Flexural Analysis on GFRP Composites Subjected to Cyclic Gradual Load and Cyclic Impact

2013 ◽  
Vol 685 ◽  
pp. 35-39 ◽  
Author(s):  
K. Pazhanivel ◽  
N. Ramadoss ◽  
K. Poyyathappan ◽  
P. Anandan ◽  
G.B. Bhaskar

Glass fiber reinforced polymeric (GFRP) composite laminates have been prepared by hand layup method. According to ASTM standard, the test specimens have been prepared to carry out the flexural bending tests. The specimens have been subjected to both cyclic impact load and cyclic gradual load with various frequencies prior to the flexural bending analysis. Three point bend method has been adopted to find out the flexural strength and flexural modulus. Flexural strength and modulus have been calculated from the load deflection curve obtained from the tensometer for respective specimens. The flexural bending properties of GFRP composites subjected to cyclic gradual load and cyclic impact have been compared and found that the GFRP composite materials are effective for gradual cyclic load than the cyclic impact load.

2015 ◽  
Vol 76 (3) ◽  
Author(s):  
Widia Wahyuni Amir ◽  
Aidah Jumahat ◽  
Jamaluddin Mahmud

This paper presents a study on the flexural properties of glass fiber reinforced polymer composites. The epoxy-nanoclay resin was milled using a three roll mill machine to produce exfoliated structure nanocomposites. The fiber laminates specimens were manufactured by vacuum bagging system. These specimens were tested in the three point bend configuration following the ASTM D7264. The flexural modulus, flexural strength and strain to failure were then determined based on the flexural test results. The results showed that flexural modulus and flexural strength increases when a certain amount of nanoclay was included in the resin system. A maximum of 80% and 37% improvement of flexural strength and flexural modulus, respectively, were found at 5 wt% nanoclay content when compared to the neat GFRP composite. The improved properties of GFRP composites were achieved mostly due to an increase on the interfacial surface areas as well as a well-dispersion of nanoclay in the GFRP composite system. The fracture surfaces of specimens after flexural test were observed under FESEM. The results showed that the compressive failure region in the fiber was a dominant failure mechanism of the specimens due to a large compressive area on the fracture surface.


2021 ◽  
Vol 9 (4) ◽  
pp. 379
Author(s):  
Sang-Gyu Lee ◽  
Daekyun Oh ◽  
Jong Hun Woo

Ship structures made of glass fiber-reinforced polymer (GFRP) composite laminates are considerably thicker than aircraft and automobile structures and more likely to contain voids. The production characteristics of such composite laminates were investigated in this study by ultrasonic nondestructive evaluation (NDE). The laminate samples were produced from E-glass chopped strand mat (CSM) and woven roving (WR) fabrics with different glass fiber contents of 30–70%. Approximately 300 pulse-echo ultrasonic A-scans were performed on each sample. The laminate samples produced from only CSM tended to contain more voids compared with those produced from a combination of CSM and WR, resulting in the relative density of the former being lower than the design value, particularly for high glass fiber contents of ≥50%. The velocity of the ultrasonic waves through the CSM-only laminates was also lower for higher glass fiber contents, whereas it steadily increased for combined CSM–WR laminates. Burn-off tests of the laminates further revealed that the fabric configuration of the combined CSM–WR laminates was of higher quality, prevented the formation of voids, and improved inter-layer bonding. These findings indicate that combined CSM–WR laminates should be used to achieve more accurate ultrasonic NDE of GFRP composite structures.


