Experimental and numerical investigation on fatigue damage in micro-lattice materials by Digital Volume Correlation and μCT-based finite element models

This work addresses the fatigue behaviour of two strut-based topologies of micro-lattice materials, focusing in particular on the damage evolution throughout the fatigue life. An experimental campaign is performed on micro-lattice specimens tested in fatigue with different stress ratio (R = 0, R = −1 and R = 10). A methodological approach for metal foams is adopted to analyse the experimental tests and to characterize the fatigue damage evolution. To validate this approach the Digital Volume Correlation technique is applied on two in-situ experimental fatigue tests conducted inside a Micro-Computed Tomography scanner. An analysis based on a finite element model of the as-manufactured geometry and the application of a suitable multi-axial fatigue criterion to evaluate the local stress field shows good results in predicting the fatigue failure location. • Fatigue damage evolution in lattice materials can be summarized by damage maps. • Damage maps show a significant effect of the stress ratio on the damage evolution. • In-situ Digital Volume Correlation (DVC) tests confirm the damage maps. • Failure location predicted by a fatigue model is in good agreement with DVC results.