Time-temperature dependence of flexural strength of unidirectional CFRP using pitch based carbon fibers.

1991 ◽  
Vol 40 (449) ◽  
pp. 192-198
Author(s):  
Yasushi MIYANO ◽  
Yukio TAKAMURA ◽  
Megumu SUZUKI ◽  
Michihiro MOHRI
Keyword(s):  
Flexural Strength ◽  
Temperature Dependence ◽  
Carbon Fibers

Study on the Composites of Phenol Formaldehyde Resin/Graphite Reinforced by Milled Carbon Fibers for Bipolar Plates

2010 ◽  
Vol 156-157 ◽  
pp. 1090-1096
Author(s):  
Wei Qiang Wang ◽  
Ai Ju Li ◽  
Ming Ming You ◽  
Bin Xia
Keyword(s):  
Electrical Conductivity ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Phenol Formaldehyde ◽  
Resin Content ◽  
Liquid Phase Oxidation ◽  
Bipolar Plates ◽  
Air Oxidation ◽  
Phase Oxidation

Composites of phenol formaldehyde (PF) resin/graphite reinforced by milled carbon fibers (MCFs) for bipolar plates are obtained by hot compression molding. The raw materials of the MCF particles, PF resin powder and graphite powder are simply dry powder ball milled and mixed. The effects of PF resin content and the content, granularity and surface treatment methods, such as air oxidation and Fenton/ultraviolet (UV) liquid-phase oxidation of MCFs on the electrical conductivity and flexural strength of the composites are measured by methods of four-point probe technique and three point flexural test, and the fracture patterns of the composites are analyzed by scanning electron microscope (SEM). The results indicate that the electrical conductivity decreases and flexural strength increases with the increase of PF resin content. Especially, the values of electrical conductivity and flexural strength can reach 165.28 S.cm-1 and 55.11MPa respectively when the PF resin content was 17% in weight. The properties of composites reinforced by air oxidation treated MCFs are better than those by liquid-phase oxidation treated one. The electrical conductivity and flexural strength of the composites are 208.12S.cm-1 and 57.44 MPa when they reinforced by 5% MCFs which treated by air oxidation at 450 . Compared with the nonreinfoced composites, the properties of reinforced composites increase 25.92% in electrical conductivity and 4.23% in flexural strength.

scholarly journals Thermo-mechanical behavior of epoxy composite reinforced by carbon and Kevlar fiber

2018 ◽  
Vol 225 ◽  
pp. 01022
Author(s):  
Falak O. Abasi ◽  
Raghad U. Aabass
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Epoxy Composites ◽  
Fiber Reinforced ◽  
Fiber Loading ◽  
Kevlar Fiber ◽  
Carbon Fiber Reinforced ◽  
Short Carbon

Newer manufacturing techniques were invented and introduced during the last few decades; some of them were increasingly popular due to their enhanced advantages and ease of manufacturing over the conventional processes. Polymer composite material such as glass, carbon and Kevlar fiber reinforced composite are popular in high performance and light weight applications such as aerospace and automobile fields. This research has been done by reinforcing the matrix (epoxy) resin with two kinds of the reinforcement fibers. One weight fractions were used (20%) wt., Epoxy reinforced with chopped carbon fiber and second reinforcement was epoxy reinforced with hybrid reinforcements Kevlar fiber and improved one was the three laminates Kevlar fiber and chopped carbon fibers reinforced epoxy resin. After preparation of composite materials some of the mechanical properties have been studied. Four different fiber loading, i.e., 0 wt. %, 20wt. % CCF, 20wt. % SKF, AND 20wt. %CCF + 20wt. % SKF were taken for evaluating the above said properties. The thermal and mechanical properties, i.e., hardness load, impact strength, flexural strength (bending load), and thermal conductivity are determined to represent the behaviour of composite structures with that of fibers loading. The results show that with the increase in fiber loading the mechanical properties of carbon fiber reinforced epoxy composites increases as compared to short carbon fiber reinforced epoxy composites except in case of hardness, short carbon fiber reinforced composites shows better results. Similarly, flexural strength test, Impact test, and Brinell hardness test the results show the flexural strength, impact strength of the hybrid composites values were increased with existence of Kevlar fibers, while the hardness was decrease. But the reinforcement with carbon fibers increases the hardness and decreases other tests.

scholarly journals CARBON FIBRE ALIGNMENT FOR REINFORCED COMPOSITES USING EMBROIDERY TECHNOLOGY

2021 ◽  
Vol 2021 ◽  
pp. 102-108
Author(s):  
J. Domenech-Pastor ◽  
P. Diaz-Garcia ◽  
D. Garcia
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Carbon Fibre ◽  
Carbon Fibers ◽  
Vertical Direction ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Reinforced Composites ◽  
Good Opportunity ◽  
Fibre Reinforced Composites

