Based on the particularity of aero-engine bolted joints and the axial stress distribution of bolted joints of different styles,the stiffness theory of aero-engine bolted joints was proposed,and the effects of load and structure parameters on the joint stiffness were further studied. The results indicated that when the bolt numbers n changed between 4 and 30,the dimensionless bolted joint stiffness K of double members varied linearly between 8.9 and 66.8. When the bolt preload Fpwas small,the dimensionless b...