A method to improve detection of release fabric in fiber reinforced composite by through transmission ultrasound
LeMay, Gary S. Kral, Zachary Tyler Boldsaikhan, Enkhsaikhan
LeMay, Gary S.
Kral, Zachary Tyler
Boldsaikhan, Enkhsaikhan
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2023
Type
Conference paper
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Keywords
Acoustic impedance,Contamination,Fast Fourier transforms,Fiber reinforced plastics,Fibers,Frequency domain analysis,Impurities,Inspection,Multilayers,Nondestructive examination,Ultrasonic testing,Attenuation,Confidence interval,Fibre-reinforced composite,In-fiber,Release fabric,Root Mean Square,Through transmission,Through transmission ultrasound,Transmission coefficients,Transmission ultrasounds,Defects
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Citation
LeMay, G.S., Kral, Z.T., Boldsaikhan, E. A METHOD TO IMPROVE DETECTION OF RELEASE FABRIC IN FIBER REINFORCED COMPOSITE BY THROUGH TRANSMISSION ULTRASOUND. (2023). Composites and Advanced Materials Expo, CAMX 2023. DOI: 10.33599/nasampe/c.23.0086
Abstract
Subsurface defect detection depends on several factors, such as the defect type, the defect location and geometry, the inspection method, the material to be inspected, impurities, and so on. Fiber Reinforced Composite (FRC) is a ply-by-ply manufacturing process that utilizes several materials such as, bagging film, breather/bleeder cloth, parting film, release fabric, and wire systems. Such materials can be inadvertently left inside the final product, categorized as foreign. Foreign materials lead to subsurface defects that can cause premature failure and must be detected with Nondestructive Inspection (NDI). Ultrasound NDI is an industry technique used for subsurface defect detection in FRC. Ultrasound NDI techniques are fundamentally based on acoustic impedance properties and time-based resolution. Certain applications require Through Transmission Ultrasound (TTU) - where sound is transmitted from one sensor and received by another. Received TTU signals are based on differences in amplitude, as defect detection relies on dissimilarities in signal strength compared to the defect free baseline. Changes in amplitude are a function of acoustic impedance by way of transmission coefficients. The acoustic impedance between certain foreign materials and baseline FRC are similar, resulting in minimal differences in signal strength, equally affecting detection. This study was conducted to develop a process to improve the detection of release fabric defects in FRC by TTU. The original signals comparing the baseline to the release fabric defect were associated in terms of peak amplitude, arithmetic mean, and standard deviation. The signals were converted from time to the frequency domain by Fast Fourier Transform (FFT). The root mean square (RMS) was then calculated based on the frequency components for comparison. Finally, confidence intervals were calculated to establish thresholds for both the amplitude and RMS values. The result is a method to improve detection of release fabric defects in FRC laminate by TTU. Other physical factors that affect foreign material detectability remain a field of study. Copyright © 2023. Used by CAMX - The Composites and Advanced Materials Expo with permission.
Table of Contents
Description
9th Annual Composites and Advanced Materials Expo, CAMX 2023
30 October 2023 through 2 November 2023
30 October 2023 through 2 November 2023
Publisher
The Composites and Advanced Materials Expo (CAMX)
Journal
Composites and Advanced Materials Expo, CAMX 2023