Effect of internal defects on the compression behavior of 3D printed lattice structures

This study investigates the influence of internal pore defects on the quasi-static compressive behavior and mechanical response of metal lattice structures fabricated using selective laser melting (SLM) additive manufacturing. The findings aim to provide a reference for evaluating the mechanical properties of new ship protection structures created through SLM additive manufacturing.

Quasi-static compression tests and simulation calculations were conducted on 3D-printed lattice structures with porous defects. The Gurson−Tvergaard−Needleman (GTN) porous metal plasticity model, which accounts for internal pores, was employed for the simulation calculations. The damage parameters of the GTN model were calibrated using the Central Composite Design (CCD) and Response Surface Methodology (RSM), with experimental validation.

The results show that under quasi-static compression, micro-voids within 3D-printed lattice structures tend to coalesce in stress-concentrated regions, forming larger voids. This leads to significant reductions in structural strength, load-bearing capacity, and energy absorption efficiency. The computational model, which incorporates pore defects, can predict the mechanical failure behavior and energy absorption characteristics of 3D-printed lattice architectures with high accuracy, showing a deviation of only 0.25% from the experimental energy absorption results.

The research findings provide a reference for evaluating the mechanical properties of new ship protection structures made through SLM additive manufacturing. The model that incorporates pore defects effectively predicts the energy absorption capability of lattice structures with defects, and the compression performance of the structures significantly decreases as porosity increases.