NUMERICAL STUDY OF THE PERCUSSIVE RIVETING PROCESS: SIMULATION RESULTS

摘要

Percussive riveting is a widely used assembly method in the aerospace industry. The joints produced using tins technique have consistently high fatigue strength. It is a manual assembly technique but automation has been introduced in certain instances on the work floor to assist assembly workers. In this paper, study was set up to analyze the effect of important geometric parameters on the residual stress and strain distributions within the riveting stackup. In the current paper, a realistic set of boundary conditions have been adopted with both movable riveting die and movable bucking bar in an axisymmetric thermomechanical model that has a countersunk rivet. The knowledge of this evolution is important to gain understanding of the differences between quasi-static squeeze riveting process and the percussive riveting process. The distribution of residual strains and stresses play an important role in influencing the fatigue strength of the assembled joined. Most if not all of the percussive research till date is focused on the process automation advances but enough work has not been done to understand the properties of the assembled joint using the percussive technique. The percussive results will be compared with quasi-static squeeze process results. Strain rate effects and thermal effects are negligible in the quasi-static process while these effects are present in the percussive process. So, the results and observations from quasi-static DOE will he used as a benchmark against which the percussive DOE results will be compared. The Johnson-Cook material model has been used for describing the flow stress of the alloys used in the percussive process.