Simulation And Experiment Of Hammer Riveting Process In Aircraft Skinning

In the aircraft assembly riveting technology,pneumatic riveting robot has the obvious advantages of compact structure,low cost and flexible use,which can be used to complete the riveting assembly of fuselage siding and other structures.In this paper,based on the hammer-riveting technology,the pneumatic hammer riveting technology of aluminum alloy rivets is studied.The computer simulation of the riveting impact principle of pneumatic hammers and the rivet deformation mechanism based on wave dynamics was carried out through theoretical analysis methods and process tests such as finite element analysis.And the relevant process test is designed and completed,and the theoretical validated.For the pneumatic hammer riveting impact system,the hammer riveting process is analyzed first,and the forming model of the hammer riveting impact system is established.The principle of pneumatic riveting gun was analyzed and the rivet mathematical model was established.The initial velocity before piston collision was obtained.The collision process of piston and punch and the impact and impact process of rivet were simulated by finite element method.By comparing with the experimental results,During the first impact of the system,the initial velocity of the piston is corrected so that the simulation conditions are close to the real ones and the accuracy of the simulation results is improved,which provides the foundation for the next simulation analysis.Based on the wave dynamics theory,the rivet impact deformation process is explained and analyzed.Firstly,the propagation characteristics of the elastic-plastic wave in the slender rod are analyzed,and the mathematical model of slender rod under shock load at one end of the slender rod is established.Secondly,the deformation process of the rivet is divided into stages,and the stress state Compared with the finite element simulation results,the validity of the deformation state of rivets based on wave dynamics was verified.On the basis of completing an impact analysis on the initial piston speed correction,the multiple impact process of the hammer rivet is further simulated and the relationship between the theoretical process parameters is obtained.According to the result of hammer riveting deformation under different pressures obtained through simulation analysis,the analysis results of the stress and rivet impact of riveting deformation process and the impact times of riveting to complete deformation are obtained.Based on the Python language,the secondary development of ABAQUS finite element software was carried out.The automatic simulation program of hammer ripple continuous impact was established and the efficiency of hammerriveting simulation analysis was improved.A three-coordinate dual-robot riveting experimental platform was set up to carry out the riveting process test.Through the force sensor,the impact force of the rivet in the riveting process under different pressures was collected,and the coefficient correction of the one-shot impact simulation model was completed.The comparative analysis of multiple impact simulations and test results verifies the rationality of the working process of hammer rivet impact system and the effectiveness of the simulation method.By comparing the theoretical analysis results with the stress states of the simulation results,the correctness of the rivet deformation mechanism is verified.