Performance and failure mechanics of carbon fiber reinforced polymer composite T-joint in quasi-static loading for automobile structures

This paper presents an analytical, finite element and experimental study on the mechanical behavior of thermoplastic carbon fiber reinforced polymer (CFRP) T-joint subjected to out-of-plane bending and bending-torsion coupling. The relationship between failure mode and load-displacement curve was analyzed. The analytical, finite element and experimental results were compared. In bending test, the stiffness discrepancies in analytical and finite element model compared to that in the experiment are 4.7% and 0.5%, respectively. In bending-torsion test, the stiffness discrepancies in analytical and finite element model compared to that in the experiment are 6.9% and 9.6%, respectively. The results in the experiment show that the progressive damage of CFRP laminate causes the damping of transverse bending stiffness of the T-joint. The T-joint begins to fail when the force reaches 2 047 N. The failure results include matrix cracking, matrix/fiber deboning of transverse fibers, delimitation and fiber breakage leading to transverse rupture.