scholarly journals Data Enhancement via Low-Rank Matrix Reconstruction in Pulsed Thermography for Carbon-fiber-Reinforced Polymers

Author(s):  
Samira Ebrahimi ◽  
Julien R Fleuret ◽  
Matthieu Klein ◽  
Louis-Daniel Théroux ◽  
Clemente Ibarra-Castanedo ◽  
...  

Pulsed thermography is a commonly used non-destructive testing method, and is increasingly studied for advanced materials such as carbon fiber-reinforced polymer (CFRP) evaluation. Different processing approaches are proposed to detect and characterize anomalies that may be generated in structures during the manufacturing cycle or service period. In this study, we used a type of matrix decomposition using Robust-PCA via Inexact-ALM in our experiment. We investigate this method as a pre-and post-processing method on thermal data acquired by pulsed thermography. We employed state-of-the-art methods, i.e., PCT, PPT, and PLST, as the main process. The results indicate that pre-processing on thermal data can elevate the defect detectability while post-processing, in some cases, can deteriorate the results.

2021 ◽  
Vol 11 (4) ◽  
pp. 1508
Author(s):  
Muhammad Khalid Rizwan ◽  
Stefano Laureti ◽  
Hubert Mooshofer ◽  
Matthias Goldammer ◽  
Marco Ricci

The use of pulse-compression in ultrasonic non-destructive testing has assured, in various applications, a significant improvement in the signal-to-noise ratio. In this work, the technique is combined with linear phased array to improve the sensitivity and resolution in the ultrasonic imaging of highly attenuating and scattering materials. A series of tests were conducted on a 60 mm thick carbon fiber reinforced polymer benchmark sample with known defects using a custom-made pulse-compression-based phased array system. Sector scan and total focusing method images of the sample were obtained with the developed system and were compared with those reconstructed by using a commercial pulse-echo phased array system. While an almost identical sensitivity was found in the near field, the pulse-compression-based system surpassed the standard one in the far-field producing a more accurate imaging of the deepest defects and of the backwall of the sample.


2011 ◽  
Vol 343-344 ◽  
pp. 142-149 ◽  
Author(s):  
Jian Shi ◽  
Kiyoshi Kemmochi ◽  
Li Min Bao

The objective of the present study is to investigate the effect of pyrolysis time and temperature on the mechanical properties of recycled carbon fiber, based on tensile strength measurements, determining the optimum decomposition conditions for carbon fiber-reinforced polymers (CFRPs) by superheated steam. In this research, CFRPs were efficiently depolymerized and reinforced fibers were separated from resin by superheated steam. Tensile strength of fibrous recyclates was measured and compared to that of virgin fiber. Although tensile strength of recycled fibers were litter lower than that of virgin fiber, under some conditions tensile strength of recycled fibers were close to that of virgin fiber. With pyrolysis, some char residue from the polymer remains on the fibers and degrees of char on the recycled fibers were closely examined by scanning electron microscopy.


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