Joints and Adhesives

In many RPs, the most convenient joint will be a bonded type (possibly produced during the lay-up process), and the geometry is therefore very influential. The weakest joints are those where failure is limited by inter-laminar failure of the adherend, or peel of the adhesive. Next strongest are those where the load is limited by the shear strength of the adhesive. The strongest designs will fail outside the joint area, at a load equivalent to the strength of the adherend. 

Selection of adhesives depends on many requirements, particularly the nature of the materials to be bonded, the function of the bond. 

One-piece RP components replace multiple parts previously made both from RPs and from metals or other materials including unreinforced plastics. The motivations for the design and the challenges for fabricating 

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Laminates were manufactured mainly by Neste subsidiary Plastilon Oy. The laminates A300 WR, A300 UDl and A300 UD2 were manufactured by the Helsinki University of Technology, Laboratory of Lightweight Structures (HUT/LLS). Adhesively bonded joints and specimens for the mechanical characterisation of the adhesives were made by HUT/LLS. Laminated joints were made by Neste and HUT/LLS. All laminates, laminated joints, and adhesives were cured at room temperature for 24 hours minimum and then postcured according to the procedures given in Table 3. 

There are a number of useful publications which discuss structural joints and adhesives in detail [13-16]. 

Jones, Peter, Fasteners, Joints and Adhesives A Guide to Engineering Solid Constmctions, Englewood Cliffs, NJ, Pientice-Hall, 1983. 

This test is very important in metal bonding and aerospace industries, where it is used not only to measure the adhesion and mechanical resistance of the joints and adhesives, but also to test the efficiency of the preparation of surfaces before bonding. 

Bonded hox spars were used in the wings together with laminated spruce booms. To build up the rear spars, sections were joined using scarf joints and adhesive. 

Abstract This chapter constitutes one of the very few reviews in the existing literature on shoe bonding, and it gives an updated overview of the upper to sole bonding by means of adhesives. The surface preparation of rubber soles and both the formulations of polyurethane and polychloroprene adhesives are described in more detail. The preparation of adhesive joints and adhesion tests are also revised. Finally, the most recent development and technology in shoe bonding is described. 

Pie2oelectric materials are used in many different types of sensing—actuating devices. A few appHcations include printing, monitoring of performance behavior of adhesive joints, and intelligent processing. 

Bond and Adhesion (ASTM D1191). This test, designed for use on crack and joint sealers, is used primarily to determine whether a jointing material possesses an arbitrary amount of bonding strength at low temperatures where pordand cement concrete is being used. 

Solders should flow promptly and smoothly over the surfaces of the parts to be joined. This property depends on the surface tension, viscosity, and adhesive properties of the molten solder. Finally, the color of a solder should match that of the metal employed, and its physical properties should be at least as good as those of the metal, in order for the joint not to be a source of weakness (150). 

Glass-reinforced polyester is the most widely used reinforced-resin system. A wide choice of polyester resins is available. The bisphenol resins resist strong acids as well as alkahne solutions. The size range is 2 through 12 in the temperature range is shown in Table 10-17. Diameters are not standardized. Adhesive-cemented socket joints and hand-lay-up reinforced butt joints are used. For the latter, reinforcement consists of layers of glass cloth saturated with adhesive cement. 

In addition to epoxy-phenolic adhesives three-part epoxy-phenolic-nitrile rubber systems are used in metal-metal edge joints and honeycomb constructions [208], These add toughness not available in most EP systems and improve peel strengths. When used on honeycomb, the NR-P is normally applied to the aluminum skin and the EP to the honeycomb for assembly. Service temperature limitations are those imposed by the NR-P part. 

Thrall, E.W. Jr., Failures in adhesively bonded structures. AGARD Lecture Series No. 12. Bonded Joints and Preparation for Bonding. North Atlantic Treaty Organization Advisory Group for Aerospace Research and Development, London, 1979. 

Soesatyo B, Blicblau AS, Siores E. Effects of microwave curing carbon doped epoxy adhesive-polycarbonate joints, nternational Journal of Adhesion and Adhesives. 2000 20(6) 489-95. 

Adhesives and sealers can be an important part of a total corrosion protection system. Structural bonding procedures and adhesives for aluminum, polymer composites, and titanium are well established in the aerospace industry. Structural bonding of steel is gaining increasing prominence in the appliance and automotive industries. The durability of adhesive bonds has been discussed by a number of authors (see, e.g., 85). The effects of aggressive environments on adhesive bonds are of particular concern. Minford ( ) has presented a comparative evaluation of aluminum joints in salt water exposure Smith ( ) has discussed steel-epoxy bond endurance under hydrothermal stress Drain et al. (8 ) and Dodiuk et al. (8 ) have presented results on the effects of water on performance of various adhesive/substrate combinations. In this volume, the durability of adhesive bonds in the presence of water and in corrosive environments is discussed by Matienzo et al., Gosselin, and Holubka et al. The effects of aggressive environments on adhesively bonded steel structures have a number of features in common with their effects on coated steel, but the mechanical requirements placed on adhesive bonds add an additional level of complication. 

Ishida, H. (1984). A review of recent progress in the studies of molecular and micro structures of coupling agents and their functions in composites, coatings and adhesive joints. Polym. Compo.sites 5, 101-123. 

The transition between cohesive and adhesive failure in a simple bi-material joint has been studied by Kendall (1975). Based on Griffith s energy approach, a criterion is derived for deflection along the interface for a short crack for an isotropic material... 

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