Ultra-violet health monitoring of smart composite laminate using embedded fiber Bragg grating sensors

2020 ◽  
Vol 54 (22) ◽  
pp. 3143-3158 ◽  
Author(s):  
S Mohanta ◽  
Y Padarthi ◽  
S Chokkapu ◽  
J Gupta ◽  
S Neogi

A novel approach is developed to evaluate the property retention on prolonged ultra-violet exposure and hence, health monitoring of glass fiber reinforced polymer composite laminate. This is achieved in a non-destructive manner by mapping the strength retention with the established strain. Embedded fiber Bragg grating sensor and strain gauges are employed to monitor the strain evolution within the laminate. Tensile and flexural tests are conducted at regular intervals to estimate the mechanical strength retention with varying duration of ultra-violet exposure. Through this analysis, it is observed that the property degradation mechanism follows the first-order reaction kinetics. The degradation of matrix material along with the stress relaxation over time develops the stress–strain fields near the interfaces of matrix and fiber. Moreover, the established strain is interpreted by formulating the model that considers the unifying influence of stress relaxation and chemical degradation. This model has closely (R2 = 0.9810 and 0.9790) predicted the experimental data of strain than the existing ones (R2 = 0.9142 and 0.9119). Besides, property retention is mapped with the predicted strain. More importantly, FESEM and FTIR confirm the fact that ultra-violet radiation degrades the matrix material, and thus the mechanical property gets significantly deteriorated. This suggests that the strain measurement is an effective, non-destructive and health monitoring technique to assess the property degradation of the manufactured glass fiber reinforced polymer composites.

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Weiwen Li ◽  
Chunyang Ji ◽  
Honggang Zhu ◽  
Feng Xing ◽  
Jiaxin Wu ◽  
...  

Nanoclay layers incorporated into polymer/clay nanocomposites can inhibit the harmful penetration of water and chemicals into the material, and thus the durability of glass fiber-reinforced polymer (GFRP) composites should be enhanced by using polymer/clay nanocomposite as the matrix material. In this study, 1.5 wt% vinyl ester (VE)/organoclay and 2 wt% epoxy (EP)/organoclay nanocomposites were prepared by an in situ polymerization method. The dispersion states of clay in the nanocomposites were studied by performing XRD analysis. GFRP composites were then fabricated with the prepared 1.5 wt% VE/clay and 2.0 wt% EP/clay nanocomposites to investigate the effects of a nanocomposite matrix on the durability of GFRP composites. The durability of the two kinds of GFRP composites was characterized by monitoring tensile properties following degradation of GFRP specimens aged in water and alkaline solution at 60°C, and SEM was employed to study fracture behaviors of aged GFRP composites under tension. The results show that tensile properties of the two types of GFRP composites with and without clay degrade significantly with aging time. However, the GFRP composites with nanoclay show a lower degradation rate compared with those without nanoclay, supporting the aforementioned hypothesis. And the modification of EP/GFRP enhanced the durability more effectively.


2018 ◽  
Vol 52 (21) ◽  
pp. 2929-2948 ◽  
Author(s):  
Ahmed H Ali ◽  
Brahim Benmokrane ◽  
Hamdy M Mohamed ◽  
Allan Manalo ◽  
Adel El-Safty

This paper presents experimental investigation, statistical analysis, and theoretical predictions of tensile-strength retention of glass fiber-reinforced polymer bars, made with vinyl-ester, polyester, or epoxy resins. The durability of glass fiber-reinforced polymer bars was evaluated as a function of time of immersion in alkaline solution. The aging of the three glass fiber-reinforced polymer bar types consisted of immersion glass fiber-reinforced polymer bar samples in an alkaline solution (up to 5000 h) at different elevated exposure temperatures. Subsequently, the physical and tensile properties of the unconditioned bars were compared with that of the conditioned bars to assess the durability performance of the glass fiber-reinforced polymer bars. Microstructure of all of the glass fiber-reinforced polymer bar types was investigated with scanning electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy for both the conditioned and unconditioned cases, to qualitatively explain the experimental results and to assess changes and/or degradation in the glass fiber-reinforced polymer bars. In addition, the long-term performance of glass fiber-reinforced polymer bars was assessed considering the effect of service years, environmental humidity, and seasonal temperature fluctuations. The test results showed that the tensile strength of the glass fiber-reinforced polymer bars was affected by increased immersion time at higher temperatures and the reduction in tensile strength was statistically significantly dependent on the type of resin system. The prediction approach of the glass fiber-reinforced polymer bars based on the environmental reduction factor ( CE) after 200 years indicated that the CE values for vinyl-ester, epoxy, and polyester glass fiber-reinforced polymer bars can be conservatively recommended to 0.81, 0.75, and 0.71, respectively, for a moisture-saturated environment (relative humidity = 100%) and at 30℃. The polyester glass fiber-reinforced polymer bars experienced greater debonding at the fiber–resin interface than the vinyl-ester and epoxy glass fiber-reinforced polymer bars.


2021 ◽  
Vol 5 (9) ◽  
pp. 238
Author(s):  
Zhiqiang Han ◽  
Jaewon Jang ◽  
Sang-Gyu Lee ◽  
Dongkun Lee ◽  
Daekyun Oh

Glass fiber-reinforced polymer (GFRP) ship structures are generally fabricated by hand lay-up; thus, the environmental factors and worker proficiency influence the fabrication process and presence of error in the non-destructive evaluation results. In this study, the ultrasonic testing of GFRP hull plate prototypes was conducted to investigate the statistical significance of the influences of the design parameters, e.g., the glass fiber weight fraction (Gc) and thickness variations, on the measurement error. The GFRP hull plate prototypes were fitted with E-glass fiber chopped strand mats (40 wt % content) with different thicknesses (7.72 mm, 14.63 mm, and 18.24 mm). The errors in the thickness measurements were investigated by conducting pulse-echo ultrasonic A-scan. The thickness variation resulted in increased error. Furthermore, hull plate burn-off tests were conducted to investigate the fabrication qualities. Defects such as voids did not have a significant influence on the results. The statistical analysis of the measurement errors confirmed that the thickness variations resulted in a strong ultrasonic interference between the hull plates, although the hull plates had similar specific gravity values. Therefore, the ultrasonic interference of the layer group interface should be considered to decrease the GFRP hull NDE errors with respect to an increase in the thickness and Gc.


Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 16
Author(s):  
Gabriel Mansour ◽  
Panagiotis Kyratsis ◽  
Apostolos Korlos ◽  
Dimitrios Tzetzis

There are numerous engineering applications where Glass Fiber Reinforced Polymer (GFRP) composite tubes are utilized, such as desalination plants, power transmission systems, and paper mill, as well as marine, industries. Some type of machining is required for those various applications either for joining or fitting procedures. Machining of GFRP has certain difficulties that may damage the tube itself because of fiber delamination and pull out, as well as matrix deboning. Additionally, short machining tool life may be encountered while the formation of powder like chips maybe relatively hazardous. The present paper investigates the effect of process parameters for surface roughness of glass fiber-reinforced polymer composite pipes manufactured using the filament winding process. Experiments were conducted based on the high-speed turning Computer Numerical Control (CNC) machine using Poly-Crystalline Diamond (PCD) tool. The process parameters considered were cutting speed, feed, and depth of cut. Mathematical models for the surface roughness were developed based on the experimental results, and Analysis of Variance (ANOVA) has been performed with a confidence level of 95% for validation of the models.


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