关键词: 损伤识别, 疲劳裂纹, 高频频响函数, 非线性损伤

Abstract: Aiming at the traditional structural health monitoring method using linear frequency response function which relied on the comparing with the undamaged structures and limited the application scopes, a fatigue crack damage identification method without a reference signatures of the undamaged structures based on nonlinear high-frequency response function. By considering the nonlinear natures of damage structures, this paper suggested to make use of the theory that the forced frequency response function of the cracked beams varied when the beams were excited at different amplitude excitation to extract nonlinear components without reference to form damage index to characterize nonlinear damages. Sensitivity of different frequency bands to detect fatigue cracks was also analyzed herein. The implemented experiments testify that this method may effectively identify fatigue cracks without a reference signature.

Key words: damage detection, fatigue crack, high-frequency response function, nonlinear damage