| With the increasing advancement of the automotive industry,the development of lightweighting technology for automobiles has become mainstream.Using TRB variable thickness plates to manufacture stamped automotive covering parts has become a new approach.Studying the stamping and deep drawing of TRB plates has guiding significance for achieving lightweighting technology for TRB plates in automobiles.Secondly,in actual production,the unevenness of wall thickness occurs during the deep drawing of cylindrical parts,which manifests as a thinning of the wall thickness at the flange and an increase in wall thickness at the upper end of the cylinder wall.This wall thickness unevenness not only affects the appearance,assembly accuracy,and performance of the formed part,but also leads to increased mold wear and subsequent processing difficulties,higher costs,and lower material utilization efficiency.To address these issues,this thesis focuses on the uneven wall thickness problem that occurs during the deep drawing of small-sized cylindrical aluminum alloy discs,and proposes a solution using precision forming and introducing TRB plates with continuous thickness variation.Traditional equal thickness plates are transformed into TRB plates,and the use of TRB variable thickness plates solves the problem of wall thickness uniformity in the deep drawing process of cylindrical parts.Based on the traditional equal thickness plate deep drawing simulation,the structure parameters of the TRB plate are designed in reverse according to the wall thickness variation law of the cylindrical part,and the structure parameters of the TRB plate are optimized using the response surface method.Finally,a sparrow search algorithm-optimized SSA-BP neural network model is constructed to achieve the nonlinear mapping between the structural dimensions of the cylindrical part and the TRB plate structure parameters,thereby achieving the goal of cost savings,improved material utilization efficiency,and production efficiency.The main research contents are as follows:(1)The characteristics of deep drawing of cylindrical parts are analyzed,and nine sets of finite element models of small size cylindrical parts with different structural dimensions are constructed for forward simulation.The distribution law of wall thickness after forming of cylindrical parts is analyzed.According to the change law of wall thickness,the cylindrical parts are divided into three regions: the bottom region with constant wall thickness,the region with reduced wall thickness and the region with increased wall thickness.(2)Reverse design of TRB variable thickness plate to solve wall thickness nonuniformity: use TRB thickness plate to compensate for wall thickness reduction in the fillet area and reduce wall thickness increase in the cylinder wall area,where TRB plate thick area compensates for wall thickness in the fillet area,and TRB plate thin area weakens the wall thickness in the cylinder wall area.The specific means are as follows:According to the wall thickness distribution rule that the wall thickness of the cylinder bottom area remains basically unchanged,the wall thickness of the fillet area decreases,and the wall thickness of the cylinder wall area increases after the cylinder part is formed,the cylinder part block area is subdivided into five sections: the wall thickness unchanged section,the wall thickness sharply reduced section at the intersection of the fillet and the cylinder bottom,the minimum wall thickness section of the fillet,the wall thickness recovery section at the intersection of the fillet and the cylinder wall,and the maximum wall thickness section at the upper end of the cylinder wall.The point tracking function of Deform software is used to reversely calculate the lateral position of each point at the junction of each segment of the cylindrical piece at the blank,thereby setting the structural parameter size of the TRB plate along the length direction;A single factor experiment was conducted to investigate the effects of thick and thin zone thicknesses on the wall thickness uniformity in the three regions of a cylindrical part,including the fillet region and the cylinder wall region,where the wall thickness varies.Orthogonal experiments were established to verify the effects.(3)Optimization of TRB structural parameters using response surface method:Aiming at selecting four structural parameters of TRB plate,namely,thickness of thick zone,thickness of thin zone,length of left transition zone,and length of right transition zone,as design variables,and taking the maximum wall thickness of fillet region,minimum wall thickness of fillet region,maximum wall thickness of cylinder wall region,and minimum wall thickness of cylinder wall region as the goal of forming wall thickness uniformity optimization,response surface experiments were designed based on BOX Benhnkn,Obtain finite element simulation test sample data through Deform software,and establish a quadratic polynomial regression response model through data analysis and processing to optimize the structural parameters of TRB plates.(4)Establish a neural network model to realize the nonlinear mapping between the structural dimensions of cylindrical parts and the structural parameters of TRB plate: Use the BP neural network method to construct the structural parameter model of TRB plate,and introduce the sparrow search algorithm to improve and optimize it.According to the determination of the neural network model structure and related parameters,complete the establishment of the structural parameter model of TRB plate.The trained neural network is validated by establishing three sets of numerical simulations for the deep drawing process of small sized cylindrical parts. |
