Mechanical fastening of polymer composites

Abstract

AbstractIn structures composed of polymer materials and polymer matrix composite materials, components must be joined such that the overall structure retains its structural integrity while it is performing its intended function which can include both mechanical loads (static and dynamic) and environmental loads (temperature and humidity). The use of composite materials in complex structures almost always reduces the number of components in the structures compared to the use of metallic alloys for the same structure. Thus, using composite materials not only results in great savings in weight, but also through a reduced number of joining operations, results in significant savings In assembly, inspection, parts storage, and movement, resulting in increased reliability and lower cost. Yet joining is still required. Joining metallic structures is a mature technology involving riveting, bolting, welding, glueing, brazing, soldering, and other methods. However, for most polymer matrix composites only adhesive bonding and mechanical fastening can be utilized. Attention has been given recently, however, to localized welding of thermoplastic polymer matrix composites. Inherently, adhesive bonding is preferable to mechanical fastening because of the continuous connection, whereas in drilling holes for bolts or rivets, fiber or other reinforcements are cut, and large stress concentrations occur at each discrete fastener hole. However, in many structures, it is necessary to employ mechanical fasteners in order to remove components or to have access to the interior of the structure. Hence, both adhesive bonding and mechanical fastening are important in joining structural components of polymer or polymer matrix materials. The following is a review of much of the literature dealing with mechanical fastening of polymer matrix composite structures. Hopefully, it provides an overall introduction for detailed study of the referenced documents as well as others, and a catalyst for further research.