Experimental Analysis of Pressure Sensor Membranes Intended for Vacuum Arc-Extinguishing Chambers in Medium-Voltage Switching Devices.

Abstract

This article presents a comparison of empirical and simulation studies and the parameters declared by the membrane manufacturer. The analysis concludes that these values differ at each stage. Therefore, a numerical and simulation analysis of an optimal flat membrane was undertaken, which will successfully perform measurement functions across the full pressure range without causing inelastic deformations based on a membrane made of 316 L stainless steel with the following mechanical parameters: Young's modulus E=2×1011 Pa, Poisson's ratio ν=0.28, density ρ=7980 kg/m3, and yield strength 2.8 × 10⁸ Pa. A diaphragm with an outer diameter of 25.4 mm, an inner diameter of 2.22×10-4 m, and a thickness of t = 5.08×10-5 m was designed for a pressure sensor in vacuum extinguishing chambers of medium-voltage devices, with a pressure difference Δp from 7 × 10^-4 Pa to 1.013 × 10⁵ Pa. Finite element method (FEM) simulations in the COMSOL Multiphysics environment showed maximum von Mises reduced stresses 1.96 × 10⁸ Pa below the yield strength, confirming operation in the linear-elastic range. The central deflection, described analytically by the equation y=3(1-ν2)Pr416Et3, increased fivefold with an increase in diameter to 3.81×10-2 m (active area A = 1.14 × 10^-3 m² compared to 5.07 × 10^-4 m²), achieving a metrological sensitivity of 9.1 × 10^-10 m/Pa. Experimental studies integrated with Bragg FBG and epoxy adhesive (E = 5 × 10⁹ Pa, tensile strength 4.2×107 Pa) revealed a significant deviation from the manufacturer's catalog data (e.g., deflection of 2.0×10-5 m at 6.89×102 Pa), resulting from uneven bonding and a lack of coaxiality. Corrugated membranes with t = 2.0×10-5 m exceeded plasticity, while the optimized configuration of a smooth membrane with rounded adhesive edges (R=1×10-4 m) enabled precise pressure monitoring below 10-1 Pa, despite technological restrictions on assembly and miniaturization.