基于能量守恒修正的混凝土损伤本构模型

Concrete damage constitutive model based on energy conservation

为了改进传统的混凝土损伤本构模型,采用TAW-2000试验系统对养护3 d和28 d的混凝土试样进行了三轴力学特性试验,并通过混凝土加载过程中的能量计算方法,确定了混凝土变形过程中的总能量、弹性能和耗散能,根据能量守恒原理建立了可描述混凝土应力-应变关系的修正本构模型。通过模型曲线的对比验证了所建立本构模型的合理性和优越性,并明确了模型参数的物理意义。结果表明:以往本构模型曲线在混凝土应力-应变曲线峰后阶段具有较大的偏离度,而修正的本构模型曲线在应力-应变曲线峰后段的吻合度要更优。模型参数γ可较好地反映混凝土的脆性和延性特征,模型参数n可较好地反映混凝土的强度特征。

In order to study the deformation characteristics of concrete under different confining pressures and different curing cycles,the TAW-2000 test system was used to conduct triaxial mechanical property tests on concrete samples cured for 3d and 28d.The total energy,elastic energy and dissipated energy in the concrete deformation process were determined by the energy calculation method during the concrete loading process.According to the energy conservation principle,a constitutive model that can describe the stress-strain relationship of concrete was obtained.The comparison of model curves proves the rationality and superiority of the established constitutive model.The physical meaning of new model parameters is clarified.The results show that the previous models’curves have a large deviation at the post-peak stage of the concrete stress-strain curve.However,the degree of fitting of the new model curve at the post-peak stage is higher.The model parameterγcan better reflect the brittleness and ductility characteristics of concrete.The model parameter n can better reflect the strength characteristics of concrete.