Standard Fatigue Test Specimens for Fastener Evaluation

Abstract : An AGARD coordinated programme which examines the fatigue performance and joint characteristics of a number of mechanically fastened joints has been completed. This report describes the programme which examines mechanically fastened joints with 1) no or low secondary bending and 2) with high secondary bending. In part 1, three types of joint are assessed which exhibit no, low and high amounts of load transfer by the fastener. The no load transfer joint was rejected and the low and high load transfer joints were considered to be equivalent in rating fastener systems. In part 2, three types of single shear joint are considered. They are compared on basis of load transfer and secondary bending characteristic and also on the fatigue endurance with a range of fastener systems installed. Only one joint, the UK designed Q-joint, adequately fulfilled the requirement of a standard joint for fastener evaluation purposes.