The present article develops two formulations of zero‐thickness mortar/interface finite elements for unmatched meshes, which are implemented in a unified theoretical framework. The first one is displacement‐based and may be considered a natural extension of the traditional zero‐thickness interface element to the case of unmatched meshes on each side of the discontinuity. The other one is hybrid, with an interpolation of stress tractions along the contact surface, which coexists with the standard displacement interpolations of the continuum surfaces in contact. The hybrid formulation shares some features with mortar formulations found in the literature of contact‐friction, and turns out fully equivalent to the displacement‐based in the particular case of matched nodes and uniform, linear elastic behavior. Flow chart diagrams for the numerical implementation are also presented and discussed, as well as some examples of application.

中文翻译：

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零厚度砂浆/界面单元基于位移的混合配方，适用于不匹配的网格，并应用于断裂力学

本文针对无匹配网格，开发了两种厚度为零的砂浆/界面有限元的公式，它们在统一的理论框架内实现。第一个是基于位移的，并且可以认为是传统零厚度界面元素在不连续面的每一侧都没有匹配网格的情况下的自然扩展。另一个是混合的，沿着接触表面的应力牵引插值与接触的连续面的标准位移插值并存。混合配方与接触摩擦文献中发现的砂浆配方具有某些特征，在匹配节点和均匀线性弹性行为的特定情况下，完全等同于基于位移的配方。