Reconstruction of cracks in a carbon fiber-reinforced polymer laminate plate from signals of eddy current testing

2020 ◽  
Vol 54 (24) ◽  
pp. 3527-3536
Author(s):  
Yali Du ◽  
Xudong Li ◽  
Shejuan Xie ◽  
Shiyou Yang ◽  
Zhenmao Chen
Keyword(s):  
Carbon Fiber ◽  
Eddy Current ◽  
Inverse Analysis ◽  
Eddy Current Testing ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Current Testing ◽  
Reinforced Polymer ◽  
Cfrp Plate

This article aims to study the quantitative eddy current testing of structures of carbon fiber reinforced polymer (CFRP) material; numerical schemes for forward and inverse analysis of eddy current testing signals are proposed and validated for eddy current testing of the CFRP material. At first, an efficient forward solver based on the database approach is updated to treat anisotropic eddy current problem for efficient simulation of the eddy current testing signals due to crack in CFRP material, and an inversion scheme based on the conjugate gradient method is developed using the updated fast forward solver for sizing defect in a CFRP plate. Second, a hybrid inverse analysis scheme is proposed and implemented to improve the sizing accuracy of crack in a CFRP plate using eddy current testing signals of high frequency. Third, eddy current testing signals due to artificial cracks in a CFRP plate are measured and adopted to reconstruct the profile of the cracks. A good agreement between the true and the reconstructed defect sizes demonstrated the validity of both the fast forward solver and the new inversion scheme for sizing defects in the CFRP plate from eddy current testing signals.

scholarly journals Characteristics of Eddy Current Distribution in Carbon Fiber Reinforced Polymer

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Shaoni Jiao ◽  
Jian Li ◽  
Fei Du ◽  
Lei Sun ◽  
Zhiwei Zeng
Keyword(s):  
Carbon Fiber ◽  
Eddy Current ◽  
Fiber Reinforced Polymer ◽  
Electrical Anisotropy ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The paper studies the characteristics of eddy current (EC) distribution in carbon fiber reinforced polymer (CFRP) laminates so as to guide the research and operation of eddy current testing of CFRP. To this end, an electromagnetic field computation model of EC response to CFRP based on the finite element method is developed. Quantitative analysis of EC distribution in plies of unidirectional CFRP reveals that EC changes slowly along the fiber direction due to the strong electrical anisotropy of the material. Variation of EC in plies of multidirectional CFRP is fast in both directions. The attenuation of EC in the normal direction in unidirectional CFRP is faster than that in isotropic material due to faster diffusion of EC. In multidirectional CFRP, EC increases near the interfaces of plies having different fiber orientations. The simulation results are beneficial to optimizing sensor design and testing parameters, as well as damage detection and evaluation.

scholarly journals Flexural Strength of Carbon Fiber Reinforced Polymer Repaired Cracked Rectangular Hollow Section Steel Beams

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Tao Chen ◽  
Ming Qi ◽  
Xiang-Lin Gu ◽  
Qian-Qian Yu
Keyword(s):  
Carbon Fiber ◽  
Initial Crack ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Steel Beams ◽  
Fiber Reinforced ◽  
Hollow Section ◽  
Failure Patterns ◽  
Reinforced Polymer ◽  
Cfrp Plate

The flexural behavior of rectangular hollow section (RHS) steel beams with initial crack strengthened externally with carbon fiber reinforced polymer (CFRP) plates was studied. Eight specimens were tested under three-point loading to failure. The experimental program included three beams as control specimens and five beams strengthened with CFRP plates with or without prestressing. The load deflection curves were graphed and failure patterns were observed. The yield loads and ultimate loads with or without repairing were compared together with the strain distributions of the CFRP plate. It was concluded that yield loads of cracked beams could be enhanced with repairing. Meanwhile, the ultimate loads were increased to some extent. The effect of repair became significant with the increase of the initial crack depth. The failure patterns of the repaired specimens were similar to those of the control ones. Mechanical clamping at the CFRP plate ends was necessary to avoid premature peeling between the CFRP plate and the steel beam. The stress levels in CFRP plates were relatively low during the tests. The use of prestressing could improve the utilization efficiency of CFRP plates. It could be concluded that the patching repair could be used to restore the load bearing capacity of the deficient steel beams.

Delamination and hole wall roughness evaluation in air-cooled drilling of carbon fiber-reinforced polymer

2021 ◽  
pp. 002199832110092
Author(s):  
Nícholas Hoffmann ◽  
Gabriel SC Souza ◽  
André J Souza ◽  
Volnei Tita
Keyword(s):  
Carbon Fiber ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Process Time ◽  
Air Cooling ◽  
Wall Roughness ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Cfrp Plate ◽  
Carbon Fiber Reinforced

Drilling of carbon fiber-reinforced polymer (CFRP) is widely employed in manufacturing processes in the aeronautical, automobile, and energy industries. The evaluation of the hole region focusing on wall roughness and delamination phenomena is extremely important to predict bolted joints' performance, where at least one of the adherent is a composite material. Thus, this work performed a statistical analysis on the delamination (entrance and exit of the plate) and wall roughness of drilling holes in an 8.6 mm thick CFRP plate carried out by an uncoated carbide drill under compressed air-cooling, varying the cutting speeds and feed rates. Since air-cooling usage combines positive aspects, such as low-cost implementation and shorter process time compared to ultrasonic-assisted drilling, it turns out to be an excellent alternative for aeronautical industry. Thus, the main contribution of the present work consists on analyzing the variation of the delamination in the entrance and exit of the first and tenth holes of a CFRP plate after dry and air-cooled drilling. This variation of the delamination between the cold drill (first hole) and the heated drill due to the drilling holes' sequence (after ten holes) is investigated for 18 different combinations of parameters (runs). For instance, it is shown that if the combination of parameters values is suitable, then it is possible to reduce the mean value of adjusted delamination factor for the entrance of the tenth hole around 11% when comparing cooled-air with dry cutting.

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