Enhanced Energy Absorption Performance of Liquid Nanofoam-Filled Thin-Walled Tubes under Dynamic Impact

Abstract

Thin-walled structures have been widely used among other energy absorbing structures in automotive, aerospace and other industries, due to their high energy absorption capacity and light weight. In some cases, these structural components were filled with metallic foams to further improve their energy absorption performance and capacity. This may lead to an increase in the structural component weight. In this study, a highly compressible liquid filler, i.e. liquid nanofoam (LN), has been introduced into the thin-walled tubes. We have characterized the mechanical response of these LN-filled tubes (LNFTs) by using quasi-static compression tests and dynamic impacts. The quasi-static compression tests are conducted by an MTS system. Results show that the energy absorption capacity of LNFTs is 45% higher than that of identical empty tubes. The dynamic behavior of LNFTs is characterized by using a gas gun apparatus at impact speed of 6.7 m/s. It is found that the energy absorption capacity of LNFTs is 76% higher than that of identical empty tubes. Importantly, by increasing the strain rate from quasi-static condition (10−2 s−1) to intermediate range (102 s−1), the energy absorption capacity of LNFTs is increased by 54% without increasing the working pressure of the system. The strain rate sensitive behavior of LNFTs suggests that LNFTs can be used as advanced energy absorber whose impact mitigation capability is adaptive to the impact energy levels. These findings warrant future considerations of these new liquid nanofoam filled thin-walled structures for vehicle crashworthiness and infrastructure protection.