Effects of transient dynamic loading on the energy absorption capability of composite bolted joints undergoing extended bearing failure

peer-reviewedThe full text of this article will not be available in ULIR until the embargo expires on the 21/05/2022Carbon fibre reinforced polymer (CFRP) materials are widely used in transport aircraft. Crashworthiness requirements demand sufficient energy absorption capacity, especially in the fuselage structure. In a recently-proposed approach, specifically-designed “tension absorber” joints utilize tension loads for energy absorption via progressive bearing failure. For further development of the concept, experimental tests are performed on pin- joints in quasi-isotropic CFRP material, under transient dynamic loading at 3 m/s. Investigated parameters are laminate thickness, stacking sequence and pin diameter, and the results are evaluated using the performance parameters ultimate bearing strength, mean crush stress and mass-specific energy absorption. A strong relation between the ratio of pin diameter to laminate thickness, D/t, and the performance parameters is found. Compared to previous results for quasi-static loading, the ultimate bearing strength is increased whereas the mean crush stress and mass-specific energy absorption are reduced. Digital image correlation and computed tomography analysis reveals the mechanisms behind the observed trends. The results provide a basis for further optimization of energy-absorbing joints and validation of finite element models