Study On Deformation Behavior And Process Optimization Of Clinching Process For Three-Layer Aluminum Alloy Sheets

An important way to implement lightweight technology is to use aluminum alloy and other light materials to replace steel materials,but because of the difficulty of welding process design of aluminum and its alloy materials,how to realize the connection between aluminum and its alloy plate or parts has become a hot and difficult problem in industry research.Clinching is a plastic connection technology which can realize the connection between plate parts by applying external force to plastic deformation and forming mechanical interlock.As " Aluminum instead of steel" widely implemented,three layers of aluminum alloy plate plastic connection technology has become an important research direction in industry application,because the forming principle of multi-layer clinching is complex,there are more influencing factors,and at present,there are few reports on this aspect,so it is necessary to explore the deformation mechanism of the clinching process of multilayer plate and the method to improve the mechanical properties of the joint.In this paper,theoretical analysis,numerical simulation of clinching process and experimental study were used to study the clinching process of three-layer aluminum alloy sheet.The research results have important reference value for clarifying the deformation mechanism of three-layer sheets clinching and improving the joint performance.The main research work and conclusions of this paper are as follows:(1)Research on automatic finite element modeling of three-layer plate clinching.According to the characteristics of three-layer plate clinching,the forming dies were designed.Based on ABAQUS platform,the finite element model of three-layer plate clinching was established,and the parameterized automatic modeling script and GUI interface were written by using PTHON to realize the automatic generation of the finite element model,which provided a convenient tool for the numerical simulation of large quantities.(2)Numerical simulation study on forming principle and forming law of three-layer sheet clinching.By analyzing the material flow and the evolution of stress and strain during the forming process,the forming principle of the three-layer sheet clinching was clarified,the sensitive process parameters were determined by orthogonal test and variance analysis,and the influence law of the key parameters and the friction coefficient between the sheet material on the joint characteristic structure was obtained.(3)Study on the optimization of three-layer plate clinching.According to the geometrical characteristics of the joint,the evaluation index of the strength of the threelayer plate clinching was analyzed qualitatively.Based on parametric modeling plug-in,Latin hypercube sampling was realized,and the mapping relationship between mold parameters and evaluation indexes was established by using three proxy models.By comparing the prediction accuracy,Kriging model was determined to be better,and the optimal Pareto solution set was obtained by combining NSGA-III multi-objective genetic algorithm.Finally,numerical simulation and experiment are used to verify the results.(4)Study on mechanical properties of three-layer plate clinching.According to the stress of the joint under shear and unidirectional peeling load,three load distribution modes were designed respectively.Combined with numerical simulation and experiment,the failure modes,mechanical strength and energy absorption values of different joints were analyzed,and the joint with better performance was finally determined.