On the fracture behaviour of adhesively bonded CFRP hat-shaped thin-walled beam under axial crushing load: An experimental and modelling study

摘要

Thin-walled beams are widely adopted as the key frontal energy absorption component in automotive body. This work focused on the numerical modelling of a CFRP hat-shaped thin-walled beam under axial-crushing load, which was well validated against testing data as well as experimentally observed fracture behaviour. CFRP hat beam was manufactured with prepreg IM7/8552 through hot-press moulding, and then bonded with a base plate using structural adhesive. The adhesively bonded CFRP beam was loaded under axial crushing to investigate the fracture behaviour in CFRP as well as adhesive layer. The crushing process of CFRP beam was numerically modelled, where the strength-based Chang-Chang failure criterion was adopted to determine the fracture property of CFRP, while Tiebreak was attached in the adhesive and matrix to simulate the interfacial and interlaminar failure. Experimental work revealed that obvious interlaminar failure was observed in CFRP beam, with the outer layers curving outward and inner layers bending inward. Numerical modelling showed good agreement with the experimental data in the aspects of initial peak load and energy absorption. Based on the developed modelling technique, the fracture behaviour in CFRP beam as well as the interfacial failure in adhesive layer and composite matrix can be well predicted and evaluated.