Transfer matrix Method-based dynamic model to compensate the pulsating pressure in Strain-based nonintrusive pressure measurement for the L-shaped pipe

Abstract

Currently, the strain-based nonintrusive pressure measurement does not consider the dynamic case, errors could be introduced. However, the calibration of the dynamic strain-pressure sensitivity coefficient (DSSC) is complicated due to the need to design a special standard dynamic pressure source for different pipes. To address this issue, the present study introduces a model-based and easy-to-implement approach to calibrate it indirectly. Firstly, the baseline dynamic model developed by transfer matrix method is calibrated with the tested static strain-pressure sensitivity coefficient and natural frequencies utilizing model updating. Secondly, the DSSC is generated by the calibrated dynamic model to compensate the dynamic pressure. The closed-form sensitivities of the DSSC and natural frequency are derived to conduct the parametric sensitivity analysis to select the reasonable parameters to calibrate the analytical model. The uniqueness of the field transfer matrix is also proven strictly to make sure the output from the model is unique. The case studies showed that the maximum relative errors of the natural frequencies and closed-form sensitivities predicted by the presented method to the tested results in the existing literature and those predicted by finite difference method are −10% and 1.20% respectively. The experimental results indicated that the proposed method can reduce the maximum relative error of the dynamic pressure to the one measured by commercial pressure sensor from 13.04% to 4.35%.