Prybytko I. Development of methods of estimation and decrease of residual stress in pressure sensors.

Dissertation is devoted to the decrease of level of internal stress in metal-glass-silicon joints of sensors of non-electric values with the purpose of increase of level of operating characteristics. Modelling of stressed-deformed state of the welded-soldered constructions of different configuration during the stage of production and exploitation is conducted using the developed method of computation of the stressed-deformed state of multicomponent joints of pressure sensors. It is determined that decrease of level of maximal tension stress in a silicic membrane and insulator is achieved by varying of geometry of silicon-glass-kovar junctions. It is determined that for guaranteeing of given metrological characteristics of converter the joint of sensor must be designed with minimal thickness of sensor element and minimal thickness and height of glass insulator and maximal thickness of intermediate glass element and metallic case. Character of the applied loading and geometrical heterogeneity in form ofcrack-like defects in the area of welded joints influence stressed state during exploitation. This heterogeneity can be dangerous from the point of view of strength of welded silicon-glass joints during work of silicic membrane on tearing. Influence of defects, caused by imperfection of treatment of glass details under welding, is analyzed with the help of approaches of classic mechanics and modern mechanics of destruction. Basic principles of rational structure of joints of pressure sensors are offered on the basis of research of stressed-deformed state of welded-soldered junctions.