Some of the current concrete damage plasticity models in the literature employ a single damage variable for both the tension and compression regimes, while a few more advanced models employ two damage variables. Models with a single variable have an inherent difficulty in accounting for the damage accrued due to tensile and compressive actions in appropriately different manners, and their mutual dependencies. In the current models that adopt two damage variables, the independence of these damage variables during cyclic loading results in the failure to capture the effects of tensile damage on the compressive behavior of concrete and vice-versa. This study presents a cyclic model established by extending an existing monotonic constitutive model. The model describes the cyclic behavior of concrete under multiaxial loading conditions and considers the influence of tensile/compressive damage on the compressive/tensile response. The proposed model, dubbed the enhanced concrete damage plasticity model (ECDPM), is an extension of an existing model that combines the theories of classical plasticity and continuum damage mechanics. Unlike most prior studies on models in the same category, the performance of the proposed ECDPM is evaluated using experimental data on concrete specimens at the material level obtained under cyclic multiaxial loading conditions including uniaxial tension and confined compression. The performance of the model is observed to be satisfactory. Furthermore, the superiority of ECDPM over three previously proposed constitutive models is demonstrated through comparisons with the results of a uniaxial tension-compression test and a virtual test.

文献中一些当前的混凝土损伤可塑性模型对拉伸和压缩状态都采用单个损伤变量，而其他一些高级模型则采用两个损伤变量。具有单个变量的模型在考虑由于适当不同方式的拉伸和压缩作用而产生的损坏及其相互依赖性方面存在固有的困难。在采用两个损伤变量的当前模型中，这些损伤变量在循环载荷期间的独立性导致无法捕获拉伸损伤对混凝土的压缩行为的影响，反之亦然。这项研究提出了通过扩展现有的单调本构模型而建立的循环模型。该模型描述了混凝土在多轴载荷条件下的循环行为，并考虑了拉伸/压缩损伤对压缩/拉伸响应的影响。提议的模型被称为增强混凝土损伤可塑性模型（ECDPM），是对现有模型的扩展，该模型结合了经典可塑性和连续损伤力学的理论。与大多数先前对同一类别的模型进行的研究不同，所提议的ECDPM的性能是使用混凝土试样的实验数据在单轴拉伸和有限压缩的循环多轴载荷条件下获得的材料水平上进行评估的。观察到该模型的性能令人满意。此外，