Experimental and FE analyses of the crushing and bending behaviors of GMT and hybrid-formed Al-GMT structures

This paper describes the experimental behaviors and FEA of GMT and hybrid Al-GMT structures under bending and axial crushing loadings. Previous investigations have revealed that GMT profiles may provide promising energy absorption and weight savings in automotive body structures if structural integrity issues are solved by FRP–metal hybrid. Such an FRP–metal hybrid can be cost-efficiently manufactured by a single-stage hybrid forming process that combines sheet metal, FRP forming, and adhesive bonding between them simultaneously. A reliable FE model capable of predicting the complex material architecture, as well as the failure behavior of the pure GMT and the bonded Al-GMT hybrid profiles, is thus required to realize the full potential of the new material combination. In this work, a prospective methodology is proposed to numerically predict the behavior of hybrid structures. For each material, a separate material model of LS-DYNA was proposed and investigated. As a result, the built FE model was validated by experiments on both three-point bending and axial crash tests using two different hat profiles. The crushing morphologies and fracture mechanisms are compared and discussed.