretical predictions have shown to be consistent with the experimental results.
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