A robust peridynamic computational framework for predicting mechanical properties of porous quasi-brittle materials

Prediction of the macroscopic mechanical properties and damage evolution of cement paste is significant; however, it poses challenges due to the complex multiphase heterogeneity and porosity of the hydration microstructure. This study presents a robust implicit-explicit hybrid computational framework based on the bond-based peridynamics for predicting crack evolution and macroscopic mechanical properties of porous quasi-brittle materials. Specifically, the prototype micro-elastic brittle (PMB) material model is improved by considering an attenuation kernel function and surface effect correction. Subsequently, an efficient implicit-explicit hybrid approach is developed for the solution of the strong form of peridynamic equation of motion. A critical damage index of the global system is specified to switch the solver from implicit to explicit. CEMHYD3D software is employed to generate the microstructure of hydration under uniaxial tension. Systematic simulations of the microstructure explain the influence of several computational strategies on the results, i.e., the approach of boundary enforcement, the geometry of porous microstructure, the loading rate in the explicit stage, and breaking the bonds across the voids or not. The simulations demonstrate that applying the improved bond-based peridynamic solver on hydration microstructures can capture their cracking behavior and macroscopic mechanical properties, e.g., stress–strain curve, peak stress, maximum tensile strain, Young's modulus, and fracture energy release rate. This study also paves the way for peridynamic multiscale modeling of cement-based materials.