Abstract：Based on the finite element analysis(FEA)method,the distortion coefficients of the 600kPa gas piston gauge and 500MPa oil piston gauge are computed. According to the coupling relationship between the pressure distribution in the piston-cylinder gap and the gap distortion, the final pressure distribution and gap values under a certain measuring pressure are determined by iteration calculations.Based on this, the effective areas of piston gauge at various pressure points are calculated, and the pressure distortion coefficient is obtained by the least-square fit. A script for computation is developed using Python and ANSYS APDL. The influence of tuning parameters on the results is studied, and the uncertainty of the computed distortion coefficient is estimated. For the 600kPa gas piston gauge, the difference between the computed distortion coefficients by FEA and simple theory is only 0.8%. For the 500MPa oil piston gauge,the distortion coefficient computed by FEA is consistent with the value from experimental measurement within the uncertainty.
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2024, Vol. 45 
