scholarly journals THE FATIGUE BEHAVIOUR OF GFRP BARS - EXPERIMENTAL STUDY

2019 ◽  
Vol 22 ◽  
pp. 38-47 ◽  
Author(s):  
Ondřej Januš ◽  
František Girgle ◽  
Iva Rozsypalová ◽  
Vojtěch Kostiha ◽  
Lenka Bodnárová ◽  
...  
Keyword(s):  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Interlaminar Shear Strength ◽  
Experimental Program ◽  
Matrix Interface ◽  
Interface Damage ◽  
Gfrp Bars ◽  
Interlaminar Shear ◽  
Fibre Matrix

The paper describes an experimental program for studying the fatigue performance of GFRP bars, which has been initiated by the authors. Two different test configurations were used to assess the fatigue behaviour. The bare specimens were tested within the first series. A modified gripping system was used to reduce eccentricity when the bar was not directly fixed. However, the boundary conditions seem to affect the results. The second series consisted of a set of specimens of bars embedded in concrete. This configuration seems appropriate for determination of fatigue life of GFRP bars. Two S-N curves for bare bars and bars embedded in concrete were created and compared. Significant reduction of interlaminar shear strength at the beginning of fatigue loading proved matrix or fibre/matrix interface damage.

Fatigue behaviour characterization of the fibre-matrix interface

1989 ◽  
Vol 24 (10) ◽  
pp. 3616-3620 ◽  
Author(s):  
R. A. Latour ◽  
J. Black ◽  
B. Miller
Keyword(s):  
Fatigue Behaviour ◽  
Matrix Interface ◽  
Fibre Matrix

scholarly journals Effects of Water and Alkaline Solution on Durability of Carbon-Glass Hybrid Fiber Reinforced Polymer Bars

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3844
Author(s):  
Yixun Yu ◽  
Yunfeng Pan ◽  
Ronggui Zhou ◽  
Xinbo Miao
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Alkaline Solution ◽  
Interlaminar Shear Strength ◽  
Diffusivity Coefficient ◽  
Hybrid Fiber ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Thin Carbon ◽  
Interlaminar Shear

The glass fiber reacts with the hydroxyl owing to the concrete pore solution. A thin coat of carbon fiber wraps around the internal GFRP bars to improve the durability of internal GFRP bars in harsh environments. This paper investigates the effect of a thin carbon fiber coat on the durability of the carbon–glass hybrid fiber reinforced polymer bars (HFRP bars) in water, and compares the performance of FRP bars in alkaline solution. To this end, the water absorption behavior, interlaminar shear strength of both the GFRP bars and the HFRP bars was characterized in water and alkaline solution. The results indicate that the diffusivity coefficient of the carbon fiber coat is higher than that of internal GFRP in water. Compared to the GFRP bars in water, the HFRP bars have a higher diffusivity coefficient and saturation water absorption. It caused that the interlaminar shear strength of the HFRP bars aged in water at a temperature of 60 °C for 140 days decreases more markedly than that of the GFRP bars aged under similar conditions. Finally, it was proved that the thin carbon fiber coat does not slow the deterioration of the GFRP bars in water, while the carbon fiber coat significantly improves the retention of the interlaminar shear strength of the HFRP bars in the alkaline solution owing to the prevention of internal glass fiber reactivated by alkali ions.

The Edge Shear Test - An Alternative Testing Method for the Determination of the Interlaminar Shear Strength in Composite Materials

2015 ◽  
Vol 825-826 ◽  
pp. 806-813 ◽  
Author(s):  
Kay André Weidenmann ◽  
Lisa Baumgärtner ◽  
Benedikt Haspel
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Shear Test ◽  
Shear Failure ◽  
Interlaminar Shear Strength ◽  
Shear Load ◽  
Testing Method ◽  
Shear Loads ◽  
Interlaminar Shear

The interlaminar shear strength is a characteristic value describing the mechanical behavior of composite materials such as laminates. Several methods for the determination of the interlaminar shear strength are described in open literature by several authors. Among these methods, the ILSS test (DIN EN ISO 14130) measuring the apparent interlaminar shear strength by using a modified bending test is the state of the art technique, as both the necessary testing equipment and the sample geometry are quite common. However, the ILSS tests implements shear loads indirectly by bending often leading to sample failure which is then not solely initiated by shear loads. Particularly for ductile matrices or those showing pronounced elastic behavior under bending, no interlaminar shear failure can be implemented and the interlaminar shear strength can not been determined or – if the user is not sensitized to the identification of non-shear failure behavior – the determined value is not correct.Up to now, alternative methods for determining the interlaminar shear strength implementing a shear load directly to the sample are quite elaborate regarding the test equipment to be used or the specimen preparation and geometry. In this contribution the authors present a novel test setup for an edge shear test which allows both a direct shear load and at the same time a reduced complexity of the specimen geometry which is comparable to those used in the ILSS test. The authors present results based on this novel testing method in comparison to conventional ILSS tests.

scholarly journals Effect of Hygrothermal Treatment on the Flexural Properties of Uhmpe Fibre/Epoxy Resin Composites

1997 ◽  
Vol 6 (4) ◽  
pp. 096369359700600 ◽  
Author(s):  
A.G. Andreopoulos ◽  
P.A. Tarantili
Keyword(s):  
Detrimental Effect ◽  
Flexural Modulus ◽  
Interlaminar Shear Strength ◽  
Flexural Properties ◽  
Resin Composites ◽  
High Modulus ◽  
Interlaminar Shear ◽  
Modulus Polyethylene ◽  
Fibre Matrix ◽  
Hygrothermal Treatment

Composite specimens with epoxy matrix containing original and treated Ultra High Modulus Polyethylene (UHMPE) fibres as reinforcement, were immersed in distilled water and kept for 10 months at temperatures ranging from 20 to 60 °C. Testing of flexural properties and interlaminar shear strength showed that in general the hygrothermal treatment had a detrimental effect on those properties, with the exception of flexural modulus which tends to increase after immersion at 20°C for specimens of poor fibre/matrix interfacial bonding.

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