2018 ◽  
Vol 25 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Jinshui Yang ◽  
Chunqi Wang ◽  
Jingcheng Zeng ◽  
Dazhi Jiang

AbstractThe unmodified and nano-SiO2modified glass fiber reinforced polymer (GFRP) composites were prepared by the hot-compression molding process to investigate the effects of nano-SiO2on the mechanical and hygric properties of the GFRP composites. The results indicate that the nano-SiO2modification results in an increase of 9.7% and 7.9% in the tensile and flexural strength of the GFRP composites, and a decrease of 10.6% in the interlaminar shear strength (ILSS). The maximum swelling of the unmodified GFRP is 2.6 times as that of the nano-SiO2modified GFRP. The normalized-ILSS decrease of the nano-SiO2modified GFRP is only 12% after 138 days aging, while that of the GFRP reaches 31%. After 95-days hygric-aging, the decrease of the normalized flexural strength is 15.3% for the GFRP, while the normalized flexural strength of the nano-SiO2modified GFRP still maintains an increase of 5.0%. It is concluded that the nano-SiO2particle could improve the mechanical and hygric properties of the GFRP composites.


Author(s):  
GangaRao V. S. Hota ◽  
P. V. Vijay ◽  
Reza S. Abhari

The use of glass fiber reinforced polymer (GFRP) composite materials to rehabilitate timber Railroad Bridge is investigated in this research. Two different rehabilitation methods were developed and implemented to strengthen timber stringers using GFRP. These methods are referred to as GFRP spray lay-up and vacuum bagging of GFRP wraps around timber members. Tests were conducted on four full scale (8″×16″×12″) timber stringers in the WVU-CFC laboratory under four point bending loads. These creosote treated timber stringers were loaded up to 20% of their ultimate loads to verify their properties. The stringers were then repaired using the above two rehabilitation methods and retested to failure. Strengthening the stringers with GFRP composites increased the shear moduli of the two stringers by 41% and 267%. Rehabilitation and load testing were carried out on an open-deck-timber railroad bridge built during early 1900’s on the South Branch Valley Railroad (SBVR) owned by the WVDOT in Moorefield, WV. Specifically, field rehabilitation involved repairing piles using GFRP composite wraps and phenolic formaldehyde adhesives. Using a 80-ton locomotive, static and dynamic tests were performed to determine the dynamic response of the substructure. Rehabilitated SBVR Bridge showed a 43% and 46% strain reduction in the piles and pile cap, respectively.


2018 ◽  
Vol 772 ◽  
pp. 28-32 ◽  
Author(s):  
Sunarto Kaleg ◽  
Dody Ariawan ◽  
Kuncoro Diharjo

Aluminum tri-hydroxide (ATH) and montmorillonite (MMT) are capable to enhance flame retardancy of glass fiber reinforced polymer (GFRP). Nevertheless, the combination of both flame retardant fillers on changes in the mechanical properties of GFRP is not yet known. The characterization of flexural strength and scanning electron microscope (SEM) observation on GFRP composite has been done. The result of flexural properties testing shows that the addition of ATH or MMT or a combination of both on the GFRP causes a decrease in flexural strength. GFRP with increased ATH loading causes an increase in elastic modulus. Contrarily, the MMT addition causes a decrease in the elastic modulus of the GFRP composite. SEM results on the fractured samples show that the high content of ATH or MMT in the UP tends to agglomerate thus showing visible holes that were formed from the filler particles pulled out from the matrix.


2021 ◽  
Vol 4 (4) ◽  
pp. 227-238
Author(s):  
Alper Karadis ◽  
Kabil Cetin ◽  
Taha Yasin Altıok ◽  
Ali Demir

