Finite element-based micromechanical modeling of the influence of phase properties on the elastic response of cementitious mortars

Abstract

This study reports the influence of inclusion stiffness and its distribution on the stress distributions in the microstructural phases of different cementitious mortars using microstructure-guided finite element simulations. Randomly generated periodic microstructures with single/multiple inclusion sizes and random spatial distribution, subjected to periodic boundary conditions and a strain-controlled virtual testing regime are chosen for final analysis. Numerical simulations reveal: (i) the differences in locations/magnitudes of stress concentrations as a function of inclusion stiffness and size distribution, and (ii) the sometimes detrimental influence of matrix and interface stiffening/strengthening on the overall composite response, leading to material design strategies when non-conventional inclusions are used in cementitious systems for special properties. The constitutive behavior in the linear elastic regime is extracted based on the predicted dominant principal stresses and strains in the representative area element. Thus, in addition to the microstructural phase stresses, this methodology also provides predictions of the composite elastic modulus, which are observed to be more reliable than those obtained from analytical prediction models.

Microstructure-guided numerical simulations to predict the thermal performance of a hierarchical cement-based composite material

“…While popular because of their simplicity, these techniques are not adequately accurate when large contrast in constituent properties exist, or the volume fractions of the dispersed components are very high [18][19][20]. Computational techniques generally overcome these drawbacks [20][21][22][23][24][25][26].…”

A Peridynamics-Based Micromechanical Modeling Approach for Random Heterogeneous Structural Materials

“…The median inclusion sizes adopted from [38,39] are 20 µm and 600 µm for iron particulates and sand inclusions, respectively. The respective aspect ratios are 12 (iron particulates) and 1(sand) [39,52]. The paste-sand interface is considered 20 µm thick [53][54][55][56].…”

Simulating the Fracture of Notched Mortar Beams through Extended Finite-Element Method and Peridynamics

“…In addition, microencapsulated phase change materials (PCMs) are being proposed for control of thermal cracking in pavements and bridge decks (Fernandes et al 2014), and regulating internal environments in buildings (Hembade et al 2013;Thiele et al 2015), while soft inclusions such as rubber are used for energy absorption (Hernández-Olivares et al 2002), and denser/stiffer aggregates for radiation shielding (Akkurt et al 2006;Makarious et al 1996). The changes in the binder phase and/or incorporation of novel inclusions influence the microstructural stress distribution and consequently the paths/mode of failure of the material (Das et al 2016a). The bulk fracture response of these systems are thus dictated by the microstructure, even though macroscale descriptors are often used as fracture parameters.…”

“…This approach eliminates the shortcomings of typical analytical schemes (Das et al 2015b;Hori and Nemat-Nasser 1993;Mori and Tanaka 1973) and yields a better solution. The modifications in the binder (paste) phase and the changes in inclusion properties can thus be adequately captured (Das et al 2016a). The constitutive response thus generated and the experimentally obtained fracture energy data is used to predict crack propagation in macro-scale cementitious mortar beams.…”