Experimental and numerical studies on the bending collapse of multi-cell Aluminum/CFRP hybrid tubes

Wrapping the structures with composites and adopting multi-cell sections are two typical methods to improve the crashworthiness of thin-walled beams. However, the effects of combining these two methods on crashworthiness are not clear. This paper aims to investigate the bending collapse and crashworthiness of the multi-cell aluminum/carbon fiber reinforced plastic (Al/CFRP) hybrid tubes under quasi-static and dynamic loading. Three-point bending tests are firstly conducted for the CFRP, Al and Al/CFRP square tubes with single or multi cell sections. The deformation characteristics and crushing force responses of the tubes are analyzed, and the energy absorption performances are evaluated. The bending resistance of the Al tubes is increased by up to 41% attributed to the CFRP enhancement. The non-linear finite element software ABAQUS/Explicit is then employed to simulate the tests and help analyze the deformation mechanisms. Parametric studies are performed to investigate the influence of the Al wall thickness, the number of CFRP plies, loading velocity, partial wrapping and sectional shape on the crashworthiness of Al/CFRP tubes. Results show that the Al wall thickness, partial wrapping, and sectional shape have a significant influence on the deformation pattern and force response of Al/CFRP tubes, while the number of CFRP plies and the loading velocity have a relatively small influence. The specific energy absorption of Al/CFRP tubes can be increased by 11% by introducing partial CFRP wrapping, and in all cases, the multi-cell Al/CFRP tubes outperform the single-cell counterparts in crashworthiness performances.