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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°. Finally, a unified equation for the relationship between the dimensionless mean crushing force and the loading angle was proposed. [ABSTRACT FROM AUTHOR]

This paper aims to explore the off-center low-velocity impact response and damage characteristics of carbon fiber reinforced aluminum laminate (CARALL). Progressive damage finite element models of CARALL considering the stiffness degradation and damage evolution of carbon fiber reinforced plastic (CFRP) were established using a user subroutine and verified by off-center impact tests with different impact energies. The motion propagation, damage, and spatial distribution of dynamic responses of CARALL impacted in different locations are studied. The results indicate that increase in impact distance from center dissipates more energy due to the more severe damage and failure of CFRP, while the off-center impact have a negative effect on the plastic energy absorption of metal compared with center impact. A quantitative expression is proposed to describe the spatial distribution of the maximum transverse displacement. [ABSTRACT FROM AUTHOR]

The CFRP/Al hybrid multi-cell tubes have an excellent energy absorption performance under axial crushing loading. This paper creatively proposes a theoretical analysis model to predict the mean crushing force of hybrid multi-cell tubes and studies the effects of the number of cells on the deformation mode of CFRP/Al hybrid multi-cell tubes. The accuracy of theoretical model is verified by experimental results. Theoretical analysis results show that the bending energy and membrane energy of metal, and friction energy of CFRP are the major energy absorption mechanisms for hybrid multi-cell tubes. The decreases of half-wave length and the increase of membrane force is the main reason that the hybrid multi-cell tube is more prone to deformed in mixed mode than the hybrid square tubes. The proposed theoretical model can quickly predict the mean crushing force and energy dissipated by each mechanism when the CFRP and metal's material and geometric parameters are given. • An analytical model of the hybrid multi-cell tubes with mixed mode is newly proposed. • Deformation mode and axial crushing response are anayzed by experiments. • The major energy dissipation mechanisms for hybrid multi-cell tubes is explicitly derived. • Increase of the membrane force is the main reason for emergence of the mixed mode. [ABSTRACT FROM AUTHOR]

This paper aims at studying the bending collapse behavior of the thin-walled twelve right-angle section (TTRS) beams filled with aluminum foam. This paper presents the theoretical bending characteristics of the TTRS-typed aluminum foam around two axes. Considering the contribution degree of thin-walled beam and aluminum foam in different angle range, the expressions of the bending moments are derived. The accuracy of the theoretical calculations are validated by performing 14 groups finite element simulations respectively including three kinds of aluminum foams with certain scope of plateau stress (1–12.5 MPa) and corresponding density (0.2–0.52 g/cm 3 ). The results show that the bending collapse theory proposed in this paper can reflect the mechanical properties of the TTRS beams filled with aluminum foam accurately, and the moment–rotation curves calculated by theory are in good agreement with simulation results. [ABSTRACT FROM AUTHOR]

Metal/composite hybrid square tubes that combine the advantages of low-density of composite with low-cost of metal provide a potential energy absorption device for automobiles. The axial crushing performance of CFRP/aluminum hybrid square tubes wrapped with single angle-ply and antisymmetric angle-ply was studied by experimental and numerical methods. Results show that for tubes wrapped with single angle-ply [0] 4 or [45] 4 , crack propagation occurred and the CFRP separated from aluminum, which resulted in worse energy absorption capacity than pure aluminum tube. A stable symmetric deformation was observed in hybrid square tubes wrapped with antisymmetric angle-ply. The specific energy absorption (SEA) for those tubes was improved 11% and they showed better energy absorption performance compared to pure aluminum tube. Then, the effect of thickness of tubes, including hybrid square tubes with identical aluminum and hybrid square tubes with identical mass, on the energy absorption capacity was further investigated by simulation. It was found that only when the number of CFRP layer reaches a certain value, hybrid square tubes perform better than pure aluminum tube with identical mass in energy absorption. Moreover, influence of mass of the tube, and substituting aluminum alloy with CFRP on the energy absorption of hybrid square tubes with identical aluminum and different number of CFRP layers was studied. • Axial crushing performance of hybrid square tubes with single and antisymmetric angle-ply was experimentally studied. • The finite element model of hybrid square tubes was established and verified by the experimental data. • Effect of thickness of tubes with identical aluminum and that with identical mass on energy absorption was investigated. • Mass of the tube and replacing aluminum alloy by CFRP was considered in the energy absorption of hybrid square tubes. [ABSTRACT FROM AUTHOR]

Variable thickness hybrid square (VTHS) tubes which had variable thickness of CFRP to achieve the variation of axial crushing performance are proposed. To study the crushing characteristics and relative advantages of the VTHS, pure aluminum tube, uniform hybrid square tube and VTHS were manufactured firstly, and their axial crushing tests were conducted. Experimental results showed that, compared with uniform hybrid square tube, VTHS had lower initial peak crushing force. Finite element models were established and verified to explore the effect of parameters of the tubes on axial crushing performance further. Numerical results showed that the crushing force can be controlled by varying the thickness of CFRP. Compared with uniform thickness hybrid square tube, VTHS had an improvement of 24.5% in specific energy absorption and increase was greater for the VTHS with thinner metal. Effects of the mean thickness, thickness difference, and number of segments of CFRP on the energy absorption performance were studied. Finally, a theoretical model to predict the mean crushing force was proposed and its accuracy was verified by tests. Results demonstrate that theory can be used to obtain the mean crushing force of each segment of VTHS accurately. [ABSTRACT FROM AUTHOR]