Research On The Forming Quality Of Rotated Clinching Of Aluminum Plate

With the development of science and technology,people's pursuit of lightweight is increasing,and light-weight and high-strength sheet materials are used in various fields.How to better realize the connection of these sheets has become a main research direction.Rotated rolling clinching connection process is a new type of sheet metal connection process,which is based on the traditional semi-hollow rivet self-piercing riveting and mechanical clinching.The sheet metals are extruded by a pair of rotating synchronously punches,then a non-circular mechanical interlocking point is formed in the cavity of the concave mold.In this paper,a method that combinate the experiment,numerical simulation and theoretical analysis is used to study the rotated rolling clinching technology.The main tool dimensions of rotated clinching connection were determined by numerical simulation,the test device was developed for rotated clinching forming,and the rolling clinching tests were carried out under the conditions of different process parameters and tool parameters of reduction H,joining speed v,punch spacing?d and die depth h.The rules of formed joint with different parameters were analyzed;The influence of different parameters on the connection strength was analyzed by shear and tensile mechanical tests.The failure forms of joints by rotated rolling clinching connection under different loads are analyzed and the method to determinate the failure forms of joint is put forward.The main conclusions obtained from this study are as follows:(1)The developed test device can be used for rotated rolling clinching connection of aluminum sheets.It is convenient to operate and can adjust the punch spacing?d and the thickness of the sheet to be connected.(2)The maximum forming force is positively related to the amount of reduction H.With the increase of H,the interlock value T_u first increases and then decreases,the bottom thickness value x gradually decreases,and the neck thickness value T_n basically remains unchanged.The greater joining speed v,the faster the forming force increases.The interlock value T_u and the neck thickness T_n both increase at first and then decrease,and the bottom thickness x basically remains unchanged with increasing of joining speed v.As the punch spacing?d increases,the interlock value T_u gradually increases,the neck thickness T_n first increases and then decreases,and the bottom thickness x basically remains unchanged.As the die depth h increases,the interlock value T_u first increases and then decreases,the neck thickness T_n first increases and then decreases,and the bottom thickness x gradually increases.(3)The shearing and tensile force of the joint increase first and then decrease with the increase of the reduction amount H,die depth h and the connection speed v;but as the punch spacing?d increases,the shearing strength of the joint first increases and then decreases,while the tension strength of the joint increases linearly.(4)A method based on three coordinates is proposed to judge the failure of joints by rotated rolling clinching,which can effectively judge the failure of shearing and tension.(5)The shearing failure modes of joints mainly include:peeling failure,peeling both and shearing failure,and double-point shearing failure;the smaller of joining speed v and die depth h,the joints are prone to occur peeling failure.The tensile failure modes of the joining joint include:peeling failure,peeling both and shearing failure.With the increase of the punch spacing?d,the joint is prone to peeling both and shearing failure.From the above research results,it can be seen that the process parameters and tool parameters are the key factors that affect the forming law,strength and failure mode of the joint by rotated rolling clinching.The research results in this paper will provide a reference for the follow-up research on the rotated rolling clinching technology.