Fatigue damage detection and growth monitoring for composite structure using coda wave interferometry

Abstract

Summary This paper presents the development of a fatigue damage detection and growth monitoring technique based on coda wave interferometry (CWI) for composite structures. The time domain distortion (TD) component of coda waves, which is typically ignored as noise in the literature, is used and experimentally validated. First, a widely used signal processing method for CWI called the stretching method is applied, and TD component is extracted in the time domain. Next, threshold values are statistically estimated using noise levels of the signal and compared with the amplitude of TD component for detecting early‐stage fatigue damage. A damage index (DI) is then obtained from TD component and used to monitor fatigue damage growth. The experimental results of the damage detection and growth monitoring are validated through visual inspection during the fatigue test. Finally, the developed technique's performance is evaluated by comparing it to conventional ultrasonic and CWI‐based composite fatigue damage assessment methods. The uniqueness of this study lies in (1) detection and growth monitoring of the early‐stage composite fatigue damage, (2) extraction and use of TD component of CWI and investigation of the correlation with the damage existence and growth, and (3) experimental validation and performance examination by comparing with the conventional ultrasonic and CWI‐based composite fatigue damage assessment methods.

Numerical Parametric Study of Coda Wave Interferometry Sensitivity to Microcrack Change in a Multiple Scattering Medium

“…For each fitted curve R 2 > 0.94, which indicates that the results of this quadratic regression are satisfactory. All fitted curves can be represented uniformly by Equation (10), where α θ Kd denotes the slope at θ.…”

“…In fact, the coda waves that are scattered several times are extremely sensitive to small changes inside complex media. Coda wave interferometry (CWI) is known as a highly sensitive method for small changes in heterogeneous media and has shown significant advantages in laboratory studies in the field of damage growth monitoring [7][8][9][10]. In laboratory experiments, experimental results for monitoring the crack propagation process in materials are influenced by a combination of factors such as external loads [11] and ambient temperature [12].…”

Diffuse Ultrasonic Wave-Based Damage Detection of Railway Tracks Using PZT/FBG Hybrid Sensing System

“…DUW is very sensitive to small changes in the medium since it propagates for longer propagation distance and interacts with scattering sources (defects) multiple times. Compared to the direct wave, the DUW received by the sensor is the superposition of waves from all directions, which leads to the wider sensing range [ 20 , 21 ]; on the other hand, multiple scattering events make the DUW sensitive to small perturbations of the materials [ 22 , 23 ].…”

“…DUW was first explored in geological engineering to identify slight changes of the earth’s crust by seismologists [ 24 ]. Recently, efforts have been made to apply DUW to damage detection and condition monitoring of concrete materials [ 25 , 26 , 27 ], composite structures [ 23 , 28 , 29 ], and metallic structures [ 30 , 31 ]. Liu et al [ 25 ] utilized DUW for self-healing process monitoring of concrete where biomineralization was used to repair internal cracks.…”

“…The results indicated that the relative velocity change of the DUW could reveal the strength development of the self-healing concrete. Lim et al [ 23 ] applied DUW to early-stage fatigue damage detection and crack growth monitoring of carbon-fiber-reinforced polymer (CFRP) composite plate. The results showed that time domain distortion of DUW signals could be used to assess fatigue damage of the CFRP plate.…”