Low-velocity impact performance of composite-aluminum tubes prepared by mesoscopic hybridization

Novel circular hybrid structures with overlapped carbon-fiber-reinforced plastic (CFRP), glass-fiber-reinforced plastic (GFRP) and/or aluminum layers were fabricated. Such structures were hybridized at the mesoscopic scale, generating multiple CFRP-GFRP or composite-aluminum interfaces. Also, aluminum foam was utilized as inner filler to further enhance the energy absorption of the thin-walled structures. The interactive effects on crashworthiness among different materials were explored by axial drop-weight impact testing. The experimental results showed a progressive failure process of all CFRP/GFRP and composite/aluminum hybrid tubes. The mean crushing force (MCF) of empty CFRP/GFRP hybrid structures were significantly improved by more than 20% when compared to pristine CFRP tube. On the other hand, the composite/aluminum hybrid design effectively reduced the peak crushing force (PCF) and improved the crushing force efficiency (CFE). However, the specific energy absorption (SEA) was decreased by about 10% owing to the moderate strength-to-weight ratio of inserted aluminum sheet. Compared to empty tubes, the filling of aluminum foam significantly enhanced MCF by more than 10%, while declining SEA due to the low weight efficiency of aluminum foam. In sum, the proposed hybrid design maximized some aspects of crashworthy performance at a low cost, thereby promising for the future design of practical light-weight energy absorbers.

Automated summary

Novel circular hybrid structures were fabricated with overlapping CFRP, GFRP, and aluminum layers, showing improved crushing force and peak crushing force reduction in crashworthiness testing. The use of aluminum foam as inner filler further enhanced energy absorption, although there was a slight decrease in specific energy absorption due to the weight efficiency of the aluminum foam. This hybrid design offers promise for the future design of practical lightweight energy absorbers.