考虑残余变形影响的混凝土疲劳损伤本构模型

从分析混凝土材料的基本损伤机制出发,考虑疲劳荷载作用下混凝土的损伤累积和残余变形,推导了由Helmholtz自由能表示的混凝土本构方程,根据变分原理建立了基于能量的混凝土疲劳损伤本构模型.并根据疲劳过程中残余变形的发展规律,定义了物理意义明确的残余变形影响因子,并将其与混凝土变形模量损伤因子一同融入混凝土疲劳损伤本构模型中,为混凝土疲劳行为的计算机分析提供了一种更为精确、简化的混凝土疲劳本构模型.试验数据和数值算例的对比误差不超过3%,从而验证了该模型的准确性与适用性.

Fatigue Damage Constitutive Model of Concrete Considering the Effect of Residual Deformation

On the basis of the fundamental damage mechanism of concrete, damage accumulation and residual deformation of concrete under fatigue loading were considered, and the constitutive equation of concrete expressed by Helmholtz free energy was derived. An energy based fatigue damage constitutive model was then proposed by using the variation principle. Meanwhile, based on the development law of the residual deformation of concrete under fatigue load, the influencing coefficient of the residual deformation with definite physical meaning was defined, which was then included into the plastic damage constitutive model of concrete together with the damage factor of deformation modulus in order to provide a more accurate and convenient fatigue constitutive model. To verify the accuracy and applicability of the proposed model, the results of the numerical examples were compared with the experimental data, where no more than 3% of error was observed.