scholarly journals Defect Detection in Composite Products Based on Sparse Moving Window Principal Component Thermography

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jing Jie ◽  
Shiqing Dai ◽  
Beiping Hou ◽  
Miao Zhang ◽  
Le Zhou
Keyword(s):  
Defect Detection ◽  
Principal Component ◽  
Thermal Image ◽  
Moving Window ◽  
Detection Experiment ◽  
Pulsed Thermography ◽  
Detection Range ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Free Region

As a nondestructive testing (NDT) technology, pulsed thermography (PT) has been widely used in the defect detection of the composite products due to its efficiency and large detection range. To enhance the distinction between defective and defect-free region and eliminate the influence of the measurement noise and nonuniform background of the thermal image generated by PT, a number of thermographic data analysis approaches have been proposed. However, these traditional methods only consider the correlations among the pixel while leave the time series correlations unmodeled. In this paper, a sparse moving window principal component thermography (SMWPCT) method is proposed to incorporate several thermal images using the moving window strategy. Also, the sparse trick is used to provide clearer and more interpretable results because of the structure sparsity. The effectiveness of the method is verified by the defect detection experiment of carbon fiber-reinforced plastic specimens.

scholarly journals Independent Component Analysis Applied on Pulsed Thermographic Data for Carbon Fiber Reinforced Plastic Inspection: A Comparative Study

2021 ◽  
Vol 11 (10) ◽  
pp. 4377
Author(s):  
Julien R. Fleuret ◽  
Samira Ebrahimi ◽  
Clemente Ibarra-Castanedo ◽  
Xavier P. V. Maldague
Keyword(s):  
Independent Component Analysis ◽  
State Of The Art ◽  
Great Influence ◽  
Principal Component ◽  
Component Analysis ◽  
Independent Component ◽  
Pulsed Thermography ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Reduction Methods

Dimensional reduction methods have significantly improved the simplification of Pulsed Thermography (PT) data while improving the accuracy of the results. Such approaches reduce the quantity of data to analyze and improve the contrast of the main defects in the samples contributed to their popularity. Many works have been proposed in the literature mainly based on improving the Principal Component Thermography (PCT). Recently the Independent Component Analysis (ICA) has been a topic of attention. Many different approaches have been proposed in the literature to solve the ICA. In this paper, we investigated several recent ICA methods and evaluated their influence on PT data compared with the state-of-the-art methods. We conducted our evaluation on reference CFRP samples with known defects. We found that ICA outperform PCT for small and deep defects. For other defects ICA results are often not far from the results obtained by PCT. However, the frequency of acquisition and the ICA methods have a great influence on the results.

Experimental Response of RC Beams Strengthened in Shear by FRP Sheets

2013 ◽  
Vol 7 (1) ◽  
pp. 127-135 ◽  
Author(s):  
E. Grande ◽  
M. Imbimbo ◽  
A. Rasulo
Keyword(s):  
Slenderness Ratio ◽  
Shear Capacity ◽  
Rc Beams ◽  
Fiber Reinforced Plastic ◽  
Frp Composites ◽  
Reinforced Plastic ◽  
Externally Bonded ◽  
Experimental Response ◽  
Transverse Steel ◽  
Cracking Pattern

The paper discusses the results of an experimental investigation carried out on reinforced concrete (RC) beams strengthened in shear by externally bonded fiber reinforced plastic (FRP) sheets. The study is devoted to analyze the role that the transverse steel reinforcement and the beam slenderness ratio could play on the resistant mechanism of RC beams strengthened in shear by FRP composites. The results are summarized and analyzed in detail in the paper in terms of shear capacity, cracking pattern and shear resisting contribution of FRP.

scholarly journals Stressing State Analysis of Reinforced Concrete Beam Strengthened by CFRP Sheet with Anchoring Device

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 576
Author(s):  
Liang Luo ◽  
Jie Lai ◽  
Jun Shi ◽  
Guorui Sun ◽  
Jie Huang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Strain Distribution ◽  
Carbon Fiber Reinforced Plastic ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Strain Distribution Pattern ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Cfrp Sheet ◽  
Carbon Fiber Reinforced

This paper investigates the working performance of reinforcement concrete (RC) beams strengthened by Carbon-Fiber-Reinforced Plastic (CFRP) with different anchoring under bending moment, based on the structural stressing state theory. The measured strain values of concrete and Carbon-Fiber-Reinforced Plastic (CFRP) sheet are modeled as generalized strain energy density (GSED), to characterize the RC beams’ stressing state. Then the Mann–Kendall (M–K) criterion is applied to distinguish the characteristic loads of structural stressing state from the curve, updating the definition of structural failure load. In addition, for tested specimens with middle anchorage and end anchorage, the torsion applied on the anchoring device and the deformation width of anchoring device are respectively set parameters to analyze their effects on the reinforcement performance of CFRP sheet through comparing the strain distribution pattern of CFRP. Finally, in order to further explore the strain distribution of the cross-section and analyze the stressing-state characteristics of the RC beam, the numerical shape function (NSF) method is proposed to reasonably expand the limited strain data. The research results provide a new angle of view to conduct structural analysis and a reference to the improvement of reinforcement effect of CFRP.

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