scholarly journals Mechanical and Fracture Properties of Steel/GFRP Hybrid Panels for an Improved Moveable Weir after Exposure to Accelerated Natural Environmental Conditions

2019 ◽  
Vol 9 (7) ◽  
pp. 1423
Author(s):  
Seong-Yeoul Yoo ◽  
Jin-Hyung Lee ◽  
Hyung-Jin Shin ◽  
Chan-Gi Park
Keyword(s):  
Flexural Strength ◽  
Climate Conditions ◽  
Steel Panel ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
Bond Interface ◽  
Steel Panels ◽  
Flexural Tests ◽  
Panel Thickness

This study evaluated the performance of a hybrid panel in an improved moveable weir after exposure to accelerated environmental climate conditions. When exposed to a river environment, corrosion problems on improved moveable weir steel panels can occur. To address this, a hybrid panel with structure layering glass fiber-reinforced polymer (GFRP) panels on both sides of the steel panel was used. The steel was, therefore, not exposed to the outside. However, this hybrid panel is a structure that uses a mixture of two materials with different properties and there is the possibility of performance degradation when the GFRP composite material, i.e., the structure that wraps around the bond interface, and the steel panel are exposed to a river environment. Thus, we evaluated the durability of the hybrid panels by repeated exposure to long-term high temperatures, dry–wet environmental cycling, long-term freezing, and freeze–thaw cycling in an accelerated climate deterioration environment. In the flexural tests, the surface processing of the steel panel was shown to be important, with sand-blasted test specimens showing higher flexural strength. For the control specimens, the flexural strength decreased as the thickness of the GFRP panels increased. However, for the sand-blasted specimens, the flexural strength increased as the thickness of the GFRP panels increased. After exposure to accelerated climate deterioration, the flexural strength tests showed that the residual strength increased with panel thickness and that the residual strengths were greater for specimens incorporating sand-blasted steel panels. The results of our testing show that hybrid panels incorporating sand-blasted steel were adequate for use in improved moveable weirs.

EFFECT OF NANOCLAY CONTENT ON FLEXURAL PROPERTIES OF GLASS FIBER REINFORCED POLYMER (GFRP) COMPOSITES

2015 ◽  
Vol 76 (3) ◽  
Author(s):  
Widia Wahyuni Amir ◽  
Aidah Jumahat ◽  
Jamaluddin Mahmud
Keyword(s):  
Flexural Strength ◽  
Flexural Modulus ◽  
Fiber Reinforced Polymer ◽  
Flexural Test ◽  
Gfrp Composites ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
Nanoclay Content

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.

The Flexural Strength of Glass Fiber Reinforced Polyester Filled with Aluminum Tri-Hydroxide and Montmorillonite

2018 ◽  
Vol 772 ◽  
pp. 28-32 ◽  
Author(s):  
Sunarto Kaleg ◽  
Dody Ariawan ◽  
Kuncoro Diharjo
Keyword(s):  
Elastic Modulus ◽  
Flexural Strength ◽  
Glass Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
The Matrix

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.

scholarly journals Long-term Deflections of Hybrid GFRP/Steel Reinforced Concrete Beams under Sustained Loads

2020 ◽  
Vol 6 ◽  
pp. 1-11
Author(s):  
Phan Duy Nguyen ◽  
Vu Hiep Dang ◽  
Ngoc Anh Vu ◽  
Polikutin Aleksei Eduardovich
Keyword(s):  
Reinforced Concrete ◽  
Steel Reinforcement ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Rc Beams ◽  
Climate Conditions ◽  
Glass Fiber Reinforced ◽  
Sustained Loads

One of the solutions to improve the flexural behavior of Glass fiber reinforced polymer (GFRP) reinforced concrete (RC) beams is the addition of tensile longitudinal steel reinforcement. The numerous studies to date on hybrid GFRP/steel RC elements have mainly focused on the static and short-term responses, very little work has been done regarding the long-term performance. This paper presents experimental results of time-dependent deflections of cracked GFRP and hybrid GFRP/steel RC beams during a 330-day-period in natural climate conditions. Three hybrid GFRP/steel and one GFRP RC beams with dimensions 100×200×2000 mm were tested in four-point bending. Different steel reinforcement ratios were used to evaluate the effect of the steel reinforcement on the long-term behavior of the beams. Experimental results show that the immediate deflections are inversely proportional to the additional steel reinforcement. With the same initial instantaneous deflection, the total deflection increases when increasing the steel reinforcement ratio. Also, temperature (T) and relative humidity (RH) significantly affect the long-term deflection of the tested beams. The measured long-term deflections were found to be in good agreement with the theoretical values calculated from the proposed method. However, there was an overestimation when using ACI 440.1R-15 or CSA-S806-12 procedures.

