scholarly journals Robust Polymer Planar Bragg Grating Sensors Embedded in Commercial-Grade Composites

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 715 ◽  
Author(s):  
Stefan Kefer ◽  
Theresia Sauer ◽  
Steffen Hessler ◽  
Michael Kaloudis ◽  
Bernhard Schmauss ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Bragg Grating ◽  
Bragg Wavelength ◽  
Commercial Grade ◽  
Plausibility Check ◽  
Reinforced Polymer ◽  
Mechanical Press ◽  
Cyclic Olefin Copolymers

This contribution demonstrates the functionality of polymer planar Bragg grating (PPBG) sensors integrated into commercial-grade carbon fiber reinforced polymer (CFRP) components. Multiple CFRP specimens are generated by curing a stack of pre-impregnated fibers inside of a heated mechanical press, exposing the polymer sensor to a pressure of 7 bar and a temperature of 120 °C for 2 h. After integration, the sensor still exhibits a strong and evaluable signal. Subsequent flexural experiments reveal a linear response of the integrated sensor’s Bragg wavelength to the CFRP specimen’s maximum deflection. Additional findings demonstrate that the embedded PPBG can be used to detect plastic deformations of a CFRP workpiece, whereas a linear correlation of plastic deformation to the resulting Bragg signal offset is determined. A plausibility check of the obtained results is delivered by a comparison of three-point flexural experiments on bulk CFRP workpieces, without integrated sensors and additional specimens featuring external optical sensors affixed to their surface. It is found that PPBGs based on cyclic olefin copolymers are able to overcome the temperature-related limitations of traditional polymer-based optical sensors and can thus be directly integrated into commercial-grade composites during production.

scholarly journals Influence of Humidity on Fiber Bragg Grating Sensors

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ander Montero ◽  
Gotzon Aldabaldetreku ◽  
Gaizka Durana ◽  
Iagoba Jorge ◽  
Idurre Sáez de Ocáriz ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Spot Welding ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Bragg Grating ◽  
Bragg Wavelength ◽  
Fiber Bragg Grating Sensors ◽  
Reinforced Polymer ◽  
Wide Range ◽  
Different Types

We demonstrate the influence of the relative humidity (RH) on the wavelength of fiber Bragg grating sensors (FBGS), performing tests with five FBGS at different humidity and temperature conditions. These tests were performed in a climate chamber whose RH changes according to a scheduled profile from 30% to 90%, in steps of 10%. These profiles were repeated for a wide range of temperatures from10∘Cto70∘C, in steps of10∘C. Two different types of instrumentation methods have been tested, spot welding and epoxy bonding, in two different materials, steel and carbon fiber reinforced polymer (CFRP). We discuss the results for each type of sensor and instrumentation method by analyzing the linearity of the Bragg wavelength with RH and temperature.

Experimental study on the mechanical and self-sensing behaviors of prestressed carbon fiber–reinforced polymer reinforced concrete composite structures

2020 ◽  
Vol 23 (8) ◽  
pp. 1507-1520
Author(s):  
Guan Wang ◽  
Caiqian Yang ◽  
Chunlin Meng ◽  
Zhenxue Xia ◽  
Yong Pan ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Fiber Bragg Grating ◽  
Composite Structures ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Bragg Grating ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

A type of self-sensing prestressed carbon fiber–reinforced polymer reinforced concrete composite structure was proposed and studied, composed of reinforced concrete beam, prestressed carbon fiber–reinforced polymer plate, and long-gauge fiber Bragg grating sensors. The carbon fiber–reinforced polymer plate was prestressed and bonded to the bottom of the reinforced concrete beam. Two types of anchorage systems were compared and studied. The long-gauge fiber Bragg grating sensors were used as active elements for the self-sensing of mechanical responses, which were installed on the tensile rebars, carbon fiber–reinforced polymer plates, and concrete. A series of static and fatigue 4-point flexural experiments were carried out to study the bending and fatigue performances of the composite structures. After a prescribed number of fatigue loading cycles, monotonic flexural bending was performed to investigate the deterioration of properties. The results showed that the long-gauge fiber Bragg grating sensor is valid for the mechanical response sensing of the proposed structures. The compatibility of the prestressed carbon fiber–reinforced polymer plate and concrete in the pure bending zone is excellent even under fatigue loading. The load-carrying capacities were improved by more than 30% due to the application of prestressed carbon fiber–reinforced polymer plates. The stiffness was also improved remarkably and generally decreased with the accumulation of fatigue cycles linearly.

scholarly journals A monitoring technique for disbond area in carbon fiber–reinforced polymer bonded joints using embedded fiber Bragg grating sensors: Development and experimental validation

2016 ◽  
Vol 16 (2) ◽  
pp. 185-201 ◽  
Author(s):  
Shigeki Yashiro ◽  
Jumpei Wada ◽  
Yoshihisa Sakaida
Keyword(s):  
Carbon Fiber ◽  
Fiber Bragg Grating ◽  
Intensity Ratio ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Bragg Grating ◽  
Peak Intensity Ratio ◽  
Fiber Bragg Grating Sensors ◽  
Reinforced Polymer ◽  
Peak Intensity

This study evaluated fatigue-induced disbond areas in carbon fiber–reinforced polymer double-lap joints using embedded fiber Bragg grating sensors. When the disbond grew by cyclic loading, the embedded fiber Bragg grating sensors yielded reflection spectra having two peaks representing a step-like strain distribution generated by the disbond; the peak at the shorter wavelength corresponded to the unloaded disbond region. The ratio of the peak intensity at the shorter wavelength to that at the longer wavelength increased gradually with increasing disbond length. The relationship between the peak intensity ratio and the disbond length was analyzed by coupled structural–optical analysis and was validated by comparing analytical peak intensity ratio with the experiment results. The disbond length was then estimated from the measured spectra based on this analytical calibration relationship, but the estimated disbond area exceeded that observed using the ultrasonic C-scan technique. Additional experiments including destructive observation of the adhesive suggested that an embedded fiber Bragg grating sensor could detect a moving disbond tip earlier than conventional nondestructive techniques.

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.

High thermal conductivity carbon fiber reinforced polymer based on a carbon fiber from pitch and dispersed-filled ENPB matrix

2018 ◽  
pp. 130-137
Author(s):  
E. A. Nikolaeva ◽  
A. N. Timofeev ◽  
K. V. Mikhaylovskiy
Keyword(s):  
Thermal Conductivity ◽  
Carbon Fiber ◽  
High Thermal Conductivity ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Carbon Powder ◽  
Fiber Reinforced ◽  
Thermophysical Characteristics ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

This article describes the results of the development of a high thermal conductivity carbon fiber reinforced polymer based on carbon fiber from pitch and an ENPB matrix modified with a carbon powder of high thermal conductivity. Data of the technological scheme of production and the results of determining the physicomechanical and thermophysical characteristics of carbon fiber reinforced polymer are presented. 

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