High strain-rate properties of hybrid aluminium and polyurethane foams

An increasing interest in lightweight metallic foams for automotive, aerospace, and other applications has been observed in recent years. This is mainly due to the weight reduction that can be achieved using foams and for their mechanical energy absorption and acoustic damping capabilities. An accurate knowledge of the mechanical behaviour of these materials, especially under dynamic loadings, is thus necessary. Unfortunately, metal foams and in general “soft” materials exhibit a series of peculiarities that make difficult the adoption of standard testing techniques for their high strain-rate characterization. This paper presents the high strain-rate characterization of two types of open-cell aluminium foams using an innovative apparatus, where high strain-rate tests of metal foams or other soft materials can be performed by exploiting the operating principle of the Hopkinson bar methods. Using the pre-stress method to generate directly a long compression pulse (compared with traditional SHPB), a displacement of about 20 mm can be applied to the specimen with a single propagating wave, suitable for evaluating the whole stress-strain curve of medium-sized cell foams. In detail first material is a traditional open-cell aluminium foam while the second one is a hybrid foam, where a coating of nano-crystalline nickel is deposited on open-cell aluminium foam. The experimental data presented proves the effectiveness in the energy absorption capabilities of the second foam type due to the nano-crystal nickel properties and lead to the development of a new innovative and advanced material classes: hybrid polyurethane-nickel foams, where a coating of nano-crystalline nickel is deposited on cheap open-cell polyurethane foam.

PERONI Marco;  JUNG Anne;  LARCHER Martin;  SOLOMOS George; 

2016-11-22

Politecnico di Torino

JRC100933

https://publications.jrc.ec.europa.eu/repository/handle/JRC100933,