| Tantalum electrolytic capacitor is one of the most basic and important electronic components of the whole machine due to its small size and large capacity.It is widely used in military communication,aerospace and other fields.Tantalum capacitors often experience high-frequency vibration(vibration frequency above 1000Hz)in the working process.Strong vibration will seriously affect the structure and performance of tantalum capacitors,even physical failure,such as anode lead fracture,anode block damage,poor contact,de-welding and so on.In order to solve the engineering problems of tantalum capacitors applied in strong vibration environment and determine the adaptability and structural integrity of tantalum capacitors to high-frequency vibration that may be experienced in field use,high-frequency vibration analysis and test are often required.The traditional high frequency vibration test is carried out by using the vibration test bench.However,due to the small size of tantalum capacitors and the special packaging form of finished products,it is difficult to obtain the dynamic response characteristics of the internal structure such as stress and strain during high-frequency vibration,which limits the testing of the structure’s vibration resistance,reliability and integrity.With the development of computer technology and finite element method,computer finite element simulation provides a powerful tool for high-frequency vibration analysis of tantalum capacitors.Tantalum capacitor vibration environment belongs to the high frequency of forced vibration,based on high frequency vibration test conditions(GJB360B-2009),and use the advanced numerical simulation software COMSOL Multiphysics tantalum capacitor high frequency vibration analysis research,found that the physical failure mode of the tantalum capacitor anode lead anode block in the vast majority are breaking and contact points in adjusting shim.At the same time,there are cracks on the anode block where the lead is broken.There are many factors affecting the structural stability of tantalum capacitors under vibration state,including diameter d of anode lead,vibration acceleration level a,adjusting gasket material(PTFE or rubber)and structure,adjusting contact area ratio S between gasket and anode block,adjusting contact pressure F between gasket and anode block and friction coefficient F.At the same time,each factor contains multiple factors(levels).The simulation results show that the maximum internal stress of tantalum capacitors increases rapidly with the increase of vibration acceleration level a.With the increase of friction coefficient μ,the internal maximum stress value of tantalum capacitor gradually decreases,and the larger the anode lead diameter d is,the less it is affected by friction coefficient f.With the increase of the contact pressure F,the maximum stress value in the tantalum capacitor gradually decreases,and the larger the anode lead diameter d is,the less it is affected by the contact pressure F.With the increase of the contact area ratio S between the adjusting gasket and the anode block,the maximum stress value of the capacitor gradually decreases and becomes flat.Using the improved new type of claw type adjusting shim tantalum capacitor by further simulation,vibration test and electrical performance test,found that optimization of the structure of the internal stress variation can significantly reduce the vibration in the process of capacitor,improve the tantalum capacitor structure stability and reliability in the vibration environment and meet the requirements of electrical properties.The optimized tantalum capacitors have good engineering application value and have been mass produced in relevant military enterprises.The relevant theoretical and experimental research in this paper has certain significance in guiding the design,manufacture and optimization of capacitors. |
