A damage initiation and evolution criterion was adopted based on the equivalent plastic strain and stress triaxiality, taking the TC4 titanium alloy bolts commonly used in aviation for example, the finite element model was established for a typical lap joint of non-plate nut. The stress details, plastic deformation and failure mode of the lap joints were analyzed, and the tensile-shear static tests and tensile fatigue life tests of the lap joints were carried out. The testing results show that the finite element simulation model is in good agreement with the test load curve, and the deviation of the failure load from the testing result is less than 5%. There is a gap between the inner wall of the nut and the outer circle of the bolts, and the lap joint contacts with the inner wall of the nut after deformation to form a support reaction forces during the processes of static tensile-shear loads. And there is an angle of about 83° between the final section and the axis of the bolts. Compared with the self-locking nut of the same specification, the tensile-shear failure load of the lap joints is reduced by 5%~7%, but the fatigue life is increased by 19%~182%. Different from the static tensile-shear test, the failure form of the fatigue life tests is the fracture of the connecting interlayer.
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