Porosity governs failure in bioconsolidated space bricks

TL;DR

This study investigates how porosity influences fracture behavior in bioconsolidated lunar soil simulant using a novel numerical lattice model to simulate crack evolution and predict failure mechanisms.

Contribution

The paper introduces a new numerical framework that models crack propagation in porous, bioconsolidated lunar soil, accounting for pore effects and variability in material properties.

Findings

Porosity significantly affects crack paths and failure modes.

The model accurately predicts crack nucleation, propagation, and branching.

Statistical parameters encode signatures of crack growth events.

Abstract

Understanding the mechanical response and failure of consolidated extra-terrestrial soils requires analyses of the interactions between propagating cracks the material's inherent pore structure. In this work, we investigate the fracture behaviour of lunar soil simulant consolidated using microbially induced calcite precipitation (MICP). We develop a numerical framework, based on a lattice network with local beam elements, to simulate the nucleation, propagation, branching and merging of multiple cracks within the sample. Our simulations capture the effects of local pores on crack paths as well as provides a means to predict the behaviour of samples with varying global porosity and/or uncertainties in local material stiffness. We identify multiple statistical lattice parameters that encode signatures of single or multiple crack growth events. Our results reveal the complexities involved in the fracture process with porous brittle solids and may easily be adapted to understand failure mechanisms and micro/macro crack evolution in other consolidated structures.