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
Keyword(s):  
Flexural Strength ◽  
Composite Laminates ◽  
Impact Load ◽  
Flexural Modulus ◽  
Gfrp Composites ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
Flexural Analysis ◽  
Cyclic Impact ◽  
Point Bend

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.

scholarly journals Study on Parameter Optimization and Mechanism of Rigid-Flexible Coupling Underground Engineering Structure of Steel Panel and Polymer

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Dengping Hu ◽  
Chunyan Wang ◽  
Zhe Luo ◽  
Xuanxuan Chu
Keyword(s):  
Mechanical Properties ◽  
Polymer Structure ◽  
Rapid Expansion ◽  
Polymer Layer ◽  
Underground Engineering ◽  
Initial Attempt ◽  
Steel Panel ◽  
Superior Mechanical Properties ◽  
Steel Panels ◽  
Panel Thickness

Polymer grouting is carried out between the steel panel and surrounding soil in underground engineering, and the polymer material consists of isocyanates and polyols. The isocyanate/polyol composite slurry expands rapidly due to chemical reaction and solidifies immediately. Then, a dense impermeable polymer layer is formed after rapid expansion of isocyanate and polyol, which is widely used for ground reinforcement and foundation remediation. Thus, a steel panel-polymer composite structure is developed. Mechanical properties of the steel panel-polymer structure are studied. The results show that the steel panel-polymer structure exhibited excellent mechanical properties. The steel panel and polymer layer should be designed above 3 mm and 10 mm in thickness, respectively. The steel panel showed superior mechanical properties to those of polymer layers. Considering good rigidity of the steel panel and good flexibility of the polymer layer, the steel panel and polymer layer presented perfect interfacial contact. It is concluded that the mechanical properties of the whole structure were increasingly enhanced with the increase of the steel panel thickness and the structural flexibility increased with the thickness of the polymer layer. Besides, the combination of the steel panel and polymer layer could also improve the mechanical properties of this coupling structure. This study provided an initial attempt for investigating the feasibility of applying polyurethane foam to steel panels in underground engineering. The stress analysis along the grouting direction inside the prefabricated wall was conducted. It may lay the foundation for further application of polymer grouting in underground engineering.

scholarly journals Influence of material degradation on weld seam quality in hot gas butt welding of polyamides

2021 ◽  
Author(s):  
Max Bialaschik ◽  
Volker Schöppner ◽  
Mirko Albrecht ◽  
Michael Gehde
Keyword(s):  
Weld Seam ◽  
Experimental Investigations ◽  
Heating Process ◽  
Butt Welding ◽  
Hot Gas ◽  
Process Gas ◽  
Glass Fiber Reinforced ◽  
Extrusion Welding ◽  
Different Gases

AbstractThe joining of plastics is required because component geometries are severely restricted in conventional manufacturing processes such as injection molding or extrusion. In addition to established processes such as hot plate welding, infrared welding, or vibration welding, hot gas butt welding is becoming more and more important industrially due to its advantages. The main benefits are the contactless heating process, the suitability for glass fiber reinforced, and high-temperature plastics as well as complex component geometries. However, various degradation phenomena can occur during the heating process used for economic reasons, due to the presence of oxygen in the air and to the high gas temperatures. In addition, the current patent situation suggests that welding with an oxidizing gas is not permissible depending on the material. On the other hand, however, there is experience from extrusion welding, with which long-term resistant weld seams can be produced using air. Investigations have shown that the same weld seam properties can be achieved with polypropylene using either air or nitrogen as the process gas. Experimental investigations have now been carried out on the suitability of different gases with regard to the weld seam quality when welding polyamides, which are generally regarded as more prone to oxidation. The results show that weld strengths are higher when nitrogen is used as process gas. However, equal weld strengths can be achieved with air and nitrogen when the material contains heat stabilizers.

scholarly journals Long-term estimation of the canopy photosynthesis of a leafy vegetable based on greenhouse climate conditions and nadir photographs

