The Effects of Clamping Force and Pre-clamping Force on the Fatigue Strength of Bolt-connection

Abstract

This paper describes the effects of the clamping force and the pre-clamping force on the fatigue strength of bolt-connection. The results obtained are as follows:
(1) The types of load-deflection diagrams of bolt-connection with the clamping force were classified into cross-type and un-cross-type.
(2) And also, theoretical expressions of the optimum clamping force and the pre-clamping force were inducted to the both types of the diagrams.
(3) The theoretical values of the optimum clamping force nearly fitted to the experimental values.
(4) The experimental values of the fatigue limits on the optimum clamping force for the M 5 bolt of bolt-connection increased about 40% against the conventional value, at mean stress σ_m = 30 kg/mm².
(5) The effects of the pre-clamping force on the bolt-connection were inducted with the improvements on the compressive residual stress in bolt-connection and the optimum clamping force.