USING ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY FOR HEALTH MONITORING OF COMPOSITE-COMPOSITE AND ALUMINUM-COMPOSITE BONDS

摘要

Electrochemical impedance spectroscopy (EIS) measurements were taken of CFRP and GFRP lap shear specimens during exposure to 95% relative humidity at 50℃, 70℃, and 90℃. Periodically, the lap shear specimens were pulled to determine the degradation of bond strength during hygrothermal aging. The low-frequency impedance correlated well with bond strength of the lap shear specimens exposed to high humidity. The changes to the impedance spectra and the decrease to the adhesive strength were both caused by moisture absorption by the adhesive. Comparison of the rate of impedance changes and strength degradation suggest that moisture absorption was the limiting factor in the deterioration of bond properties.