A New Study Of Shell Capacitive Pressure Detection System

In the shooting process of the artillery, the chamber pressure and its variation not onlyinfluence the ballistic properties of the artillery but also the global design of the weaponsystem. Therefore, the measurement of the P-t curves of the chamber pressure becomes theprecondition for the design and improvement of the artillery system. However, domestic testmachines are not suitable for the measurement of the chamber pressure of the medium andsmall caliber. Also, the cost of the internal electronic manometer is too high. To improve this,a new capacitive pressure monitor system based on the shell of the manometer is designed inthis dissertation and the problems caused by the large volume and high cost of the testinstruments are solved. Theoretical analysis, computer simulation and experiment have beenemployed together to do the following researches:(1)According to the principle of variable-polar-distance capacity, a coaxial cylindervariable-polar-distance capacitive manometer based on the shell of the manometer is designed.The shell of the manometer is designed according to the theory of thick cylinder andElastic-plastic mechanics. The simulation software of ANSYS is used to investigate itsmechanical property and the feasibility of the shell of the manometer under600MPa pressure.Also, the initial value of the cylinder capacitive manometer and its range of variation aresimulated.(2)Transient tiny capacitive measuring circuits with low-power consumption and smallvolume are designed to adapt to the severe chamber environment such as high temperature,high pressure and strong electro-magnetic interference. The circuits consist of signalamplifying and adjusting circuit, power management module (PWW) and signal acquisitionand storage circuit. The hardware circuits and the sequential control, acquisition and storagemodule, communication interface circuit between the upper and lower computer for the SCMare designed.(3)Computer simulations have been conducted regarding the tiny capacitive measuring circuits. The simulation results are checked to verify the rationality of the design. Theexperimental data is processed and analyzed. The sources of the error of the test system areinvestigated, including the error from the test circuit and the sensors. The integratedmeasurement error is calculated and the rationality of the manometer is verified.