Abstract: Random load fatigue tests were performed on the 7475 T761 aluminium dog bone specimens. Some of the specimens were interference fit tapered shank bolt connections(IFBC), and the others were ordinary cylindrical shank bolt connections(OBC). It was shown that fatigue lives of the IFBC increased atuleast by twice as compared with those of OBC for the test stress levels, and the fatigue life increment would increase with the stress level reduction. The main reasons for the fatigue life increment of the IFBC are: (1) The tensile prestresses are introduced in material around the bolt holes, it may reduce the applied alternative stress amplitudes;(2) The pin load distribution on the walls of the bolt holes for the IFBC is more uniform;(3) The initial fatigue quality of the bolt holes is improved by the interference between the bolt and the bolt holes.

Key words: tapered shank bolt, interference fit, fatigue life, random load