High accuracy and improved performance of pressure sensors are essential to ensure safety, quality and efficiency in various industries and machinery. The use of the finite element method (FEM) in the design of pressure sensors makes it possible to improve their accuracy due to a deeper analysis of mechanical and physical processes that arise when exposed to pressure loads. The purpose of this work is to build an accurate three-dimensional model of the sensitive element of the pressure sensor and to analyze the stress-strain state of the elastic membrane under the load from 0 to 15 MPa. The main tasks of the work: research of the properties and parameters of materials used as part of the sensitive element of the pressure sensor based on the structure “silicon on sapphire”; obtaining the values of the maximum equivalent stress arising in the design of the elastic membrane of the sensitive element under the influence of a pressure load of 125% of the nominal value; distribution of radial and tangential deformations of the elastic membrane and determination of the best location of resistance strain gauges on the surface of pressure sensor’s sensitive element. As a result of the research, it was found that the materials used have good resistance to an aggressive environment, as well as the ability to work in a wide temperature range and under high pressure loads. Based on the simulation results, the value of the maximum equivalent stress was determined, the stress value does not exceed the ultimate strength of the sensitive membrane, the distribution of radial and tangential deformations on the surface of the sensitive element was obtained, which makes it possible to determine the most optimal pattern of the resistance stain gauge bridge circuit.
Today pressure transmitters have high requirements such as reliability, quality, measurement accuracy, the ability to work in extreme conditions and resistance to aggressive environments. The main problems in achieving these target indicators are: the high cost of the original products, the laboriousness of the technological process in serial production, and the limitations that affect the accuracy of the indicators of the original devices. Solving these problems is the subject of this article. To solve these problems and improve the physical and mechanical properties of pressure sensor’s sensitive elements, the following tasks are considered in the article: development of a pressure-sensing element design based on the silicon-on-sapphire (SOS) structureresearch on the method of its connection with a ceramic body element and development of a technological route for manufacturing the structure based on “sapphire – vitreous dielectric – ceramic” junction. As a result, the pressure sensor based on the SOS structure has high sensitivity, stability, practically no mechanical hysteresis, and can operate in a wide temperature range from -60 to +350°C when exposed to radiation. In turn, the use of a ceramic base makes it possible to reduce the temperature error of the sensor due to better matching of the coefficient of linear thermal expansion (CLTE) of ceramic (85–100×10-7 K-1) and sapphire substrate (60–75×10-7 K-1), as well as reduce the cost of the technological process due to the use of ceramics instead of expensive titanium alloys and complex metalworking. Thus, the structure "sapphire – vitreous dielectric – ceramic" shows the possibility of increasing the sensitivity of the sensor and reducing the error while expanding its functionality, simplifying the design and improving manufacturability
