混凝土的细观损伤理论及其数值模拟

The Micromechanical Damage Theory for Concrete withNumerical Simulations

本文建立了拉伸荷载作用下混凝土的二维细观损伤的本构理论，采用有效场方法考虑混凝土的裂纹相互作用，分析了混凝土随外加应力场的损伤演化过程，求出了损伤柔度张量的表达式，在此基础上对混凝土的细观损伤特性进行了数值模拟．由于微裂纹的扩展和裂纹之间的相互作用，混凝土的柔度表现为非对称的和各向异性的。数值分析表明，本文模型的计算结果介于Ｔａｙｌｏｒ方法和自恰方法之间，与实验结果具有较好的一致性，尤其是当裂纹密度较大时，本文的结果能更好地模拟实验结果。因此，当裂纹密度较大时，必须考虑裂纹的相互作用。

This paper presents the two-dimensional micromechanical damageconstitutive theory for concrete in tensile loadings.The effective field method is employed to analyze the crack interaction in concrete.The damage evolution of concreteis described as a function of the external loads.The corresponding damage-inducedinelastic compliances are subsequently constructed.Finally,the micromechanial damagesimulations are carried out for both the proposed model and Tayloy's model. Due tocrack propagating and crack interacion,overall compliances of concrete arenonsyrmtric and anisotropic.The numerical simulations show that the simulated curves ofthe proposed model are between Taylor model's and self-consistent model 's and canagree very well with available experimental data,especially in the case of large crackdensity. Therefore, if the crack density is quite large,the crack interaction has to beconsidered.