Browsing by Author "Honnalli, S."

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Determination of Effective Properties of Masonry Using FEA-Based Homogenization Approach
(Springer Science and Business Media Deutschland GmbH, 2024) Honnalli, S.; Pavan, G.S.
Masonry is a widely used construction method. Masonry is typically heterogeneous in nature, consisting of bricks and mortar joints with varying mechanical properties. Thus, masonry will behave like a composite material with orthotropic material characteristics. However, the material heterogeneity of masonry will be ignored in the analysis of masonry structures, assuming it is a homogeneous, isotropic element, which is not true and leads to incorrect assessment. Thus, it is necessary to predict the orthotropic properties of masonry for the accurate assessment of masonry structures. On the other hand, predicting such orthotropic characteristics of masonry becomes a complex task, due to the presence of material heterogeneity. Therefore, researchers adopted numerical homogenization methods to assess the orthotropic properties of masonry. In this study, the FEA-based homogenization method is proposed to predict the orthotropic properties of masonry. Toward this direction, a small periodic part called the repetitive unit cell (RUC) of the English bond masonry prism available in the literature study is considered and modeled in ABAQUS software for the homogenization process. The constituents of RUC are modeled as a continuum element with linear and isotropic behavior. A series of linear stress analyses of RUC has been conducted using six-far field unit strains. The effective orthotropic properties of masonry can be predicted using the stressâ€“strain relationship obtained from the linear stress analysis of masonry RUC. Finally, the results obtained from the numerical homogenization process are validated with the experimental results available in the literature study. Â© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Determining elastic properties of CSEB masonry using FEA-based homogenization technique
(Elsevier Ltd, 2023) Shalini, S.; Honnalli, S.; Pavan, G.S.
The world today is embracing a sustainable approach in all sectors. The construction industry is grappling with the problem of minimizing energy consumption and lowering carbon emissions involved in the manufacture of construction materials. Soil blocks are an alternative to fired clay bricks. Soil bricks are inexpensive, recyclable, environmentally friendly, and provide better thermal comfort. However, masonry walls built with soil blocks have several drawbacks. They are bulky, have poor durability properties and their strength capacity reduces significantly when saturated due to rain. The remedy for this problem is a Cement Stabilized Earth Block (CSEB). An engineered mixture of soil-sand-cement-moisture compacted at predefined levels offers superior strength and durability properties. The percentage of cement added is minimal in comparison to the soil-sand mixture content. In this study, a numerical model to predict the elastic properties of masonry comprised of CSEB and soil–cement mortar is developed. Both the constituents, CSEBs, and soil–cement mortar have different elastic properties. The presence of bed joints and perpends lends orthotropic behavior to masonry. The present study considers the Finite element analysis (FEA)-based homogenization technique to predict the elastic properties of CSEB masonry. A small periodic part of masonry called a repetitive unit cell (RUC) is considered, which is representative of the block-mortar arrangement in masonry. The three-dimensional masonry RUC is modelled using FE-based ABAQUS-CAE software. A user-defined Python script is developed to apply PBCs (Periodic boundary conditions) to RUC. The six far-field unit strains are applied to the RUC model in three normal and three shear directions. Finally, volume-averaged stress components are computed to determine the elastic properties. The modulus of elasticity and Poisson's ratio of CSEB masonry along three directions are determined. The proposed approach is governed by mechanics and not by empirical relationships and provides satisfactory results. © 2023
Multiscale numerical modeling of clay brick masonry under compressive loading
(Springer Science and Business Media Deutschland GmbH, 2024) Honnalli, S.; Vishnu, O.S.; Pavan, G.S.
Masonry is generally comprised of periodic arrangement of masonry unit bonded together with mortar. Masonry is a heterogenous material and exhibits orthotropic behavior. In this study, the elastic-inelastic behavior of brick masonry under compressive loading is predicted using Finite Element Analysis (FEA) based homogenization approach. A three-dimensional repetitive unit cell representing English bond brick masonry is adopted for the homogenization procedure. The proposed approach requires elastic properties, peak compressive and tensile stress, and strain at peak stress values of brick and mortar as the inputs. Material non-linearity in brick and mortar is modeled using concrete damage plasticity model present in ABAQUS software. Using the FEA-based homogenization approach, homogenized stress–strain response of brick masonry subjected to compressive loading (both, normal and parallel to bed joint) and shear loading are obtained. Failure of masonry due to progressive damage development in bricks and mortar joints when subjected to compressive loading is studied. A user-defined material (UMAT) code is developed based on homogenized stress–strain curves. This UMAT can be adopted as constitutive relationship for macro scale modeling of brick masonry using ABAQUS software. The performance of the UMAT is assessed by simulating compression test experiments performed on masonry assemblages found in the literature. The UMAT is found to be satisfactory in predicting the behavior of masonry under compression. © Springer Nature Switzerland AG 2024.