Aiming at the problem of the deterioration of the contact performance caused by the wear debris generated during the fretting wear of the electrical connector, low-frequency fretting wear experiments were carried out on the contacts of electrical connectors, the accumulation and distribution of the wear debris were detected by the electrical capacitance tomography technology; the influence of fretting cycles, vibration direction, vibration frequency and vibration amplitude on the accumulation and distribution of wear debris were analyzed; the correlation between characteristic value of wear debris and contact resistance value was studied, and a performance degradation model based on the accumulation and distribution of wear debris was built. The results show that fretting wear and performance degradation are the most serious in axial vibration; the characteristic value of wear debris and contact resistance are positively correlated with the fretting cycles, vibration frequency and vibration amplitude; there is a strong correlation between the sum of characteristic value of wear debris and the contact resistance value; the prediction error of ABC-SVR model of fretting wear performance degradation of electrical connectors constructed by the characteristic value of wear debris is less than 6%. Therefore, the characteristic value of wear debris in contact subareas can quantitatively describe the degree of fretting wear and the process of performance degradation.

Electrical connectors are the basic components of the electric system in automobiles, aircrafts and ships to realize the current and electrical signal transmission. In the aviation electrical system, the electrical connectors are indispensable supporting devices accessories, which play important roles in connecting electrical system, monitoring and controlling equipment, and provide a guarantee for the reliable transmission of electrical signals between the aviation equipment and system. Whether aviation electrical connectors work reliably directly affects the safety and reliability of the entire aircraft aviation system. The random vibration of aircraft caused by turbulence during flight is one of the main factors affecting the contact performance of the electrical connectors. In this paper, the contacts of the circular four-slot three-pin electrical connectors were chosen as the research specimens. The theoretical model of the contact force for contacts of electrical connectors was established. The test method for contact force measurement was determined. According to the test scheme, the detecting device for the contact force and contact resistance of the electrical connectors was designed, and the turbulence test of the electrical connectors was carried out. Through the analysis of the test data, the influence rule of the turbulence degree, flight speed and flight height on the contact force and contact resistance of the aviation electrical connectors was obtained.

An electrical capacitance tomography (ECT) method was used to detect fretting wear behavior of electrical connectors. The specimens used in this study were contacts of type-M round two-pin electrical connectors. The experiments consisted of running a series of vibration tests at each frequency combined with one g levels. During each test run, the measured capacitance per pair of electrodes was monitored as a performance characteristic, which is induced by the wear debris generated by the fretting wear of electrical connectors. The fretted surface is examined using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis to assess the surface profile, extent of fretting damage and elemental distribution across the contact zone and then compared to the capacitance values. The results exhibit that with the increase of the fretting cycles or the vibration frequency, the characteristic value of the wear debris between the contacts of electrical connector gradually increases and the wear is more serious. Measured capacitance values are consistent with SEM and EDS analysis.

Novel contact materials such as extrinsic conducting polymers can improve contact performance and enable device miniaturisation. This paper presents an investigation of conducting polymer materials used to minimise the effect of fretting slip at the contact interface of connector terminals. Initial experimental studies are presented and a mechanical model is used to describe the polymer interface slip and stick characteristics. For fretting to be minimised the polymer must be sufficiently elastic, with a high coefficient of friction with the contacting terminal, and a sufficient normal force to ensure no slip. Experimental studies of a polymer-tin interface are conducted to characterise contact resistance performance under fretting conditions. A resistance model of the polymer interface is developed.

Electromechanical devices such as relays, switches, connectors and printed wiring boards have shown quick growth along with remarkable progress of electronic products in a recent few decades. For the present, outstanding tasks common to these devices are further downsizing, higher density and broading of bandwidth, on the assumption of keeping high performance and high reliability. These tasks are realized by part production improvement for higher precision and automatic assemblies, development of constituent materials and development of breakthrough structural technologies such as a surface mount technology and an active assembly ferrule technology in optical connectors and so on. In this paper, the technical trends as well as the motive technologies are overviewed for each device.