The size effect in quasi-brittle materials: Experimental and numerical analysis

Abstract

The size effect in structures is responsible for the materials apparent properties variations as function of size. Different methodologies are proposed in the literature to address this phenomenon; however, there is still no consensus on how to specifically deal with this. For instance, if the material investigated were a quasi-brittle material, it would present a fissures development in different scales during the damaging process. In the present work, an experimental study applying uniaxial tension over expanded polystyrene specimens of different sizes is proposed. The acoustic emission events occurring during the tests were also recorded. A tailored version of a lattice discrete element method was used to simulate the tests. This numerical approach take into account several phenomena related with the damage process in quasi-brittle materials, such as the localization effect, the fractal dimension nature of the region over which the damage evolves; the collaborative effect between cluster of fissures and the avalanche effect during the damage process. It is important to mention that these characteristics are associated with the correct simulation of the acoustic emission registry. The obtained experimental and simulated results were in great agreement and clearly showed a size effect, despite the narrow range of dimension explored. The size effect evaluated during the simulations, in terms of the dissipated energy, is shown to be in agreement to the known fractal theory proposed by Alberto Carpinteri and coworkers. Moreover, results in terms of acoustic emission are preliminarily explored to determine the correlation between the acoustic emission events and the fracture mode that governs the source of these events. Finally, some conclusions related to the size effect captured during the tests and the possibilities for simulations of the fracturing process in quasi-brittle materials provided by the numerical method are point out.

A review of continuum damage and plasticity in concrete: Part II – Numerical framework

“…Static loading (Abu Al-Rub and Ahmed et al, 2020Ahmed et al, , 2021aAhmed et al, , 2021bBi et al, 2009;Bobi nski and Tejchman, 2016;Cervera et al, 2018;Cicekli et al, 2007;Contrafatto and Cuomo, 2006;Desmorat et al, 2007a;Desmorat and Gatuingt, 2008;Grassl and Jira ´sek, 2006;He et al, 2015;Mazars et al, 2015;Sa ´nchez et al, 2012) Dynamic loading (Burlion et al, 2000;Cervera et al, 1996;Chen, 1996Chen, , 1999Grassl et al, 2011;Herv e-Secourgeon et al, 2005;Huang et al, 2005;Ju, 1989;Kotronis et al, 2003;Lu and Xu, 2004;Mazars et al, 2015;Mazars and Grange, 2017;Omidi and Lotfi, 2013;Pereira et al, 2016;Ragueneau and Gatuingt, 2003;Ren et al, 2015) Size effect (Alam et al, 2020;Ba<Zant and Kazemi, 1990;Ba zant and Pang, 2007;Colpo et al, 2016;de Borst and Guti errez, 1999;Duan et al, 2006;2007;Havla ´sek et al, 2016;Karihaloo, 1999;Karihaloo et al, 2003;Krayani et al, 2007;…”

“…¼ 50, R ¼ 36.25, W ¼ 100 9) D ¼ 100, R ¼ 72.5, W ¼ 100 10) D ¼ 200, R ¼ 145, W ¼ 100 11) D ¼ 400, R ¼ 290, W ¼ 100 12) D ¼ 800, R ¼ 580, W ¼ 100 13) D ¼ 1600, R ¼ 1160, W ¼ 100(Colpo et al, 2016) 1) D ¼ 90, R ¼ 65.25, W ¼ 10 2) D ¼ 150, R ¼ 108.75, W ¼ 10…”

A numerical chemo-micromechanical damage model of sulfate attack in cementitious materials

“…As a new micromechanical analysis method in this work, the discrete element method (DEM) can be adopted to analyze the damage of cementitious materials at the micro-scale (Colpo et al., 2017; Jin and Arson, 2018; Pathirage et al., 2019; Suchorzewski et al., 2018; Zhou et al., 2016, 2017). In addition, it was adopted to examine the failure of cementitious materials under the internal SA (Liu et al., 2019a).…”

A Novel Implementation of the LDEM in the Ansys LS-DYNA Finite Element Code

“…In the present research work, the Lattice Discrete Element Method (LDEM) originally proposed by Riera [29] is employed to evaluate the fracture behaviour of sandwich panels subjected to bending. Note that the novelty of the paper is represented by the hybrid model proposed (named LDEM-DYNA model), obtained by using Ansys LS-DYNA finite element code [30] in conjunction with the LDEM [31][32][33][34][35][36][37][38][39][40][41].…”