Study Of Test Conditions In Particle Impact Noise Detection For Sealed Relays

Sealed relay is a kind of electronic component which can perform signal transmission, execution control and power distribution. Its reliability influences the whole aerospace electronic systems. The remainder in the relay is the primary failure source of sealed relay. Particle Impact Noise Detection (PIND) test is the industry criterion and is also a screening experiment which must be passed by sealed relay. However, a large number of examples show that is difficult to activate the remainders with high adsorption ability for current PIND test conditions, and is prone to misjudgment, need improved as soon as possible. Currently the study of activation process, the extreme and the expansion of PIND test conditions are poor, which can result in misjudgments and cannot show the maximum detection capability. To address these problems, experimental system is set up. In order to obtain the optimal detection conditions, the factors of activating remainder and extreme conditions are investigated. The novel method of PIND test is then proposed, which can show the maximum detection capability. The research on PIND has important theoretical and practical value for improvement of the reliability of sealed relays and aerospace electronic systems.Firstly, experimental systems are set up. The method of random vibration is firstly applied to PIND test for sealed relays. The auto PIND system can output sinusoidal vibration, random vibration and shock vibration conditions. In order to observe the movement of remainders during PIND test, a new method based on high-speed video technology is proposed and the movement analysis system is also presented. This method offers an intuitive means to verify the PIND test conditions.Secondly, the factors of activation conditions are investigated. Simulation model of activation process is established. The method of simulation is proposed for sealed relays, and the characteristics of the activation effect are also presented and verified for different detection conditions. Combined the theoretical derivation and experiment study, invalid activation frequency is presented. Based on the characteristics of the electrostatic adsorption for remainder within the sealed relays, the solution of decrease electrostatic adsorption is presented.Thirdly, extreme PIND detection condition is studied. Damage mechanism of detection condition is studied for sealed relays, evaluation standards of extreme PIND detection conditions is also presented. The method of analyzing extreme PIND detection condition is presented. On the premise of being undamaged, extreme vibration and shock test conditions are proposed and verified. Finally, optimum detection condition is studied. The remainder’s motion model of excitation process is established, simulation analysis of excitation is also presented. Experimental method and simulation analysis method are adopted to study the relationship between parameters of test objects and the influence how the vibration test conditions affect the detection effects. Orthogonal design method and range analysis method are raised to study the influence how the vibration test conditions affect the detection effects. According to different purpose of use,4groups of optimum vibration test conditions and3groups of optimum shock test conditions are proposed. Therefore, a new method of PIND detection for sealed relay is proposed, comparison with the method prescribed by GJB65B proved that the new method can effectively improve the detection capability of PIND.