A coupled damage-plastic based constitutive model using a traction-separation law is developed in this study to simulate the behaviour of mortar joints in masonry structural panels subjected to in-plane (2D) and out-of-plane (3D) loading. A smooth hyperbolic failure surface is used to develop the interface material model, which is implemented numerically using a fully implicit backward Euler integration technique is unconditionally stable. To further improve the accuracy and robustness of the interface model, an adaptive sub-stepping scheme and associated consistent tangent operator are formulated considering the effects of damage and plastic deformations. This is beneficial for simulating full-scale masonry structures because the size of load step for some locations with higher deformations can be significantly larger than other locations. The model is first validated using a single cohesive element within a finite-element modelling platform, to assess its behaviour under all possible deformation modes: tensile, compressive with shear and tensile-shear mix-mode behaviour. The cyclic response of a masonry couplet is then simulated to assess model performance in the unloading scenario. Finally, the model is applied to masonry structural walls for simulating their failure response under in-plane and out-of-plane loads, and a good correlation with the experimental results is observed.

本研究开发了一种使用牵引-分离定律的基于损伤-塑性的耦合本构模型，以模拟砖石结构板中砂浆接缝在面内 (2D) 和面外 (3D) 载荷下的行为。光滑的双曲破坏面用于开发界面材料模型，该模型使用完全隐式后向欧拉积分技术在数值上实现是无条件稳定的。为了进一步提高界面模型的准确性和鲁棒性，考虑到损伤和塑性变形的影响，制定了自适应子步进方案和相关的一致切线算子。这有利于模拟全尺寸砌体结构，因为某些变形较高的位置的载荷步长可能明显大于其他位置。该模型首先在有限元建模平台内使用单个内聚单元进行验证，以评估其在所有可能的变形模式下的行为：拉伸、压缩和剪切以及拉伸-剪切混合模式行为。然后模拟砌体对的循环响应，以评估卸载场景中的模型性能。最后，将该模型应用于砌体结构墙体，模拟其在面内和面外荷载作用下的破坏响应，并与实验结果具有良好的相关性。然后模拟砌体对的循环响应，以评估卸载场景中的模型性能。最后，将该模型应用于砌体结构墙体，模拟其在面内和面外荷载作用下的破坏响应，并与实验结果具有良好的相关性。然后模拟砌体对的循环响应，以评估卸载场景中的模型性能。最后，将该模型应用于砌体结构墙体，模拟其在面内和面外荷载作用下的破坏响应，并与实验结果具有良好的相关性。