Composites are materials formed by the combination of two or more components that acquire better properties than the ones obtained by each component on its own. Composites have been widely used in the industry due to its light weight and good mechanical properties. To improve these properties several layers of reinforced material (e.g., carbon fibre) are overlapped which produce an increase in the fibre consumption. In this sense Tailored Fibre Placement (TFP) embroidery can offer good opportunity to reduce the consumption of reinforced fibre while improving the mechanical properties due to the alignment of the fibres in the effort direction. This study analyzes the performance of carbon fibre reinforced composites with Polyester resin made with TFP embroidery technology against flexural strength efforts and without using plain woven fabrics to demonstrate that the use of reinforcement fabrics in composites can be optimized by a curved alignment of the fibers. Two different structures were embroidered with TFP technology, one simulating a woven fabric with straight unidirectional alignment of fibres in horizontal and vertical direction, and a second structure made with curvilinear alignment of carbon fibers. After the study of the flexural mechanical properties an improvement of 18% was obtained in maximum flexural strength.

scholarly journals Microstructure and mechanical properties of short-carbon-fiber/Ti3SiC2 composites

2020 ◽  
Vol 9 (6) ◽  
pp. 716-725
Author(s):  
Guangqi He ◽  
Rongxiu Guo ◽  
Meishuan Li ◽  
Yang Yang ◽  
Linshan Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Vickers Hardness ◽  
Matrix Composites ◽  
Transition Layers ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Short Carbon

AbstractShort-carbon-fibers (Csf) reinforced Ti3SiC2 matrix composites (Csf/Ti3SiC2, the Csf content was 0 vol%, 2 vol%, 5 vol%, and 10 vol%) were fabricated by spark plasma sintering (SPS) using Ti3SiC2 powders and Csf as starting materials at 1300 °C. The effects of Csf addition on the phase compositions, microstructures, and mechanical properties (including hardness, flexural strength (σf), and KIC) of Csf/Ti3SiC2 composites were investigated. The Csf, with bi-layered transition layers, i.e., TiC and SiC layers, were homogeneously distributed in the as-prepared Csf/Ti3SiC2 composites. With the increase of Csf content, the KIC of Csf/Ti3SiC2 composites increased, but the σf decreased, and the Vickers hardness decreased initially and then increased steadily when the Csf content was higher than 2 vol%. These changed performances (hardness, σf, and KIC) could be attributed to the introduction of Csf and the formation of stronger interfacial phases.

scholarly journals Influence of microfillers addition on the flexural properties of carbon fiber reinforced phenolic composites

2021 ◽  
pp. 002199832110316
Author(s):  
IA Abdulganiyu ◽  
INA Oguocha ◽  
AG Odeshi
Keyword(s):  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Colloidal Silica ◽  
Flexural Modulus ◽  
Flexural Properties ◽  
Fiber Reinforced ◽  
Cfrp Composites ◽  
Sic Particles ◽  
Flexural Loading

The effects of microfiller addition on the flexural properties of carbon fiber reinforced phenolic (CFRP) matrix composites were investigated. The CFRP was produced using colloidal silica and silicon carbide (SiC) microfillers, 2 D woven carbon fibers, and two variants of phenolic resole (HRJ-15881 and SP-6877). The resins have the same phenol and solid content but differ in their viscosities and HCHO (formaldehyde) content. The weight fractions of microfillers incorporated into the phenolic matrix are 0.5 wt.%, 1 wt.%, 1.5 wt.%, and 2 wt.%. Flexural properties were determined using a three-point bending test and the damage evolution under flexural loading was investigated using optical and scanning electron microscopy. The results indicated that the reinforcement of phenolic resins with carbon fibers increased the flexural strength of the HRJ-15881 and SP-6877 by 508% and 909%, respectively. The flexural strength of the CFRP composites further increased with the addition of SiC particles up to 1 wt.% SiC but decreased with further increase in the amount of SiC particles. On the other hand, the flexural modulus of the CFRP composites generally decreased with the addition of SiC microfiller. Both the flexural strength and flexural modulus of the CFRP did not improve with the addition of colloidal silica particles. The decrease in flexural properties is caused by the agglomeration of the microfillers, with colloidal silica exhibiting more tendency for agglomeration than SiC. The fractured surfaces revealed fiber breakage, matrix cracking, and delamination under flexural loading. The tendency for failure worsened at microfiller addition of ≥1.5 wt.%.

The Temperature Dependence of Yield Stress and Fracture Toughness in Unstabilized Zirconia Crystals

1986 ◽  
Vol 78 ◽  
Author(s):  
T. W. Coyle ◽  
R. P. Ingel ◽  
P. A. Willging
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Test Temperature ◽  
Room Temperature ◽  
Single Edge ◽  
Melting Technique ◽  
Strength Tests ◽  
Edge Notch

ABSTRACTThe flexural strength and the single edge notch beam fracture toughness of undoped ZrO2 crystals, grown by the skull melting technique, were examined from room temperature to 1400°C. On heating the toughness increased with test temperature to a maximum of 4.0 MPajm at 1225°C then gradually decreased to 2.6 MPa/m. Upon cooling after a 20 minute hold at 1250°C an increase in toughness to 5 MPa/m was observed at 1200°C; upon cooling to lower temperatures Kic gradually diminished. The loaddeflection curves for the flexural strength tests showed marked nonlinearity before failure for samples tested on cooling. The temperature dependence of the apparent yield stress suggests that initial yielding occurs by slip above 1200°C but that from 1200°C to 1050°C the observed yielding is due to stress induced tetragonal to monoclinic transformation.

