Tests of deck-to-hull adhesive Joints in GFRP boats

A test program has been designed for the testing of several deck-to-hull adhesive joints in order to assess the strength and performance while in-service conditions, and the dynamic behavior under cyclic loads of the adhesive bonding in the presence of a debonded area. The tests have also been used for benchmarking of several different adhesive systems as potential candidates to be used in these joints. The fundamental aim has been to reproduce the in-service dynamic loads acting on the deck-to-hull adhesive joint in a suitable test specimen. In the presence of a pre-existing debonding, loads on the adhesive correspond to a mixed modes (modes I and II) fracture situation. A specific load fixture has been developed and used for the testing of the specimens in the mixed mode. Material and manufacturing process are representative of the actual procedure in the yacht industry. The joint design is not assumed to be the optimum for this application, but it has been chosen for the sake of simplicity during testing. Quasi-static tests for the determination of the initial and residual strengths have shown that we cannot point out only one adhesive system as the ideal candidate in all the aspects. All of them have strong and weak features, and the final selection has to be done within the scope of the final performance needed for a certain application. Fatigue tests have not shown specimen failure during the number of cycles selected. Strengths of the damaged specimens have shown in most cases a negligible reduction respect to the undamaged initial situation. (C) 2006 Elsevier Ltd. All rights reserved.