Structural Behavior of Sandwich Beams with Flax Fiber–Reinforced Polymer Faces and Cardboard Cores under Monotonic and Impact Loads

2020 ◽  
Vol 26 (2) ◽  
pp. 04020013 ◽  
Author(s):  
Dillon Betts ◽  
Pedram Sadeghian ◽  
Amir Fam
Keyword(s):  
Flax Fiber ◽  
Fiber Reinforced Polymer ◽  
Structural Behavior ◽  
Impact Loads ◽  
Sandwich Beams ◽  
Fiber Reinforced ◽  
Reinforced Polymer

scholarly journals Effect of Hygrothermal Aging and Surface Treatment on the Dynamic Mechanical Behavior of Flax Fiber Reinforced Composites

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2376 ◽  
Author(s):  
Wang ◽  
Petrů
Keyword(s):  
Mechanical Behavior ◽  
Surface Treatment ◽  
Flax Fiber ◽  
Fiber Reinforced Polymer ◽  
Damping Properties ◽  
Fiber Reinforced ◽  
Hydrothermal Aging ◽  
Hygrothermal Aging ◽  
Dynamic Mechanical Behavior ◽  
Reinforced Polymer

The recent developments of FRP (fiber reinforced polymer) are towards the growth and usage of natural FRP in the field of engineering due to both environmental and economic benefits. Flax fiber is one of the most commonly used natural fibers. One of the critical factors affecting the mechanical behavior of FFRP (flax fiber reinforced polymer) is hygrothermal aging. Some experimental works have been conducted to investigate the effect of hydrothermal aging on static behavior of FFRP. However, fewer efforts have been made to study its damping properties after hydrothermal aging. In this paper, the effect of surface treatment (including alkalization, silanization, acetylation and alkali-silanization) on dynamic mechanical behavior of FFRP under hygrothermal aging is studied. The results show that water resistance and damping properties of FFRP are improved after surface treatment. The acetylation treated FFRP exhibits excellent damping performance among all treated specimens.

Experimental and analytical behaviour of sandwich composites with glass fiber-reinforced polymer facings and layered fiber mat cores

2020 ◽  
Vol 54 (30) ◽  
pp. 4875-4887
Author(s):  
Lauren MacDonnell ◽  
Pedram Sadeghian
Keyword(s):  
Glass Fiber ◽  
Analytical Model ◽  
Sandwich Beam ◽  
Fiber Reinforced Polymer ◽  
Sandwich Beams ◽  
Sandwich Composites ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced

This paper presents the results of experimental and analytical studies on the behaviour of sandwich beams fabricated with layered cores and glass fiber-reinforced polymer (GFRP) composite facings. The GFRP facings were fabricated using a unidirectional fiberglass fabric and epoxy resin, and the cores were fabricated using a thin non-woven continuous-strand polyester fiber mat with a thickness of 4.1 mm. A total of 30 sandwich beams with the width of 50 mm were prepared tested with five varying core configurations including cores made with one, two, or three layers of the fiber mat core and with or without the inclusion of intermediate GFRP layers. The specimens were tested up to failure under four-point bending at two different spans to characterize flexural and shear properties of the specimens. Two types of failure were observed, namely crushing of the compression facesheet and core shear. The load-deflection, load-strain, and moment-curvature behaviour were analyzed and using the results the flexural stiffness, shear stiffness, and core shear modulus were calculated. An analytical model was also developed to predict load-deflection behaviour and failure loading of sandwich specimens with varying core layouts. After verification, the analytical model was used for a parametric study of cases not considered in the experimental study, including additional GFRP and fiber mat core layers. It was shown that additional fiber mat core layers and the inclusion of intermediate GFRP layers can increase the strength and overall stiffness of a sandwich beam, while additional GFRP layers can only increase the overall stiffness of the system. The analytical model can be used to optimize the configuration of layered sandwich composites for cost effective rehabilitation techniques of culverts, pipelines, and other curved-shape structures where a thin, flexible core is needed to accommodate the curvature of the existing structure.

scholarly journals Behavior of fiber-reinforced polymer-strengthened reinforced concrete beams under static and impact loads

2016 ◽  
Vol 8 (1) ◽  
pp. 3-24 ◽  
Author(s):  
Thong M Pham ◽  
Hong Hao
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Impact Loads ◽  
Fiber Reinforced ◽  
Static Loads ◽  
Reinforced Polymer ◽  
Longitudinal Fiber ◽  
The Impact

This study investigates the behavior of fiber-reinforced polymer-strengthened reinforced concrete beams under static and impact loads. The experimental program includes six beams tested in static loads and seven beams tested against impact loads. Longitudinal fiber-reinforced polymer strips and fiber-reinforced polymer U-wraps were used to strengthen these beams. The section of four beams was modified to have a curved soffit in order to reduce the stress concentration of fiber-reinforced polymer U-wraps and provide confinement effect on longitudinal fiber-reinforced polymer strips. The experimental results showed that the proposed modification significantly increased the beam capacities as compared to their rectangular counterparts strengthened with the same amount of fiber-reinforced polymer material. In addition, this article also provides explanations and discussions on the phenomenon of shifting of the flexure failure mode under static loads to the shear–flexure failure mode under impact loads of all the beams tested in the study, as well as the proper interpretations of the measured impact forces in the tests. From the experimental results, it is recommended that the impact force and inertial force at the very early stage of an impact event should be used to design the impact resistance.

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