Mechanical behavior of additively manufactured functionally graded porous structures

Functionally graded porous structures have been extensively developed in the past decades, which also makes graded foams popular due to their potential for energy absorption. However, experimental investigation on graded foams remains limited. Therefore this study aims to fill this gap by investigating the compressive behavior of graded foams and establishing predictive models. Firstly, uniform and graded foams are both additively manufactured. Compared to uniform foams, graded foams show similar behaviors in elastic and densification stages, while they possess a hardening plateau stage rather than a constant one. In other words, graded foams exhibit successive plateau stresses of their component layers. This indicates that the graded-foam property can be modeled using the mechanical properties of uniform-foam layers. From experimental results, we propose an elastic, plastic-hardening model for graded foams. The proposed model further allows tailoring the mechanical properties of graded foams for various engineering applications without conducting experimental studies.