Researches On Quasi-Dynamic Calibration Technique And Experiment With Plastic Pressure-Measuring Elements

For more than a hundred years, the method of plastic deformation for measuring pressures has been the main means to test the chamber pressure of conventional weapons because of its advantages of reliability, convenience and low price. In our country the method of pressure-measuring with copper cylinders adopts the system of static calibration on the whole. The serious static-dynamic discrepancy will be caused when the copper cylinders statically calibrated are used to measure the dynamic chamber pressure. To decrease the discrepancy, it is important to study the mechanism of the dynamic error and the method of eliminating or correcting the error.The static-dynamic error can be decreased effectively by the quasi-dynamic calibration which is the direction of improving calibration system of plastic pressure-measuring elements. Despite the development of more than twenty years, there are still many problems to be further studied. To make the quasi-dynamic calibration system perfect, much work has been done in this dissertation. The main work consists of the following parts.1.The mathematical model of copper cylinder pressure-measuring system is established according to the pressure-measuring mechanism of copper cylinders and the numerical solution program is made. The simulation of this model has been done and the simulation result agrees with the measuring result quite well. According to the simulating calculation, the regularity of copper cylinder deformation under different pressure is obtained.2.With the mathematical model, the simulation on O 3.5 X 8.75mm pillar copper cylinders for varying the pulse width of the signal has been done. The variation regulation of error by consulting the dynamic pressure corresponding table is got theoretically. It has been testified that the regulation is right.3.A series of quasi-dynamic calibration tests by varying the pressure pulse width for the 3.5 X 8.75mm pillar copper cylinders and O 4.763mm copper spheres are done on the dropper-hammer hydraulic dynamic pressure calibration device. By means of data analysis, the regulations of pulse width's effect on the two types of plastic pressure-measuring elements are obtained. The method ofcorrecting pulse width, which is in accord with the traditional correcting pressure method, is discussed. The polynomial correcting formula and the pressure correcting formula by means of dimensional analysis and similarity theory are obtained. It is testified by the tests that the effect of the correcting formulas is satisfactory.4.The uncertainty of quasi-dynamic pressure corresponding tables is analyzed systemically. According to the data obtained from the calibration process by varying the pulse width, the regulation of error on consulting the quasi-dynamic pressure corresponding tables caused by the variation of the pressure pulse width is explained. And the applicable scope of the 6ms quasi-dynamic pressure corresponding tables is discussed.5.The methods of temperature-correcting on copper cylinders and copper spheres are discussed. The method of unitive temperature-correcting on plastic pressue-measuring elements is put forward for the first time. Large quantities of quasi-dynamic calibration tests in different temperatures are carried out on the dropper-hammer hydraulic dynamic pressure calibration device and the unitive temperature-correcting formula which accords with the traditional correcting method is got. It is shown by the tests that the unitive temperature-correcting formula is credible and the applicable scope of the unitive temperature-correcting formula is discussed.6.Since the monitor precision of quasi-dynamic calibration system is very important,the model of the four channel electric pressure-measuring system in frequency domain is built up. The cause of variance is analyzed. The error function of the system is defined and the formula of correcting the system error is derived.7.The method of quasi-static absolute calibration for the sensors is brought forward in this dissertation. The tests of...