Experimental Study Of Aluminium/Polycarbonate Sheets Self-piercing "Through" Riveting Jointing Process

Self-piercing riveting joints are an innovative mechanical cold joining technique that finds wide applications in industrial and aerospace fields.As the demand for structural lightweighting in these domains continues to rise,the range of sheet materials used in self-piercing riveting joints is expanding from high ductility materials to low ductility and even polymer materials.The poor fluidity of polymer materials in forming dies has led to problems such as inadequate mechanical internal locking and material cracking,which in turn reduces the joint strength and service life of structural components.Therefore,developing an "efficient" and "reliable" riveting technology that can join thin polymer materials has become a pressing issue in practical engineering applications.To address this issue,this paper proposes self-piercing through riveting joints,and analyses and strengthens their mechanical properties.The paper aims to solve the problem of joining polymer materials by proposing a self-piercing through riveting joints technique and at the same time to study the process tests of self-piercing through riveting joints:To investigate the relationship between the mechanical internal lock structure of the joint and the maximum press load during the forming process of self-piercing through riveting joints under different influencing factors,a finite element model was established.The results indicate that the "U" internal lock structure could be a crucial factor affecting the mechanical properties of the riveted joint.Additionally,the punch speed,the rivet length,the sheet thickness,and the rivet hardness may also impact the final forming quality.A single-factor process test was conducted to analyze the mechanical properties of self-piercing through riveting joints.The test investigated the impact of rivet length,plate thickness,and punching speed on joint performance.Results revealed that an increase in rivet length and plate thickness led to higher failure load and energy absorption values.While an increase in the punch speed caused the failure load and energy absorption values to decrease and then enlargement.With the increase of the pretreatment temperature,the cracks of the piercing self impact riveted joint decrease gradually and the failure load increases first and then decreases.Based on the BBD response surface design method,tests were carried out on AL/PC self-piercing through riveting reinforced joints.In the tests,a multiple regression model was developed with adhesive layer thickness,plate hardness,and punch speed as influencing factors,and joint failure load and energy absorption values as response values,to optimize adhesion-riveting process parameters.Results showed that adhesive layer thickness had the greatest influence on joint failure load and energy absorption value.The NSGA-II genetic algorithm was used to determine the optimum process parameters,namely a plate hardness of 34.45 HRB,an adhesive layer thickness of 0.6 mm,and a punch speed of 26.45 mm/s.The corresponding failure load was2383.10 N and the energy absorption value was 9.20 J.The regression model predicted values were verified with a maximum error of about 10%,verifying its reliability.