Energy absorption analysis on variable thickness CFRP/aluminum hybrid square tubes under oblique loading

The variable thickness hybrid square (VTHS) tubes are used to improve the energy absorption under oblique loading and the relative advantages compared with the uniform thickness hybrid square (UTHS) tubes are studied. First, a oblique compression test and finite element model were established to analyze the deformation mode and load-displacement curve of VTHS tube. Then, the parameter studies of VTHS and UTHS tubes were carried out. The results show that increasing thickness leads the structures to be prone to global bending mode, and the energy absorption performance is reduced. Compared with UTHS, VTHS tubes can increase the specific energy absorption when the progressive crushing mode occurred at the same loading angle. Meanwhile, the progressive crushing deformation with excellent energy absorption performance can still appear when the loading angle exceeds 30 degrees. Finally, a unified equation for the relationship between the dimensionless mean crushing force and the loading angle was proposed.