scholarly journals Visual classification of braided and woven fiber bundles in X-ray computed tomography scanned carbon fiber reinforced polymer specimens

2016 ◽  
Vol 6 ◽  
pp. 39-46 ◽  
Author(s):  
Johannes Weissenböck ◽  
Arindam Bhattacharya ◽  
Bernhard Plank ◽  
Christoph Heinzl ◽  
Johann Kastner
Keyword(s):  
Computed Tomography ◽  
Carbon Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Bundles ◽  
Carbon Fiber Reinforced Polymer ◽  
Visual Classification ◽  
X Ray ◽  
Reinforced Polymer ◽  
X Ray Computed

scholarly journals Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates

2020 ◽  
Vol 54 (27) ◽  
pp. 4325-4337 ◽  
Author(s):  
Janez Rus ◽  
Alex Gustschin ◽  
Hubert Mooshofer ◽  
Jan-Carl Grager ◽  
Klaas Bente ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Dark Field ◽  
Piezoelectric Transducers ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
X Ray ◽  
Reinforced Polymer ◽  
Non Destructive ◽  
Ultrasound Testing ◽  
Destructive Methods

In the rapidly expanding composite industry, novel inspection methods have been developed in recent years. Particularly promising for air-coupled testing are cellular polypropylene transducers which offer better impedance matching to air than piezoelectric transducers. Furthermore, broadband transmitters (laser-induced ultrasound and thermoacoustic emitters) and receivers (optical microphones) have opened a completely new chapter for advanced contact-free ultrasound inspection. X-ray dark-field radiography offers a different approach to detect porosity and microcracks, employing small angle X-ray scattering. These innovative ultrasonic and radiographic alternatives were evaluated in comparison with well-established inspection techniques. We applied thirteen different non-destructive methods to inspect the same specimen (a carbon fiber-reinforced polymer laminate with induced impact damage): air-coupled ultrasound testing (using piezoelectric transducers, broadband optical microphones, cellular polypropylene transducers, and a thermoacoustic emitter), laser-induced ultrasound testing, ultrasonic immersion testing, phased array ultrasonic testing, optically excited lock-in thermography, and X-ray radiography (projectional absorption and dark-field, tomosynthesis, and micro-computed tomography). The inspection methods were qualitatively characterized by comparing the scan results. The conclusions are advantageous for a decision on the optimal method for certain testing constraints.

Fracture toughness enhancement of carbon fiber–reinforced polymer composites utilizing additive manufacturing fabrication

2018 ◽  
Vol 51 (7-8) ◽  
pp. 698-711 ◽  
Author(s):  
Firas Akasheh ◽  
Heshmat Aglan
Keyword(s):  
Carbon Fiber ◽  
Polymer Composites ◽  
Fracture Resistance ◽  
Fiber Reinforced Polymer ◽  
Fiber Bundles ◽  
Carbon Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
The Matrix ◽  
Carbon Fiber Bundles

The present work reports a novel approach to enhance the fracture resistance and notch sensitivity of carbon fiber-reinforced polymer composites utilizing additive manufacturing (3-D printing) fabrication. The 3-D printed composites utilize carbon fiber bundles to reinforce nylon/chopped fiber resin in a multilayered structure configuration. Single-edge (60°) notched samples were printed using Mark Two printer. Three reinforcement schemes were designed and used to manufacture the specimens. The focus was placed on selective reinforcement at the crack tip to arrest crack initiation. The mechanical properties, fracture toughness, and fracture behavior of the printed composites were evaluated. It was found that wrapping fiber around the notch effectively blunted the notch and redirected crack propagation away from the notch tip, thereby lengthening the crack path and leading to improved fracture resistance. It was also found that such improvement reaches a saturation level. Excessive notch reinforcement beyond optimal limit can reverse the gains in fracture resistance due to notch-targeted reinforcement. Examination of the fracture surface morphology of the printed composites reveals lack of fusion of the sizing of the individual continuous carbon fiber bundles and the lack of adhesion between the matrix layers (nylon/chopped fiber resin) and the adjacent carbon fiber bundle reinforcement. Damage to the fibers within the carbon bundle was also observed. Thus, a synergetic effect of the carbon fiber bundles reinforcement and the matrix requires more optimization to manufacture carbon-reinforced polymer composites using 3-D printing.

X-ray micro-computed tomography analysis of impact damage morphology in composite sandwich structures due to cold temperature arctic condition

2018 ◽  
Vol 52 (25) ◽  
pp. 3509-3522 ◽  
Author(s):  
MH Khan ◽  
Mohammed Elamin ◽  
Bing Li ◽  
KT Tan
Keyword(s):  
Computed Tomography ◽  
Low Temperature ◽  
Impact Damage ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Foam Core ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Reinforced Polymer ◽  
The Impact

In this study, X-ray micro-computed tomography is employed to characterize the impact damage mechanisms in foam core sandwiched composites, paying particular attention to the influence of extreme low temperature effects. Investigation on impact response reveals that more energy absorption with lower impact damage force occurs at lower temperature. Results evidently show that test temperature has a significant influence on the impact damage behavior. Post-mortem inspection portrays clear relationships between damages in both foam core and carbon fiber reinforced polymer facesheets, as well as exposed test temperature. Specimens impacted at extreme low temperature (−70℃) exhibit less strength, and higher susceptibility to damage, verified by severer penetration of the impactor. Micro-computed tomography is exploited to examine cross-sectional views of the impacted specimens, showing detailed damage mechanisms of the carbon fiber-reinforced polymer facesheets and the foam core, thereby evidently revealing multiple complex impact damage modes such as fiber breakage, delamination, core shearing and crushing, facesheet-core debonding, which are all strongly influenced by arctic low temperature. The findings of this work will lead to improved design for advanced composite structures with enhanced impact resistance and damage tolerance in extreme cold environment particularly in the arctic region.

Restoring Initially Cracked Reinforced Concrete Beams utilizing Carbon Fiber Reinforced Polymer Strips

2019 ◽  
Vol 7 (1) ◽  
pp. 30-34
Author(s):  
A. Ajwad ◽  
U. Ilyas ◽  
N. Khadim ◽  
Abdullah ◽  
M.U. Rashid ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Loading Test ◽  
Control Beam ◽  
Reinforced Polymer ◽  
Cfrp Sheet ◽  
Carbon Fiber Reinforced

Carbon fiber reinforced polymer (CFRP) strips are widely used all over the globe as a repair and strengthening material for concrete elements. This paper looks at comparison of numerous methods to rehabilitate concrete beams with the use of CFRP sheet strips. This research work consists of 4 under-reinforced, properly cured RCC beams under two point loading test. One beam was loaded till failure, which was considered the control beam for comparison. Other 3 beams were load till the appearance of initial crack, which normally occurred at third-quarters of failure load and then repaired with different ratios and design of CFRP sheet strips. Afterwards, the repaired beams were loaded again till failure and the results were compared with control beam. Deflections and ultimate load were noted for all concrete beams. It was found out the use of CFRP sheet strips did increase the maximum load bearing capacity of cracked beams, although their behavior was more brittle as compared with control beam.

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