RTM COMPOSITE LUGS FOR HIGH LOAD TRANSFER APPLICATIONS

摘要

This paper presents the work performed on composite RTM lugs designed for aerospace applications. The objective was to get information on stiffness, strength and failure mode of both the lug and the joint between the lug and main structure. The main design driver after structural requirements was the use of cost effective manufacturing methods. The selected concept was designed, manufactured and structurally tested. The analyses were performed using finite element method. A steel pin together with contact definition was modelled to apply the loading to the lug. The test lugs were manufactured with the resin transfer moulding (RTM) technique. The materials used were carbon fibre fabric 2 and epoxy resin RTM . The surrounding structure was represented by face sheets, a spar and a rib behind the lug. The test specimens were loaded with straight tension loading. The lug strength exceeded the expected value because of conservative design methods. Owever, the bonded joint between the lug and the surrounding structure failed at much lower load than expected. Based on the work done it can be concluded that 1) the proposed lug geometry is a feasible solution for high load transfer applications, 2) the peel strength of the adhesive in the secondary bonded lug plays an important role in the ultimate strength of the lug and 3) the bonded joint with the lug and the surrounding structure can be repaired and original strength is possible to retain.