Glass fiber reinforced polymer (GFRP) composites have been frequently used in engineering applications in recent years. GFRP composites produced by using glass fiber and epoxy resin have significant advantages such as high strength, lightness, and resistance against corrosion. However, GFRP composites exhibit a more brittle behavior than steel bars. This study aims to investigate both the experimental and numerical bending behavior of slabs with GFRP bars, steel bars, and polypropylene fiber. Within the scope of experimental studies, 5 slabs were built. Two slabs called SS-1 and SS-2 have only steel bars. Two slabs called GFRPS-1 and GFRPS-2 have only GFRP composite bars. A slab called GFRPS-F has both GFRP composite bars and polypropylene fibers. Polypropylene fibers are added to fresh concrete to improve the slab’s ductility. Three-point bending tests have been carried out on the slabs. All slabs are subjected to monotonic increasing distributed loading until collapse. As a result of tests, GFRPS slabs have carried %53 higher load than SS slabs. However, the SS slabs have exhibited a more ductile behavior compared to the GFRPS slabs. GFRPS slabs have more and larger crack width than other slabs. The addition of 5% polypropylene fiber by volume to concrete has a significant contributed to ductility and tensile behavior of slab. The average displacement value of GFRPS-F slab is 22.3% larger than GFRPS slab. GFRPS-F slab has better energy consumption capacity than other slabs. The energy consumption capacity of GFRPS-F slab is 1.34 and 1.38 times that of SS and GFRPS slabs, respectively. The number of cracks in GFRPS-F slab is fewer than GFRPS slabs. The fibers have contributed to the serviceability of the GFRPS slabs by limiting the displacement and the crack width. GFRPS-F exhibits elastoplastic behavior and almost returns to its first position when the loading is stopped. In addition, experimental results are verified with numerical results obtained by using Abaqus software. Finally, it is concluded that GFRP composite bars can be safely used in field concretes, concrete roads, prefabricated panel walls, and slabs.


2022 ◽  
Vol 58 (4) ◽  
pp. 28-36
Author(s):  
Velmurugan Natarajan ◽  
Ravi Samraj ◽  
Jayabalakrishnan Duraivelu ◽  
Prabhu Paulraj

This study aims to reveal the consequence of thickness reinforcement on Fiber Laminates (Polyester Resin, Glass Fiber, Aluminum, and Bentonite) and to see if it can enhance the mechanical properties and resistance of laminates. Glass fiber reinforced polymer composites have recently been used in automotive, aerospace, and structural applications where they will be safe for the application s unique shape. Hand layup was used to fabricate three different combinations, including Aluminium /Glass fiber reinforced polyester composites (A/GFRP), Bentonite/Glass fiber reinforced polyester composites (B/GFRP), and Aluminium&Bentonie/Glass fiber reinforced polyester composites (AB/GFRP). Results revealed that AB/GFRP had better tensile strength, flexural strength, and hardness than GFRP and A/GFRP. Under normal atmospheric conditions and after exposure to boiling water, hybrid Aluminium&Bentonite and glass fiber-reinforced nanocomposites have improved mechanical properties than other hybrid composites. After exposure to temperature, the flexural strength, tensile strength and stiffness of AB/GFRP Composites are 40 % higher than A/GFRP and 17.44% higher than B/GFRP Composites.


Author(s):  
Getahun Aklilu ◽  
Sarp Adali ◽  
Glen Bright

Abstract. Fibre Reinforced Plastic (FRP) materials are widely used in several key engineering applications such as ships, aircraft, wind turbine blades, helicopter blade, automobiles, and other transportation vehicles because of their mechanical properties and tailoring capabilities.Carbon and glass fibres are the most popular fibre reinforcements used for composite components. In the present study, two different stacking sequences, (0 degrees) and (0/90 degrees), are selected to study effect of fibre hybridization on flexural performance using three-point bending tests. Materials used are E-glass and T-300 carbon fibres in an epoxy matrix and the laminates were produced by resin transfer moulding methods. Fracture surfaces of composite laminates were examined using a scanning electron microscope. The results showed that the flexural strength, modulus and strain at failure of unidirectional and bidirectional composite laminates were strongly influenced by stacking sequences, fibre orientation and the hybrid ratio of the fibres. A higher flexural modulus was achieved when carbon fibres were placed on the compressive side. Hybrid specimens showed higher flexural strength and modulus by 21.08% and 145.39%, respectively, compared to the pure glass fibre reinforced laminates. On the other hand, flexural strength and modulus of hybrid specimen were less by 6.50% and 8.20%, respectively, as compared to carbon fibre reinforced specimens. Stacking sequences and hybrid ratio of glass/carbon fibre reinforced specimens were investigated with a view towards improving the mechanical properties of hybrid composites.


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