Since the properties of thermosetting adhesives for adhesively bonded joints are dependent on the degree of cure of the adhesives, cure monitoring is important. In this work, the dissipation factor which is a function of temperature and viscosity was measured and the relation between the dissipation factor and the degree of cure was investigated using the dielectrometry apparatus by auto balancing Wheatstone bridge and the self sensor of an adhesively bonded joint.
Since the dielectric and piezoelectric properties of adhesively bonded joints were affected by environmental condition and fatigue load, the dissipation factor and piezoelectric constant were measured and related on-line with respect to the environment and load. Also the sensor which uses the adherends of adhesively bonded joint as the electrodes, was devised to measure the degree of cure and the reliability.
