Interfacial debonding constitutive model and XFEM simulation for mesoscale concrete
Interfacial debonding constitutive model and XFEM simulation for mesoscale concrete
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DOI：
10.1016/j.compstruc.2020.106373
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发表时间：
2021
影响因子：
4.7
通讯作者：
Xiaozhou Xia;Fei Chen;X. Gu;N. Fang;Qing Zhang
中科院分区：
文献类型：
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作者：
Xiaozhou Xia;Fei Chen;X. Gu;N. Fang;Qing Zhang
混凝土中水泥浆体与集料之间的界面过渡区对混凝土的宏观力学性能起着重要的作用。它通常表现为一个薄弱环节，限制了混凝土的材料抗力。本文基于扩展有限元法和界面本构关系，建立了一个从细观结构特征到宏观力学性能的数值桥梁。为此，首先，牵引分离本构反映软化和膨胀行为的ITZ的开发。第二，两阶段配置模型，即，水泥浆体/集料界面处插入界面处的混凝土组分分布特征。同时，利用扩展有限元中强不连续位移模式的统一框架，分析了界面区的三种状态，粘滞、半分离和完全脱离，可自然捕获。第三，通过对含单个夹杂物板的拉伸分析，验证了夹杂物问题的扩展有限元方法的有效性，并通过分析界面处受复杂压缩和剪切作用时的牵引和变形演化，验证了界面处本构模型的优越性。最后，该方法被应用于调查的ITZ因素，如初始刚度，强度，和能量释放率对混凝土的宏观力学性能的影响。
The interfacial transition zone (ITZ) between cement paste and aggregates in concrete plays an important role in the macro-mechanical properties of concrete. It generally exhibits as a weak link, restricting the material resistance of concrete. The present work aims at proposing a numerical bridge from mesostructure features to macro-mechanical properties based on the extended finite element method (XFEM) and interfacial constitutive. For this end, first, a traction-separation constitutive reflecting the softening and dilatation behavior of ITZ is developed. Second, the two-phase configuration model, i.e., cement paste/aggregate with ITZ inserted as the interface, is adopted to characterize the concrete constituent distribution. Also, by using a unified framework of strong discontinuous displacement mode in XFEM, three states of ITZ, i.e., sticking, semi-separation and complete disengagement, can be captured naturally. Third, the elaborated XFEM approach for inclusion problem is verified by analyzing a plate with a single inclusion under tension, and the merits of the ITZ constitutive model are also verified by analyzing the traction and deformation evolution of ITZ suffering complex compression and shear. Finally, the approach is applied to investigate the effect of ITZ factors such as the initial stiffness, strength, and energy release rate on the macro-mechanical properties of concrete.