scholarly journals Investigation of Insulation Characteristics of GFRP Crossarm Subjected to Lightning Transient

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4386
Author(s):  
Muhammad Syahmi Abd Rahman ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Muhamad Safwan Abd Rahman ◽  
Miszaina Osman ◽  
Shamsul Fahmi Mohd Nor ◽  
...  

The advancement of material technology has contributed to the variation of high-performance composites with good electrical insulation and mechanical properties. Their usage in electrical applications has grown since then. In Malaysia, the composite made of Glass Fiber Reinforced Polymer (GFRP) has been adopted for crossarm manufacturing and has successfully served 275 kV lines for a few decades. However, the combination of extreme conditions such as lightning transient and tropical climate can impose threats to the material. These issues have become major topics of discussion among the utilities in the Southeast Asian (SEA) region, and also in previous research. In Malaysia, more than 50% of total interruptions were caused by lightning. Limited studies can be found on the composite crossarm, especially on the square tube GFRP filled crossarm used in Malaysia. Therefore, this paper proposes to study the behavior of the particular GFRP crossarm, by means of its insulation characteristics. Experimental and simulation approaches are used. Throughout the study, the GFRP specimen is known to have an average breakdown strength at 7.2 kV/mm. In addition, the CFO voltages of the crossarm at different lengths are presented, whereby the behavior under dry and wet conditions is comparably discussed. At the same time, the polarity effect on the CFO voltages is highlighted. The maximum E-fields at the immediate moment before breakdown are analyzed by adopting the finite element method (FEM). Non-uniform distribution of E-fields is witnessed at different parts of the crossarm structure. Simultaneously, the maximum field localized on the crossarm immediately before the breakdown is also presented.

2017 ◽  
Vol 753 ◽  
pp. 3-7
Author(s):  
Jae Ho Lee ◽  
Sun Hee Kim ◽  
Won Chang Choi ◽  
Soon Jong Yoon

Recently, glass fiber reinforced polymer plastic (GFRP) pipes are widely used in the water-supply system because of their advantages such as light-weight, corrosion resistance, etc. In previous study, we present the equation to predict stiffness factor (EI) of GFRP pipe with two tape-winding FRP layers and polymer mortar layer in between two FRP layers. As a result, it was able to predict in the range of -3% to +7%. In addition to previous study, we attempted to predict stiffness factor (EI) of GFRP pipe by the finite element method (MIDAS Civil 2016). From the study it was found that the finite element method can be used to predict the pipe stiffness of GFRP pipe.


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.


2021 ◽  
Vol 11 (8) ◽  
pp. 3429
Author(s):  
Željka Beljkaš ◽  
Nikola Baša

Deflections on continuous beams with glass fiber-reinforced polymer (GFRP) reinforcement are calculated in accordance with the appropriate standards (ACI 440.1R-15, CSA S806-12). However, experimental research provides results which differ from the values calculated pursuant to the standards, particularly when it comes to continuous beams. Machine learning methods can be applied for predicting a deflection level on continuous beams with GFRP (glass fiber-reinforced polymer) reinforcement and loaded with a concentrated load. This paper presents research on using artificial neural networks for deflection estimation and an optimal prediction model choice. It was necessary to first develop a database, in order to train the neural network. The database was formed based on the results of the experimental research on continuous beams with GFRP reinforcement. Using the best trained neural network model, high accuracy was obtained in estimating deflection, expressed over the mean absolute percentage error, 9.0%. This result indicates a high level of reliability in the prediction of deflection with the help of artificial neural networks.


Author(s):  
Priyadarsini Morampudi ◽  
Kiran Kumar Namala ◽  
Yeshwanth Kumar Gajjela ◽  
Majjiga Barath ◽  
Ganaparthy Prudhvi

Lubricants ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 22
Author(s):  
Emadelddin Hassan ◽  
Iasonas Zekos ◽  
Philip Jansson ◽  
Toa Pecur ◽  
Christophe Floreani ◽  
...  

Erosion of tidal turbine blades in the marine environment is a major material challenge due to the high thrust and torsional loading at the rotating surfaces, which limits the ability to harness energy from tidal sources. Polymer–matrix composites can exhibit leading-blade edge erosion due to marine flows containing salt and solid particles of sand. Anti-erosion coatings can be used for more ductility at the blade surface, but the discontinuity between the coating and the stiffer composite can be a site of failure. Therefore, it is desirable to have a polymer matrix with a gradient of toughness, with a tougher, more ductile polymer matrix at the blade surface, transitioning gradually to the high stiffness matrix needed to provide high composite mechanical properties. In this study, multiple powder epoxy systems were investigated, and two were selected to manufacture unidirectional glass-fiber-reinforced polymer (UD-GFRP) plates with different epoxy ratios at the surface and interior plies, leading to a toughening gradient within the plate. The gradient plates were then mechanically compared to their standard counterparts. Solid particle erosion testing was carried out at various test conditions and parameters on UD-GFRP specimens in a slurry environment. The experiments performed were based on a model of the UK marine environment for a typical tidal energy farm with respect to the concentration of saltwater and the size of solid particle erodent. The morphologies of the surfaces were examined by SEM. Erosion maps were generated based on the result showing significant differences for materials of different stiffness in such conditions.


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