Joining Composite Materials and Structures: Some Thought-Provoking Possibilities

Abstract

Custom-engineered functionally-specific properties leading to greatly enhanced design versatility have drawn designers to composites, but will make these materials-of-preference only if better ways can be found for producing better joints. The very micro- and macrostructure that gives rise to the unparalleled properties possible with composites exacerbates the inherent weaknesses virtually always associated with joints. Prevailing methods of mechanical fastening and adhesive or thermal bonding (welding) are nonoptimal, if not inappropriate, extensions of methods used for joining conventional metallic or polymeric structures with little real change in over two millennia. This paper challenges the old paradigm of joining being a pragmatic process performed as a last step in manufacture and proposes that it must increasingly become an enabling technology that is integrated with material and structure synthesis. Four new ways to think about joining composites are proposed, and a possibility for each approach is presented to provoke thinking among design and process engineers.