PIEZOELECTRIC IMPEDANCE-BASED QUANTITATIVE STUDY ON OIL AND GAS PIPELINE CRACK DAMAGE

In order to understand the feasibility for identifying pipeline crack damage degrees using the impedance-based method, the crack damage on pipeline was simulated by artificial methods. A crack damage monitoring experiment was carried based on the piezoelectric impedance method. The PZT impedance signal of piezoelectric ceramic was measured in different damage conditions. Through analyzing the experimental data, root mean square deviation (RMSD) was obtained. According to the variation laws of the damage index and area, the quantifying mathematical model of pipeline damage degrees was established. The experimental results showed that the spectrum curve of PZT electrical impedance was significantly offset to the left, that the peak of frequency was dropped once damage appears, and that with the aggravation of crack damage degrees, damage index values increased, which showed that RMSD can deduce the damage condition. The quantitative assessment of pipeline crack damage can be realized by the established mathematical model in a certain extent.