Leonetti Lorenzo, Fantuzzi Nicholas, Trovalusci Patrizia, Tornabene Francesco
DINCI-Department of Civil Engineering, University of Calabria, 87036 Rende, Italy.
DICAM-Department, School of Engineering and Architecture, University of Bologna, 40136 Bologna, Italy.
Materials (Basel). 2019 Mar 5;12(5):758. doi: 10.3390/ma12050758.
The aim of the present work was to investigate the mechanical behavior of orthotropic composites, such as masonry assemblies, subjected to localized loads described as micropolar materials. Micropolar models are known to be effective in modeling the actual behavior of microstructured solids in the presence of localized loads or geometrical discontinuities. This is due to the introduction of an additional degree of freedom (the micro-rotation) in the kinematic model, if compared to the classical continuum and the related strain and stress measures. In particular, it was shown in the literature that brick/block masonry can be satisfactorily modeled as a micropolar continuum, and here it is assumed as a reference orthotropic composite material. The in-plane elastic response of panels made of orthotropic arrangements of bricks of different sizes is analyzed herein. Numerical simulations are provided by comparing weak and strong finite element formulations. The scale effect is investigated, as well as the significant role played by the relative rotation, which is a peculiar strain measure of micropolar continua related to the non-symmetry of strain and work-conjugated stress. In particular, the anisotropic effects accounting for the micropolar moduli, related to the variation of microstructure internal sizes, are highlighted.
本工作的目的是研究正交各向异性复合材料（如砌体结构）在作为微极材料的局部荷载作用下的力学行为。众所周知，微极模型在模拟存在局部荷载或几何不连续情况下微结构固体的实际行为时是有效的。与经典连续体及其相关的应变和应力度量相比，这是由于在运动学模型中引入了一个额外的自由度（微旋转）。特别是，文献表明砖/砌块砌体可以令人满意地建模为微极连续体，在此将其假定为参考正交各向异性复合材料。本文分析了由不同尺寸砖块正交排列制成的面板的面内弹性响应。通过比较弱有限元和强有限元公式进行了数值模拟。研究了尺度效应以及相对旋转所起的重要作用，相对旋转是微极连续体的一种特殊应变度量，与应变和功共轭应力的非对称性有关。特别是，突出了考虑与微结构内部尺寸变化相关的微极模量的各向异性效应。