Influence of Fiber’s Surface State on Mechanical Properties and Fiber-Matrix Interaction of CFRP

2013 ◽  
Vol 690-693 ◽  
pp. 323-328
Author(s):  
J. J. Sha ◽  
Y.X. Zhang ◽  
J. Li ◽  
J. X. Dai ◽  
Z. Q. Wei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Functional Groups ◽  
Carbon Fibers ◽  
Surface State ◽  
Elevated Temperatures ◽  
Fiber Surface ◽  
Flexural Test ◽  
Matrix Interaction ◽  
Fiber Matrix

In order to investigate the influence of carbon fiber’s surface state on the mechanical properties and the fiber-matrix interaction of CFRP, the change of surface state was achieved by thermal treatment of carbon fibers at elevated temperatures, and the surface state was characterized by XPS. The mechanical properties were measured from the flexural test. The CFRP reinforced with 600 °C treated fabrics containing the highest reactive functional groups, showed the highest flexural strength and modulus. But in the case of CFRP reinforced with 1500 °C treated fabrics containing the lowest reactive functional groups, exhibited the lowest flexural strength and modulus. Combining the mechanical properties with the microstructure analysis, the results indicated that the fiber-matrix interaction (strong or weak) depends on the relative percentage of reactive functional groups present on the carbon fiber surface.

scholarly journals Investigation on microstructure and mechanical properties of short-carbon-fiber/Ti3SiC2 composites

2020 ◽  
Author(s):  
Guangqi He ◽  
Rongxiu Guo ◽  
Meishuan Li ◽  
Yang Yang ◽  
Linshan Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Matrix Composites ◽  
Transition Layers ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Short Carbon

Abstract In this paper, short-carbon-fibers (Csf) reinforced Ti3SiC2 matrix composites (Csf/Ti3SiC2, the Csf content was 0, 2, 5 and 10 vol.%) were fabricated by spark-plasma-sintering (SPS) using Ti3SiC2 powders and Csf as starting materials at 1300 oC. The effects of Csf addition on the phase compositions, microstructures and mechanical properties (including hardness, flexural strength and fracture toughness) of Csf/Ti3SiC2 composites were investigated. The Csf, with a bi-layered transition layers, i.e. TiC and SiC layer, were homogeneously distributed in the as-prepared Csf/Ti3SiC2 composites. With the increase of Csf content, the fracture toughness of Csf/Ti3SiC2 composites increased, but the flexural strength decreased, while the Vickers hardness decreased initially then increased steadily when the Csf content was higher than 2 vol.%. These changed performances could be attributed to the introduction of Csf and the formation of much stronger interfacial phases.

scholarly journals Mechanical Properties of SiO2-Coated Carbon Fiber-Reinforced Mortar Composites with Different Fiber Lengths and Fiber Volume Fractions

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Gwang-Hee Heo ◽  
Jong-Gun Park ◽  
Ki-Chang Song ◽  
Jong-Ho Park ◽  
Hyung-Min Jun
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Cement Matrix ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Volume Fractions ◽  
Carbon Fiber Reinforced ◽  
Coated Carbon

In the present study, SiO2 particles were coated on the surface of carbon fibers by means of chemical reaction of silane coupling agent (glycidoxypropyl trimethoxysilane, GPTMS) and colloidal SiO2 sol to improve the interfacial bonding force between fibers and matrix in cement matrix. The surface of the modified carbon fibers was confirmed through a scanning electron microscope (SEM). The mechanical properties of SiO2-coated carbon fiber mortar and uncoated carbon fiber mortar with different fiber lengths (6 mm and 12 mm) and fiber volume fractions (0.5%, 1.0%, 1.5%, and 2.0%) were compared and analyzed. The experimental results show that the flow values of the carbon fiber mortar were greatly disadvantageous in terms of fluidity due to the nonhydrophilicity of fibers and fiber balls, and the unit weight decreased significantly as the fiber volume fractions increased. However, the air content increased more or less. In addition, regardless of whether the fibers were coated, the compressive strength of carbon fiber-reinforced mortar (CFRM) composite specimens tended to gradually decrease as the fiber volume fractions increased. On the other hand, in case of the SiO2-coated CFRM composite specimens, the flexural strength was significantly increased compared to uncoated CFRM composite specimens and plain mortar specimens, and the highest flexural strength was obtained at 12 mm and 1.5%, particularly. It can be seen that the new carbon fiber surface modification method employed in this study was very effective in enhancing the flexural strength as cement-reinforcing materials.

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