Research On Coupling Failure Mechanism And Reliability For Electrical Connector

With the continued progress of science and technology,the human society is entering the information age.All kinds of electromechanical devices and electronic products are constantly emerging and upgrading,which has unprecedented influence on people's life and work.Electrical connectors are one of basic connection components,which have been widely used in military and civil areas,such as weapons and equipment,electronic products and so on.Moreover,equipment and products can be modular due to the connection effect of electrical connectors.Normal operation of the equipment and system depends on their quality and reliability that is causing people's significant attention.Because the work environment and use condition is complex and tough for electrical connectors,the high requirement has to be put forward to satisfy their manufacturing process,mechanical structure and electrical properties.Therefore,it is necessary to carry out the research on the reliability of electrical connectors,which can improve product design and manufacturing process,ensure safe and reliable operation of the mechatronics equipment and communication system.Meanwhile,the research has important practical significance in enhancing our country's core competitiveness in the field of electronics manufacturing.In view of electrical connector reliability issues,this paper studied the analysis models and technical methods of several kinds of typical electrical connectors in terms of the manufacturing process,fatigue failure,multi-physics coupling and signal integrity.The specific research included five parts as follow.(1)The laser soldering technology which can improve the connect function and manufacturing capability of the Micro-USB electrical connector was presented in this section.The traditional welding process was hard to handle micro-joining of thin wires within electrical connectors,so the finite element modeling method based on laser soldering mechanism was adopted and the finite element model of laser soldering joints was established.After the actual working state of the electrical connector was simulated by the temperature cycle effect of thermal accelerating experiment,the stress and strain distribution can be obtained in the finite element analysis.The crack initiation of solder joints can be found through failure analysis,and the fatigue life of solder joints can be predicted by combining with the Coffin-Manson method.The fatigue life prediction results showed that the reliability evaluation on laser soldering joints met the manufacturing standard of electrical connectors,which made the laser soldering technology be widely promoted in practical manufacturing and application.(2)The unified parameter contact mechanics model was raised on analysis of the insertion-withdrawal feature and fretting wear for electrical connectors.For complex electrical connector structure and mechanical behavior,the change of structure parameters was analyzed during the insertion-withdrawal process,which had an impact on the mechanical property about electrical connectors,according to elastic mechanics and contact mechanics theories.Then the unified parameter contact mechanics model was established.Change rules of the insertion force and withdrawal force can be found out,after studying the insertion-withdrawal feature of the male or female terminal inside of the high-speed backplane connector.The mechanical model was verified and the insertion force was optimized.Through comparing the simulation results with testing results,the optimized insertion-withdrawal force met the standards.(3)Dynamics analysis and fatigue life evaluation were carried out for the Micro-D electrical connector with complex structure,which were based on the proposed unified contact mechanics model above.Combined simulation with testing,the stress distribution and contact area changes about the twist pin and socket of the electrical connector can be obtained from the insert and fretting process.The relationship between the contact area or contact resistance and the fatigue life cycles can be determined.Meanwhile,the effectiveness of the fatigue life evaluation can be verified by testing for the electrical connector.(4)Due to the limitation of traditional simplified models,an electrical-thermal-mechanical multi-physics coupling model was presented for the USB electrical connector under the complex environment.Firstly,the electrical-thermal coupling relationship was got from electric field changes and temperature field changes caused by electric field,which adopted the finite element method to analyze the electrical connector in work.At the same time,corresponding current distribution and temperature distribution were obtained too.Then,the thermal-mechanical coupling relationship between temperature field and stress field was found out according to the temperature distribution and the stress distribution caused by it.The applicability of the electrical-thermal-mechanical multi-physics coupling model on the electrical connector was verified by the analysis of characteristic parameters,which were derived from the electrical-thermal coupling and thermal-mechanical coupling.(5)An optimization method of high-speed interconnect performance based on signal integrity analysis was proposed to deal with the signal-loss problems during the data transfer for high-speed backplane connector.The HFSS simulation analysis based on the transmission line theory was adopted to gain corresponding parameters,such as characteristic resistance,insertion loss and return loss,far-end crosstalk and near-end crosstalk.These parameters were improved and corrected necessarily after optimizing,and were tested by the relevant equipment.The effectiveness of the proposed method can be verified by comparing the simulation and optimization results with testing results.It is proved to be a feasible analysis method to solve the problem of high-speed interconnection.The existing fatigue failure and reliability problems of electrical connectors in the service process were studies by theoretical analysis,modeling,numerical simulation and testing in this paper.The proposed analysis models and technical methods are able to be used to deal with a series of key problems about electrical connectors.Therefore,there are guiding significance and reference value in further optimizing the structure,enhancing the level of performance and reliability for electrical connectors.