Mechanical fastener system for high-temperature structural assemblies

Abstract

A relatively low cost, lightweight and thermal stress-free mechanical fastener system having particular application for reliably joining together high temperature structural members (e.g., a pair of flat fiber-reinforced ceramic composite plates). The mechanical fastener system includes a ceramic composite fastener having a semi-circular head at one end to be countersunk in the structural members to be joined together and a dove tail retention feature formed in the shank or root at the opposite end. The composite fastener has a 2-dimensional (i.e., flat) profile that facilitates an economic manufacture thereof from densified ceramic composite material. A matched pair of thread forms having external threads and an internal dove tail relief to match the dove tail retention feature at the root of the composite fastener is held in face-to-face mating engagement with one another so as to establish a mechanical interlock around the root of the composite fastener. A 2-dimensional ceramic backing washer has a rectangular center hole dimensioned to receive the root of the composite fastener therethrough. A nut having internal threads that correspond to the external threads of the pair of thread forms is rotated into surrounding engagement with the thread forms to prevent a removal of the composite fastener and a separation of the structural members.