Design of Mechanically Fastened (Bolted) Joints in Automotive Composites
This paper discusses the design issues related to bolted joints in automotive composites. Pin bearing strength and fatigue test results of bolted joints in both random fiber as well as continuous fiber sheet molding compound composites are reviewed. Fatigue failure modes in bolted joints of these composites are presented. Based on these tests, design guidelines for bolted joints in sheet molding compound composites are proposed. Sheet molding compound (SMC) composites and resin transfer molded (RTM) composites are being considered for applications in automotive chassis components, such as cross members, wheels, and front end structures. Mechanical fasteners will be used to attach these composite components to their supports or other structures. While adhesive joints are preferred in body applications, mechanical fasteners, such as bolts and screws, have some distinct advantages in chassis applications.