On the influence of Additive Manufacturing defects on the energy absorption capability of a lattice structure

The present paper investigates the influence of AM defects on the energy absorption capability of lattice structure specimens made of carbon nylon. Two typologies of defects are considered through numerical simulations: i) the variation of the diameter of the beam with respect to the nominal value; ii) the presence of lack-of-fusion portions of material within the beams. The defects are randomly disposed in the unit cell and different defect populations are then simulated. Transient nonlinear finite element analyses of the lattice structure subjected to compression tests are performed in the LS-Dyna environment. The numerical model is validated with experimental data collected in a previously published work. Results show that both beam diameter variations and lack-of-fusion defects affect the absorbed energy although with different severities. The increasing degradation of the absorbed energy with the increasing numerosity of the defects confirms the necessity of accounting for these defects when designing latticebased energy absorbers