2021 ◽  
Vol 289 ◽  
pp. 110433
Author(s):  
Koichi Nomura ◽  
Daisuke Yasutake ◽  
Takahiro Kaneko ◽  
Tadashige Iwao ◽  
Takashi Okayasu ◽  
...  
Keyword(s):  
Leafy Vegetable ◽  
Canopy Photosynthesis ◽  
Climate Conditions ◽  
Greenhouse Climate

Low velocity impact response and damages of GFRP composite tubes under room and cryogenic temperatures

2021 ◽  
pp. 002199832110293
Author(s):  
Memduh Kara ◽  
Mustafa Arat ◽  
Mesut Uyaner
Keyword(s):  
Room Temperature ◽  
Filament Winding ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Composite Tubes ◽  
Velocity Impact ◽  
Glass Fiber Reinforced Plastic ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
Force Time

In this paper, we have investigated the damages of glass fiber reinforced plastic (GFRP) composite tubes under the effect of low-velocity impact (LVI) at cryogenic environment conditions and room temperature. A GFRP composite tube consists of 6 layered E-glass/epoxy samples with a ± 55° winding angle, which produced by the filament winding method. Composite tubes either at room temperature or conditioned by liquid nitrogen at different temperature values (273 K, 223 K, 173 K, and 77 K) were impacted at 5, 7.5, and 10 J. Also, force-time and force-displacement graphs were plotted. The damaged regions of the samples were scrutinized. The damage areas of the GFRP composite tubes were smaller as the temperature decreased. However, the energy absorbed at low-temperature conditions was slightly higher than that absorbed in room temperature. Besides, no micro-cracks developed in the composite tubes after cryogenic conditioning.

scholarly journals Current and New Approaches to Predict the Deflections of One-Way Flexural Members with a Focus on Composite Steel Deck Slabs Voided by Circular Tubes

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 421
Author(s):  
Chang-Hwan Lee ◽  
Iman Mansouri ◽  
Jaehoon Bae ◽  
Jaeho Ryu
Keyword(s):  
Structural Function ◽  
Flexural Members ◽  
Long Span ◽  
Deck Slabs ◽  
New Type ◽  
New Perspective ◽  
Flexural Tests ◽  
Prediction Approach ◽  
Steel Deck

A new type of composite voided slab, the TUBEDECK (TD), which utilizes the structural function of profiled steel decks, has recently been proposed. Previous studies have confirmed that the flexural strength of TD slabs can be calculated based on the full composite contribution of the steel deck, but for long-span flexural members, the deflection serviceability requirement is often dominant. Herein, we derived a novel deflection prediction approach using the results of flexural tests on slab specimens, focusing on TD slabs. First, deflection prediction based on modifications of the current code was proposed. Results revealed that TD slabs exhibited smaller long-term deflections and at least 10% longer maximum span lengths than solid slabs, indicating their greater efficiency. Second, a novel rational method was derived for predicting deflections without computing the effective moment of inertia. The ultimate deflections predicted by the proposed method correlated closely with the deflection under maximum bending moments. To calculate immediate deflections, variation functions for the concrete strain at the extreme compression fiber and neutral axis depth were assumed with predictions in good agreement with experiments. The proposed procedure has important implications in highlighting a new perspective on the deflection prediction of reinforced concrete and composite flexural members.

scholarly journals Mechanical Properties of Cement-Treated Soil Mixed with Cellulose Nanofibre

2021 ◽  
Vol 11 (14) ◽  
pp. 6425
Author(s):  
Hidenori Takahashi ◽  
Shinya Omori ◽  
Hideyuki Asada ◽  
Hirofumi Fukawa ◽  
Yusuke Gotoh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Geotechnical Engineering ◽  
Strength Development ◽  
Soft Ground ◽  
Wood Cellulose ◽  
Treated Soil ◽  
Made In ◽  
Cement Treatment

Cellulose nanofibre (CNF), a material composed of ultrafine fibres of wood cellulose fibrillated to nano-order level, is expected to be widely used because of its excellent properties. However, in the field of geotechnical engineering, almost no progress has been made in the development of techniques for using CNFs. The authors have focused on the use of CNF as an additive in cement treatment for soft ground, where cement is added to solidify the ground, because CNF can reduce the problems associated with cement-treated soil. This paper presents the results of a study on the method of mixing CNF, the strength and its variation obtained by adding CNF, and the change in permeability. CNF had the effect of mixing the cement evenly and reducing the variation in the strength of the treated soil. The CNF mixture increased the strength at the initial age but reduced the strength development in the long term. The addition of CNF also increased the flexural strength, although it hardly changed the permeability.

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