SHM of Thick Structures via E/M Impedance of Embedded PWAS for Weight Loss Defects
Abstract »In this study, the coupled field finite element analyses (CF-FEA) were conducted to simulate the electromechanical impedance spectroscopy (EMIS) of a piezoelectric wafer active sensor (PWAS) in order to monitor the structural weight loss mechanisms on thick structures. In particular, we have modeled a 2-D and 3-D thick steel structure in thickness of 5mm and 10mm to simulate a corroding plate-like naval structure. Then, we instrumented the thick plate with a PWAS to obtain the EMI spectra in the range of 100 Hz – 15 MHz including longitudinal-wise and thickness-wise modes. We then further focused on the thickness modes in relatively high frequency range to observe the effects of weight loss through the thickness of the plate due to the corrosion. We further conducted a statistical study to generate a damage index through root mean square deviation (RMSD) method to quantify the effects of the weight loss due to the corrosion. The paper ends with summary conclusions, and suggestions for future work.
Biography: Conducted original research in the laboratory for active materials and smart structures (LAMSS). Proactively involved in SHM and active sensing related projects. Performed theoretical developments for modeling thickness mode E/M impedance spectroscopy (EMIS) of PWAS; developed Proof mass PWAS (PMPWAS) transducer for tuning wave modes; developed analytical EMIS model of Bio-PWAS; and developed a guided wave technique in welded thick structures by the weld guided quasi-Rayleigh wave.