Fatigue Damage of Rivet Joints in the Condition of Stable Cyclic Load

The article is devoted, to the attempt of working out of a method for determination of period of exploitation for riveting connections with microdefects on the initial stage and propagation of crack to the moment of appearances to the surface. The tested material used aluminum alloy 2024-T3. Experimental researches are realized on flat specimens from an aluminum alloy 2024-T3 with the row of openings for riveting: without riveting (initial state), with a removal of riveting, and also the specimens connected by riveting at stable amplitude loading (tension, σ=100 MPpa) at the coefficients of asymmetry of cycle of R: 0,15;0,3 and 0,5. An origin of local damages in the sheets, and also in riveting connections was controlled by the use of vortex-current defectoscope BD 3-71 with a sensor of a converting type PN-12 MDF 01. Researches of mechanisms of fracture and fatigue were realized with the use of electron scanning microscope of REM of 106I. As a result of these research, information was received about the mechanisms of failure, defined a form and a size of initial damage in appearance in a crack, which can be used as a quality parameter for determination of transitional period of exploitation with microdefects. On the basis of the collected experimental results, statistical description of sizes of local damages was made.