Research Of Rivet Deformation And Structural Optimization Of Riveting Die With Electromagnetic Riveting

Aircraft riveting parts are prone to fatigue failure. Appropriate interferencecan effectively improve the fatigue life of the riveting piece. Because of the highforming rate electromagnetic riveting can form uniform amount of interferencealong the rod and allow to form a lager interference. But the interference is lessthan optimal amount of interference using flat riveting die. Therefore in order toimprove the fatigue life of riveting piece it is necessary to study the rivet deforma-tion and structure optimization of the riveting die in electromagnetic riveting.Aiming at the way of rivet deformation in electromagnetic riveting, firstlypropagation of stress waves in a slender rod was analyzed. In addition stress wavepropagation models in the elongated rods of loading one end and loading both endsware deduced. And then analyszed the stress state of rivet in the process of elec-tromagnetic riveting in theory, formula of riveted force in each stage ware estab-lished by slab method. Provided theoretical basis for the selection of riveting forceon the practical production.Numerical simulation of the electromagnetic riveting process was studied byAbaqus software. Analyszed the dynamic deformation process, getting the changeregulation of equivalent plastic stress and strain of rivet with time. The distributionof shear stress and residual stress ware also studied when the riveting process wascompleted. On this basis researched the influences of the riveting die radius andriveting die angle on the distribution of residual stress, the size of amount of in-terference, the maximum shear stress and the maximum residual tensile stress bychanging the riveting die radius and riveting die angle. Fitting the data by Matlab,the functional relationship between the above parameters and riveting die radiusand riveting die angle ware established. The fatigue life of the rivet was analyzedby Fe-safe software to determine weak parts and how residual stress influenced thefatigue life of the riveting piece. The results showed that the fatigue life increasedexponentially with the increse of residual compressive stress. The objective func-tion ware established based on fatigue analysis results and the best selection of theamount of interference and optimized the structure of the riveting die. Finally,verified the optimization results by experiment. The results showed that the rivet-ing die designed can effectively improve the fatigue life of the rievting piece.