Investigation of optical fibers as sensors for condition monitoring of composite materials

1991 ◽  
Author(s):  
Peter L. Nielsen
Keyword(s):  
Composite Materials ◽  
Optical Fibers ◽  
Condition Monitoring

scholarly journals Damage detection in laminar thermoplastic composite materials by means of embedded optical fibers

2006 ◽  
Vol 60 (7-8) ◽  
pp. 176-179
Author(s):  
Aleksandar Kojovic ◽  
Irena Zivkovic ◽  
Ljiljana Brajovic ◽  
Dragan Mitrakovic ◽  
Radoslav Aleksic
Keyword(s):  
Composite Materials ◽  
Optical Fiber ◽  
Real Time ◽  
Optical Fibers ◽  
Impact Damage ◽  
Experimental Testing ◽  
Low Energy ◽  
Thermoplastic Composite ◽  
Woven Fabric ◽  
The Impact

This paper investigates the possibility of applying optical fibers as sensors for investigating low energy impact damage in laminar thermoplastic composite materials, in real time. Impact toughness testing by a Charpy impact pendulum with different loads was conducted in order to determine the method for comparative measurement of the resulting damage in the material. For that purpose intensity-based optical fibers were built in to specimens of composite materials with Kevlar 129 (the DuPont registered trade-mark for poly(p-phenylene terephthalamide)) woven fabric as reinforcement and thermoplastic PVB (poly(vinyl butyral)) as the matrix. In some specimens part of the layers of Kevlar was replaced with metal mesh (50% or 33% of the layers). Experimental testing was conducted in order to observe and analyze the response of the material under multiple low-energy impacts. Light from the light-emitting diode (LED) was launched to the embedded optical fiber and was propagated to the phototransistor-based photo detector. During each impact, the signal level, which is proportional to the light intensity in the optical fiber, drops and then slowly recovers. The obtained signals were analyzed to determine the appropriate method for real time damage monitoring. The major part of the damage occurs during impact. The damage reflects as a local, temporary release of strain in the optical fiber and an increase of the signal level. The obtained results show that intensity-based optical fibers could be used for measuring the damage in laminar thermoplastic composite materials. The acquired optical fiber signals depend on the type of material, but the same set of rules (relatively different, depending on the type of material) could be specified. Using real time measurement of the signal during impact and appropriate analysis enables quantitative evaluation of the impact damage in the material. Existing methods in most cases use just the intensity of the signal before and after the impact, as the measure of damage. This method could be used to monitor the damage in real time, giving warnings before fatal damage occurs.

Integration of optical fibers and piezoelectric ceramics in composite materials

1996 ◽  
Author(s):  
S. Bourasseau ◽  
Marc Dupont ◽  
M. Pernice ◽  
Alain Thiriot ◽  
P. Blanquet ◽  
...  
Keyword(s):  
Composite Materials ◽  
Optical Fibers ◽  
Piezoelectric Ceramics

Damage Classification of Composites Using Machine Learning

2019 ◽  
Author(s):  
Shweta Dabetwar ◽  
Stephen Ekwaro-Osire ◽  
João Paulo Dias
Keyword(s):  
Machine Learning ◽  
Composite Materials ◽  
Random Forest ◽  
Condition Monitoring ◽  
Machine Learning Algorithms ◽  
Support Vector ◽  
Damage Classification ◽  
Combining Data ◽  
Ultrasonic Measurements

Abstract Composite materials have tremendous and ever-increasing applications in complex engineering systems; thus, it is important to develop non-destructive and efficient condition monitoring methods to improve damage prediction, thereby avoiding catastrophic failures and reducing standby time. Nondestructive condition monitoring techniques when combined with machine learning applications can contribute towards the stated improvements. Thus, the research question taken into consideration for this paper is “Can machine learning techniques provide efficient damage classification of composite materials to improve condition monitoring using features extracted from acousto-ultrasonic measurements?” In order to answer this question, acoustic-ultrasonic signals in Carbon Fiber Reinforced Polymer (CFRP) composites for distinct damage levels were taken from NASA Ames prognostics data repository. Statistical condition indicators of the signals were used as features to train and test four traditional machine learning algorithms such as K-nearest neighbors, support vector machine, Decision Tree and Random Forest, and their performance was compared and discussed. Results showed higher accuracy for Random Forest with a strong dependency on the feature extraction/selection techniques employed. By combining data analysis from acoustic-ultrasonic measurements in composite materials with machine learning tools, this work contributes to the development of intelligent damage classification algorithms that can be applied to advanced online diagnostics and health management strategies of composite materials, operating under more complex working conditions.

Laminar Composite Materials Damage Monitoring by Embedded Optical Fibers

2008 ◽  
pp. 1035-1036 ◽  
Author(s):  
Aleksandar Kojovi ◽  
Zivkovi Irena ◽  
Ljiljana Brajovi ◽  
Dragan Mitrakovi ◽  
Radoslav Aleksi
Keyword(s):  
Composite Materials ◽  
Optical Fibers ◽  
Laminar Composite ◽  
Damage Monitoring

scholarly journals Polymer Fibers Covered by Soft Multilayered Films for Sensing Applications in Composite Materials

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 4052 ◽  
Author(s):  
Dorian Nikoniuk ◽  
Karolina Bednarska ◽  
Maksymilian Sienkiewicz ◽  
Grzegorz Krzesiński ◽  
Mateusz Olszyna ◽  
...  
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Optical Fibers ◽  
Temperature Sensitivity ◽  
Polymer Coating ◽  
Layer By Layer ◽  
Sensor Applications ◽  
Sensing Applications ◽  
Polymer Optical Fibers ◽  
Soft Polymer

This paper presents the possibility of applying a soft polymer coating by means of a layer-by-layer (LbL) technique to highly birefringent polymer optical fibers designed for laminating in composite materials. In contrast to optical fibers made of pure silica glass, polymer optical fibers are manufactured without a soft polymer coating. In typical sensor applications, the absence of a buffer coating is an advantage. However, highly birefringent polymer optical fibers laminated in a composite material are much more sensitive to temperature changes than polymer optical fibers in a free space as a result of the thermal expansion of the composite material. To prevent this, we have covered highly birefringent polymer optical fibers with a soft polymer coating of different thickness and measured the temperature sensitivity of each solution. The results obtained show that the undesired temperature sensitivity of the laminated optical fiber decreases as the thickness of the coating layer increases.

Highly birefringent polymer microstructured optical fibers embedded in composite materials

2013 ◽  
Author(s):  
P. Lesiak ◽  
M. Szeląg ◽  
M. Kuczkowski ◽  
A. W. Domański ◽  
T. R. Woliński
Keyword(s):  
Composite Materials ◽  
Optical Fibers ◽  
Microstructured Optical Fibers

Strain measurement and cure monitoring in thin plates of composite materials by using twisted optical fibers

1996 ◽  
Author(s):  
Huiwen Wang ◽  
Jan Wu ◽  
Naiji Li ◽  
Hongjun Cao ◽  
Di Dai ◽  
...  
Keyword(s):  
Composite Materials ◽  
Optical Fibers ◽  
Strain Measurement ◽  
Thin Plates ◽  
Cure Monitoring
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