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.
А.А. Medeltsev, P. А. Shapovalov, М. V. Voronov, А. I. Polukhina, P.N. Sigaleva, А.V. Frolov
2022-04-21
Abstract ▼
The article presents a numerical simulation of non-stationary convective-conductive heat transfer of the strapdown inertial navigation system (SINS), developed in the JSC «CNIIAG». The numerical simulation is carried out in the ANSYS Mechanical. The aim of the study is a comprehensive analysis of heat exchange processes, which are characteristic to the device operation, including mutual spatial influence of thermal powers on each other, as well as on the block of sensitive elements. The simulation of heat transfer inside the hermetic case of the SINS is carried out for critical operating conditions in a strongly and weakly coupled consideration with a comparison of both approaches. ANSYS Mechanical, CFX and System Coupling simulation modules are chosen for program implementation of each approach. The k-e model of air turbulence with implicit consideration of the effect in the boundary layers and diffusion correction in shear flows is chosen for this approach. External heat exchange with ambient air is considered by setting convective boundary conditions on the external surfaces of the SINS, considering their orientation. To obtain numerical values of the heat transfer coefficients, the orientation of each surface in space is taken into account by using the appropriate coefficient. The presence of irregularities on the surfaces of the SINS in the contacts between solid components is considered by using the calculation of thermal resistances of the actual contact and intercontact layer. The simulation results of deformed state of SINS structural system, resulting from the action of a non-symmetric thermal field, is presented. The analysis of the obtained graphs is carried out. Stiffness indicators of the SINS structural system is defined as angles of deviation of sensitivity axes caused by thermal deformations. The obtained results make it possible to evaluate the engineering solutions for the quality of heat removal from the elements of the PCBs, bypassing the sensitive elements of the device, adopted at the stage of product layout.
