Computational homogenization of fatigue in additively manufactured microlattice structures

A novel computational approach to predicting fatigue crack initiation life in additively manufactured microlattice structures is proposed based on a recently developed microplasticity-based constitutive theory. The key idea is to use the concept of (micro)plastic dissipation as the driving factor to model fatigue degradation in additively manufactured metallic microlattice. An ad-hoc curve-fitting procedure is proposed to calibrate the introduced material constitutive parameters efficiently. The well-calibrated model is employed to obtain fatigue life predictions for microlattices through a diverse set of RVE-based finite element fatigue simulations. The model's predictive capabilities are verified by comparing the simulation results with experimental fatigue data reported in the literature. The overall approach constitutes a unified setting for fatigue life prediction of additively manufactured microlattice structures ranging from low- to high-cycle regimes. It is also shown that the model can be applied to technologically relevant microlattices with mathematically-created complex microstructure topologies.

Automated summary

A novel computational approach for predicting fatigue crack initiation life in additively manufactured microlattice structures is proposed. The approach uses the concept of (micro)plastic dissipation as the driving factor for modeling fatigue degradation and employs a curve-fitting procedure to calibrate the material constitutive parameters. The model's predictive capabilities are verified by comparing the simulation results with experimental fatigue data, and it is shown to be applicable to technologically relevant microlattices with complex microstructure topologies.