The models developed for masonry and historical structures in the literature are usually classified into macromodels considering masonry as an equivalent continuum; and micromodels in which brick, blocks, or stones and mortar joints are represented explicitly. In this second category, many contributions dealt with regular bond masonry for which the geometrical description and the discretization are rather straightforward. For irregular masonry structures however, even though both finite element method (FEM) and discrete element method (DEM) approaches have been developed, obtaining a versatile geometry representation and its discretization remains much less straightforward. This becomes an important issue nowadays with the availability of image acquisition techniques, based on which computational models could be derived. The present contribution proposes an automated methodology to produce a line description of the mortar joints of an irregular masonry blocks/stones and mortar assembly, which can subsequently be used in modeling approaches. The starting point of the development is a generation technique based on inclusions packings which uses distance fields to the nearest neighboring inclusions to describe an assembly of blocks or stones geometrically. It is shown that such an assembly and the corresponding distance fields can be used to extract efficiently and in an automated way a line or lumped description of the corresponding mortar joint based on the concept of a medial axis. This line description can subsequently be used to define computational models. This is illustrated by the automated generation of FEM models that represent mortar joints by interface elements equipped with a cohesive law. Simulations on representative volume elements (RVEs) and on a wall are shown to illustrate the methodology that paves the way towards the image-based modeling of irregular masonry structures through the automated generation of cohesive zone-based models.

中文翻译：

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对不规则砌体裂缝进行基于图像的自动化粘性区域建模

文献中为砌体和历史结构开发的模型通常分为宏观模型，将砌体视为等效的连续体；以及明确表示砖、块或石头和灰缝的微模型。在第二类中，许多贡献涉及常规粘结砌体，其几何描述和离散化相当简单。然而，对于不规则砌体结构，尽管有限元法 (FEM) 和离散元法 (DEM) 方法均已开发出来，但获得通用的几何表示及其离散化仍然不那么简单。随着图像采集技术的出现，这成为一个重要的问题，基于图像采集技术可以导出计算模型。目前的贡献提出了一种自动化方法来生成不规则砌块/石头和砂浆组件的砂浆接缝的线条描述，随后可用于建模方法。开发的起点是基于内含物堆积的生成技术，该技术使用到最近的相邻内含物的距离场来以几何方式描述块或石头的组合。结果表明，这种组件和相应的距离场可用于基于中轴的概念以自动方式有效地提取相应灰缝的线或集中描述。该线路描述随后可用于定义计算模型。这可以通过自动生成 FEM 模型来说明，这些模型通过配备内聚定律的界面元素来表示砂浆接缝。对代表性体积单元 (RVE) 和墙壁上的模拟展示了通过自动生成基于粘性区域的模型，为不规则砖石结构基于图像的建模铺平道路的方法。