Study On Electrical Contact Reliability Of SMA Connector

Electrical connectors are widely used in various industries such as electrics and automobiles.And because of their complicated and harsh working environment,electrical connectors have become weaker parts of the system.Therefore,the reliability of electrical connectors is becoming more and more important.In this thesis,the structure and electrical contact reliability of the selected SMA connectors were studied through theoretical analysis,finite element simulation analysis and micro-vibration experiments.The specific research contents are as follows:Firstly,two theoretical models of insertion force are established and the influence of the structural parameters on the insertion force is studied.It's concluded that the small changes of the chamfering of the contact parts will have a great influence on the pulling force.And the influence of the inner diameter,closing amount and outer diameter of the socket,the diameter of the pin,the slot width,the coefficient of friction and the length of the shrapnel on the stable value of the insertion force decreases in turn.And the structure of the SMA connector is optimized and the maximum value of the insertion force is reduced obviously.Secondly,a theoretical model and a finite element simulation model of electrical contact are established.The influence of the parameters on the contact state of the connectors is studied.The study shows that the diameter of the pin and the inner diameter of the socket affect the contact area directly while the outer diameter,the closing amount,the length and the slot width of the socket directly influence the contact pressure and the influence of the above parameters on contact pressure decreases in turn.The contact resistance is inversely proportional to the contact area.The friction coefficient(0.1-0.3)has little effect on the contact of the contact parts.Finally,based on the self-developed vibration system,the insertion force and vibration experiments were carried out.Through the insertion force experiment,the reaction of some defects of the connectors in the insertion force is obtained,and the correctness of the theoretical model and the simulation model in Chapter 2 is verified.The effects of insertion force,vibration frequency and vibration amplitude on resistance are studied through the vibration experiments.Studies have shown that the greater the stable value or maximum value of the insertion force and the lower the frequency,the faster the contact resistance value in the micro-movement reaches the set value(5m?).But for the vibration amplitude,while the time required for the resistance value to reach a relatively large value is obvious shortened as the vibration amplitude increases,the effect of the amplitude is not significant when the smaller value(5m?)is used as the setting value.