Factors affecting the procedure for testing cavitation erosion of GFRP composites using an ultrasonic transducer

In many marine applications, glass fibre reinforced polymer (GFRP) composites are exposed to adverse environmental effects including cavitation. Prolonged exposure to cavitation can damage GFRP composite surfaces that would eventually require repairing or replacing marine device components. This study initially investigates the deterioration of GFRP composite and its constituent materials (i.e., epoxy and glass) by cavitation erosion. The cavitation cloud is produced by an ultrasonic transducer, and cavitation erosion tests adhered to ASTM G32-16 standard. It is shown that the erosion process of GFRP composite has characteristics of both epoxy and glass. The second part of this study investigates the effect of several parameters associated with the experimental setup, testing procedure and material properties on ultrasonic cavitation erosion of GFRP composite. These parameters include gas content in testing liquid, type of specimen support, specimen water absorption, acoustic impedance, and tensile strength. It is reported that specimen edge treatment influenced water absorption, specimen preconditioning was important for accurate recording of erosion damage accumulation, acoustic impedance and tensile strength were directly correlated with erosion damage, while the cavitation erosion process of GFRP composite was mostly insensitive to gas content in testing liquid but was significantly affected by the type of specimen support.