Inserts for Fastening Sheet Molding Compounds

Abstract

Stainless steel inserts used for fastening sheet molding compound (SMC) are being developed. Using these molded-in inserts, SMC components can be assembled without protrusions. The inserts consist of two mating surfaces which interlock through the existence of a shoulder male boss and a shoulder female counterbore. Repeated assembly and disassembly can take place without damaging the material being fastened. The strength of the joint, when using these interlocking inserts, is comparable to that when using bolts. The joint strength of the whole assembly when immersed in water for a period of time is also investigated. The difference between the dry and wet strengths for the inserted samples is less than that for the bolted samples. Load versus extension plots show that these particular inserts provide a more rigid joint than a bolted connection.