The effect of quartz nano-particles on the damage monitoring of adhesive joint at cryogenic temperature

Abstract

Recently, a piezoelectric method using piezoelectric characteristics of epoxy adhesives has been successfully developed for the adhesive joints, which can monitor continuously the damage of adhesively bonded structures without producing any defect induced by inserting a sensor. However, due to low piezoelectric properties of epoxy adhesives, the detection of micro crack was impossible. At the cryogenic temperature, the detection of micro crack is important to estimate the fatigue life because the polymeric adhesives become very brittle. Therefore, in this work, the epoxy adhesive was modified by quartz nano-particles which have much higher piezoelectric properties than the epoxy adhesives. To investigate the effects of quartz nano-particles, the static and dynamic tests of the tubular adhesive joints were performed to compare the joint strength and sensitivity of damage monitoring performance. From the experiment result, it was found that the quartz nano-particles not only improved the joint strength but also increased the sensitivity of damage monitoring performance at cryogenic temperature.