Elastic-Plastic-Damage material models are widely adopted for the numerical modelling of concrete because of their capability of representing pressure sensitive 3D material behaviour considering permanent inelastic deformations as well as degradation of material moduli beyond the elastic range. In this paper, we develop a non-associative multi-surface plastic-damage material model for the 3D solid element based finite element analysis of reinforced concrete structural components. For the non-associative plastic flow, a linear potential function is adopted, while Menetrey–Willam and Rankine surfaces are adopted as the yield surfaces in compression and tension regimes, respectively. The degradation in the material stiffness under cyclic loading is incorporated by the damage component of the material model, which is generally anisotropic and assumed to be directly dependent on the evolution of the plastic strains. This assumption leads to a computationally efficient algorithm in terms of circumventing iterations to equate the stresses between the coupled damage and plasticity components of the material model. The rigorous details of the developed return-mapping methodology considering both the Cutting-Plane as well as the Closest-Point-Projection algorithms are provided. The material model is employed for the structural level analysis, in which case the concrete bulk is modelled by using an Eight-Node, Six-Degrees-Of-Freedom per-node solid element, and the reinforcement bars and stirrups are modelled by using the conventional Two-Node, Six-Degrees-Of-Freedom per-node Euler–Bernoulli beam-bar element. The inelastic behaviour of the reinforcements is determined by using a simpler elasto-plastic-damage based material model under the assumption of uni-axial stress-strain relations. An in-house fortran software is developed for the computer implementation. Comparisons with results from literature are shown for validation purposes. The validation cases include static analyses of a beam and a column under monotonic loading as well as a shear-wall under cyclic loading.

中文翻译：

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使用多表面弹塑性各向异性损伤材料模型对钢筋混凝土结构构件进行三维分析


弹塑性损伤 材料模型被广泛用于混凝土的数值建模，因为它们能够表示压力敏感的 3D 材料行为，考虑永久非弹性变形以及超出弹性范围的材料模量退化。在本文中，我们开发了一种非关联多表面塑性损伤材料模型，用于对钢筋混凝土结构构件进行基于 3D 实体元的有限元分析。对于非缔合塑性流，采用线性势函数，而 Menetrey-Willam 和 Rankine 面分别用作压缩和拉伸状态下的屈服面。材料模型在循环载荷下刚度的退化由材料模型的损伤分量合并，该分量通常是各向异性的，并被认为直接取决于塑性应变的演变。这一假设导致了一种计算高效的算法，即规避迭代，以将材料模型的耦合损伤和塑性分量之间的应力等同起来。本文提供了所开发的返回映射方法的严格细节，该方法考虑了 Cutting-Plane 和 Closest-Point-Projection 算法。材料模型用于结构层面分析，在这种情况下，混凝土体体使用八节点、六自由度的每节点实体单元进行建模，钢筋和箍筋使用传统的双节点、六自由度每节点 Euler-Bernoulli 梁杆单元进行建模。 在单轴应力-应变关系的假设下，通过使用更简单的基于弹塑性损伤的材料模型来确定增强材料的非弹性行为。为计算机实施开发了内部 fortran 软件。显示与文献结果的比较，以便进行验证。验证案例包括单调载荷下梁和柱的静力分析，以及循环载荷下的剪力壁。