Evaluating the Integrity of Adhesive Bonds by the Measurement of Acoustic Properties under Stresses

Evaluating the integrity of adhesive bonds by the measurement of acoustic properties under stresses

“…As a result, the time-of-flight was observed to be temperature dependent in adhesively bonded test samples. The contributing factors for such changes in the adhesively bonded samples are due to two important factors, namely [2]: i) that the materials associated with the bondline region themselves have a definite temperature coefficient of velocity and ii) that the stresses are created in the adherend-adhesive interface due to the differences in the temperature coefficients of the linear expansion of these two materials.…”

“…Stage 1: Increase in shear stress will cause an increase in the time-of-flight [2,4]. Application of shear load thus increases the time-of-flight.…”

“…The bridgefixture was fmnly mounted to the larger steel plate in order to maintain consistent and stable distances between the two probes during successive tests. Acoustical properties are temperature sensitive [2] and therefore, an oven consisting of an aluminum shell, was used to enclose the test sample during the measurements. The use of an oven enabled control and maintenance of temperature to better than 0.0 10C.…”

“…Simultaneous acquisitions of mechanical data, temperature and acoustic data were carried out through a computer controlled data acquisition system [2].…”