Abstract
Fatigue tests were conducted on scarf adhesive joints (SAJs) with composite substrates at room temperature (RT) and 50 °C. The adhesive layer was modified with Al2O3-nanoparticles. Dynamic parameters such as damping factor, storage modulus, dissipated energy and potential energy (Up) were measured from the stress–strain hysteresis loops of the SAJs with the aim of knowing which ones are best for early prediction of joint collapse. Incorporation of Al2O3-nanoparticles into the adhesive layer improves the fatigue strength by about 4.8 and 24.5% at RT and 50 °C respectively. The glass transition temperature was improved by 8.3% and thus, at 50 °C the fatigue strength of the Al2O3-SAJs was decreased by 5.4% in return of 20.3% for the NE-SAJs. The variation of the Up with fatigue life is more pronounced compared to the other dynamic parameters and thus, can be modeled to monitor the integrity of the joint and preventing their catastrophic failure.