Contact Failure Analysis And Structural Optimization Of Multi-Digit Automotive Electrical Connectors

With the gradual enrichment and penetration of functions such as body electronics,passive safety and active safety,the demand for automotive electrical connectors will continue to increase.In the future,automotive electrical connectors will develop in the direction of miniaturization and high density,and the demand for multi-digit electrical connectors from car companies will continue to increase.Due to the characteristics of multiple circuits and important signal transmission,multi-digit automotive electrical connectors are prone to problems such as contact damage and vehicle safety function disorder.They are required to have high performance levels in mechanical properties and electrical properties.Therefore,it is very necessary to study the failure analysis and optimization of multi-digit automotive electrical connectors.The main research contents and results of this paper are as follows:（1）The structural characteristics of the electrical connector contact,housing cavity and assist mechanism have been analyzed,and the insertion and extraction force model and contact resistance model of the OCS064 contact based on the material mechanics and electrical contact theory have been established,and the relationship between its structural parameters and insertion force,contact resistance has been obtained.Combined with the characteristics of miniaturization and high density of multi-digit electrical connectors and the actual working environment,it is analyzed that the failure reason is that the insertion force and contact resistance is too large,which leads to excessive plastic deformation and high temperature rise,causing problems such as instant disconnection and loose contact of electrical connectors.The insertion force and contact resistance are the key factors affecting the contact reliability of the multi-digit electrical connectors,which lays the foundation for the structural analysis and design of the multi-digit electrical connectors.（2）A multi-physics coupling finite element model of electrical connector contacts is established.Taking into account the multiple plug-and-pull cycles caused by multi-party testing and assembly,Abaqus software is used to simulate the plug-and-pull cycle of the structure-electricity-thermal coupling of the contacts according to the actual working current and ambient operating temperature,and the variety condition of contacts insertion force F_C,normal force F_b,maximum equivalent stress S_MAX,gap change valueΔh and contact resistance R_Chas been obtained.Through univariate analysis of the contact model,the influence of the circular radius of the shrapnel,the circular horizontal length of the shrapnel,the width of the shrapnel and the horizontal bonding length of the shrapnel on its mechanical properties and electrical properties has been obtained,which provides help for the reliability design of contacts.（3）According to the force of the multi-digit electrical connectors,the force analysis of the important parts that make up the housing has been carried out.The finite element analysis software Abaqus is used to analyze the assembly stress of the electrical connector and the assembly retention force of the assist mechanism.The simulation results show that the maximum strain of the main rotating blade,rocker and female end plastic shell basically does not exceed the ultimate tensile strain of its material Vydyne R535H,and the strength and stiffness basically meet the design requirements.The mechanical test is carried out on the assist mechanism of the electrical connector,and the results show that the related structure will not fail under actual work.（4）Multi-objective optimization of multi-digit electrical connectors has been carried out.The optimal Latin hypercube sampling method and finite element simulation are used to collect the data of mechanical and electrical indexes of sample points.Comparing the response surface model method and the Kriging model method,the approximate model of the response surface with higher accuracy is determined to use,and the optimal structure of the shrapnel of the multi-digit electrical connector contact is obtained by combining with the NSGA-Ⅱalgorithm.The optimization results show that the change of the contact gap is close to 0,which is reduced by82.2%,the insertion force is reduced by 34.38%,the contact resistance is reduced by15.81%,and the mechanical and electrical properties of the contact are significantly improved.The optimized structure satisfies the application of automotive connectors in multi-circuit functional modules,it will not loosen during operation,and the temperature rise has also been improved.