基于应变空间的碾压混凝土各向异性损伤本构模型

根据碾压混凝土材料的力学特性和损伤拉压显著不同的特点,分别在拉应变和压应变空间建立了碾压混凝土的本构关系和损伤演化方程。在拉应变空间,碾压混凝土的变形特性表现为脆弹性,考虑弹性与损伤耦合,应用正交各向异性损伤理论描述碾压混凝土的刚度退化和应变软化;在压应变空间,考虑弹塑性与损伤耦合,应用内时理论来描述碾压混凝土的弹塑性特性,正交各向异性损伤理论来描述微裂缝扩展引起的刚度退化和应变软化,内时理论没有屈服面,使模型的参数和方程大大减少,从而简化了非线性计算过程。计算结果表明,该模型能够较好地描述碾压混凝土在单轴和多轴加载下的性质。

ANISOTROPIC DAMAGE CONSTITUTIVE MODEL FOR ROLLER COMPACTED CONCRETE IN STRAIN SPACE

The constitutive laws and damage evolution equations of Roller Compacted Concrete (RCC) are established in tensile and compressive strain spaces, respectively. In tensile strain space where the material is elasto-brittle, the coupling of elasticity and damage is considered and the behavior of stiffness degeneration and strain softening is described by orthotropic damage theory. In compressive strain space where the material is elasto-plastic, the elasto-plasticity is described by endochronic theory and the behavior of stiffness degeneration and strain softening due to microcrack propagation is described by orthotropic damage theory. No yield surface is needed in endochronic theory, hence the number of parameters and equations in the model is reduced significantly and the nonlinear calculation is simplified. Good agreement is observed between the predicted values using the proposed model and the experimental results of RCC under uniaxial and multiaxial loading.