Method of detecting reducing fatigue crack of structure using spectral noise reduction based on long short-term memory network and nonlinear ultrasonic modulation and system for the same

摘要

Disclosed are a method for detecting fatigue cracks in a structure and a system for the same. The vibration detection device detects the vibration of the structure that occurs when the structure is excited at low and high frequency, and generates a measurement signal in the time domain. Based on the trained long and short-term memory (LSTM) network, the signal of the next time step of the current time step measured by the vibration detection device is predicted. By combining the measurement signal and the prediction signal, a new combined signal with an increased length in the time domain is created. By Fourier transforming the combined signal, noise is reduced, and the information of the measurement signal is enhanced to obtain a signal in the frequency domain, which is then used to obtain a spectral density function to detect cracks in the structure.