Application of Ultrasonic Coda Wave Interferometry for Micro-cracks Monitoring in Woven Fabric Composites

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited version published in: https://sam.ensam.eu Handle ID AbstractThe consequences of a four-point bending test, up to 12 mm, are examined by emitting 1 MHz ultrasonic guided waves in woven carbon fiber reinforced polymer specimens, using coda wave interferometry (CWI), revealing a potential use for nondestructive evaluation. It is known that CWI is more sensitive to realistic damage than the conventional method based on the first arriving time of flight in geophysical, or in civil engineering applications such as concrete structures. However, in composite materials CWI is not well established because of the involved structural complexity. In this paper, CWI is investigated for monitoring the occurrence of realistic defects such as micro-cracks in a woven carbon fiber composite plate.The micro-cracks are generated by a four-point bending test. The damage state is stepwise enhanced by gradually increasing the load level, until failure initiation. The damage is monitored, after each loading, using ultrasound. It is demonstrated that CWI is a powerful tool to detect damage, even low levels, in the sample. Two damage indicators based on CWI, i.e. signals correlation coefficient and relative velocity change, are investigated and appear to be complimentary. Under significant loading levels, the normalized cross-correlation coefficient between the waveforms recorded in the damaged and in the healthy sample (reference at 0 mm), decreases sharply; this first indicator is therefore useful for severe damage detection. It is also demonstrated, by means of a second indicator, that the relative velocity change between a baseline signal taken at zero loading, and the signals taken at various loadings, is linear as a function of the loading, until a critical level is reached; therefore this second indicator, is useful for low damage level detection. The obtained evolution of the relative velocity measurement is supported by relative comparison to the evolution of the bending modulus in function of displacement. The relative velocity change exhibits the same evolution as the bending modulus with loading. It could be used to indicate when the material stiffness has decreased significantly. The research is done in the framework of composite manufacturing quality control and appears to be a promising inspection technique.

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

“…In this section, the performance of the proposed fatigue damage assessment technique is compared with conventional methods used in previous studies, that is, (1) time lag of the first arrival, 14,15 (2) time lag of the coda waves, 16,21 (3) decorrelation coefficient of the first arrival, 16 and (4) decorrelation coefficient of the coda waves 20,25 . First, the time lag method was applied to the first arrival and the coda waves.…”

“…Consider s 0 [ t ] and s k [ t ] are the reference signal obtained from the intact condition of the structure, and the k th test signal acquired from an unknown state, respectively, the CC value can be obtained as follows: From the CC value calculation, two damage indices can be defined and used for the quantitative estimation of the coda wave variation. First, the time delay (time lag, δt ) between two signals is obtained by finding δt , which maximizes the CC value because more scattering of ultrasonic waves generally leads to increase of time lag 20 . The other index is the decorrelation coefficient using the maximum CC value 24,29 .…”

“…An ultrasonic wave that is introduced into a complex medium with multiple scatterers, such as micro defects, voids, and interfaces between heterogeneous materials, experiences a minimal amount of delay and attenuation owing to the scatterings. The ultrasonic wave response obtained from the medium can be separated into two parts: the first arrival, which consists of the waves that directly transmit along the path between the excitation and sensing locations, and the late part, which is composed of the scattered and reflected waves from the scatterers and structural boundaries 20 . Here, the waves in the late part (called “coda”) travel the longer path, and the weak changes induced by the interaction with the scatterers are accumulated more than the first arrival.…”

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

“…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.…”

Experimental Study of Defect Localization in a Cross-Ply Fiber Reinforced Composite with Diffuse Ultrasonic Waves

“…The sudden slope change of the PDI represents the stress state change from concentration to relaxation during defect generation. Recently, Pascal et al [31] applied coda wave interferometry to monitor micro crack propagation in a polypropylene sulfide based carbon fiber composite with a layering sequence of [0…”