Hybrid Joint Between Steel Deck and Fiberglass Superstructure

Abstract

In semi-displacement vessels, the reinforced fiberglass composite superstructure, or FRP, is one of the best construction options due to its low weight, shape, and surface finish. A problem with the FRP composite material lies in the joint with the steel hull due to the lack of adherence in the joint between the deck and the superstructure’s FRP panels. This research presents a solution for hybrid joints between the deck and the FRP superstructure using a steel tubular structure and laminates with Isoftalic Resin. The design shear stress for the lamination of this hybrid joint has been considered to be 4.55 MPa, according to the recommendation of Lloyd’s Register. The analysis initially makes an estimate of the reactions at the hybrid joint based on a 36.80-m ship and then performs a critical layer analysis with the finite elements method. This is followed by an analysis of possible hybrid joints to find the best option for a construction that fulfills design stress. The final hybrid joint presents better results and consists of ASTM B53 steel tubes, Sch40, and uses vertical tubes 2 in. in diameter and 60 cm in height as well as two longitudinal tubes of 1 in. in diameter at 30 cm and 60 cm from the deck, respectively.