| Summary: | Within the UK steel industry it is believed that continued growth of steel usage in the construction sector would be facilitated by offering multi-material solutions which combine the benefits of several materials (i.e. precoated sheet steels, aluminium alloy, glass, timber and mortar). A review of both traditional and novel joining processes that are currently used to assemble sheet steels indicated that adhesive and sealant bonding has the most potential for joining both multi-metal and fundamentally dissimilar material combinations. Consequently, the aim of this Eng.Doc research project was to establish the robustness of bonded joints, test methodology procedures, and design guidelines for multi-material combinations. The results obtained in this study have shown that a range of structural adhesive and sealant systems exist, capable of producing strong and durable multimaterial joints. The highest levels of durability were obtained with organic coated steel - aluminium or glass joints which restricted the ingress of water to the exposed edges of the bond line. With precoated steel-timber or mortar joints, bond strength was adversely affected by rapid water penetration through the porous timber and mortar adherends promoting joint failure. Furthermore, it was noted that the failure loads obtained with adhesive bonded steel-timber and glass joints were higher than anticipated. This was attributed to a change in the stress distribution, whereby a greater stress concentration was located at the overlap end of the higher modulus steel adherend. Guidelines were developed describing best practice joining techniques for adhesive bonding steel - brittle materials (i.e. glass and mortar), and the requirements for further work outlined to facilitate follow up projects.
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