Guided wave localization of small defects based on stochastic resonance characteristics of Duffing systems

To improve the location accuracy of small defects in anti-corrosion pipelines by using ultrasonic guided wave, this study developed a guided wave location method for small defects based on stochastic resonance (SR) characteristics of a time-moving Duffing system. Firstly, it solved the shortcomings of the selection of the key parameters of the system, which depended on human subjectivity and lacked interaction correlation in the previous research. By using the stochastic resonance characteristics of the Duffing system, the best fit parameter group of the system was determined synchronously and coordinately. Secondly, with the conjoint analysis of the key parameters of the system and the numerical simulation verification method, found that part of the energy of the noise signal would be transferred to the system output response, leading to the system output response was strengthened. Finally, A time-moving window function was introduced in the experimental verification, and the enhanced system output response in the window was analyzed using power spectral density (PSD), which could realize the location of guided waves with small defects. The experimental result showed that the small defect guided wave with a cross-section loss rate of at least 6 % could be effectively located.