Compressive and Energy Absorption Behavior of Multilayered Foam Filled Tubes

This article investigates the compressive and energy absorption characteristic of metallic foams and functionally graded foam (FGF) filled tubes containing single-, double-, and triple-layered foams. Closed-cell A356 alloy and pure zinc foams are fabricated by the casting method. The results indicate the preparation of A356 foam with larger bubbles and thinner cell walls and, thereby, lower density and compressive strength compared to the zinc foam. The metallic foams show partially brittle behavior associated with cell walls bending and tearing. The double-layered structures exhibit multiple compression behavior and two distinct plateau regions. The presence of high density zinc foam leads to decreasing the specific energy absorption (SEA) of graded structures. However, the compressive deformation and total energy absorption are significantly affected by the zinc foam. The crash performance of multilayered structures can be controlled by varying the number and material of layers at constant geometric features. The single-layered A356 and double-layered A356-Zn and Zn-A356 structures are considered as the best lightweight crashworthy structures with a combination of high SEA (15.3, 7.7, and 7.3 J/g) and low plateau force (10, 13, and 12 kN). Also, an asymptotic hardening model is developed for the porous metals based on the experimental results.