The Analysis Of Residual Stress In Glass-to-Metal Seals For Triax Connector

Glass-to-metal sealed connectors,whose performance is very critical,are widely used in air-sealing applications such as aerospace and other important areas.With the development of military connectors,the demand for high-performance glass-to-metal sealed connectors is also increasing.Due to complexity in glass-to-metal sealing technology,the development process of new connectors is often complicated,hard,expensive and troublesome.During the cooling process of the seal,residual stresses is a necessary result of the huge difference of material properties between of glass and metal.Excessive residual stress can destroy the sealing interface and cause breakage,which is the main reason for damages of connectors.In this paper,in order to discuss the rationality of the structural design of a new triaxial connector with glass-to-kovar alloy sealing and verify its sealing quality,the residual stress are analyzed under mature match seal manufacturing process.Firstly,according to the manufacturing process of the connector and glass-to-metal sealing theory,the residual stress during natural convection cooling from the annealing temperature to the room temperature was calculated by ANSYS software.The simulation results show that the residual stress mainly occur near the sealing interface,in which the metal is in tensile stress state,the inner and outer glass tubes are in compressive stress state,and the stress of inner glass tube is larger than outer glass tube.The effect of the mold and the cooling rate also is analyzed,and found to be suitable for small components by air-cooling directly.Secondly,the residual stress in the glass tube was measured by the stress-optical path difference method.The measured magnitude of stress generally agrees with the simulated one and uneven distribution of stress in the glass tube was also found.In addition,a temperature impact fatigue test was carried out to investigate the sealing quality of connectors.After 500 cycles,the leakage rate of all samples still meets the requirements.Finally,the effect of the sealing length,the glass tube thickness and the shoulder of the contact are analyzed.The above research shows that residual stress in the new connector is small,the structural design of the sealing component is reasonable,and the sealing quality is reliable.