Effect of Fiber Form and Volume Fraction on Fiber-Reinforced Biomimicked Composites

2012 ◽  
Author(s):  
Hussain Alghahtani ◽  
Seyed M. Allameh
Keyword(s):  
Fracture Toughness ◽  
Carbon Fibers ◽  
Volume Fraction ◽  
Structural Materials ◽  
Mechanical Tests ◽  
Fiber Reinforced ◽  
Structural Composites ◽  
Load Bearing ◽  
Short Forms ◽  
Four Point Bending

Biomimicked composites have shown to be superior to monolithic structural materials. However, they need reinforcement to replace conventional load-bearing structural composites. Carbon Fibers in long and short forms were used as reinforcement in biomimicked composites. Mechanical tests including four point bending were conducted to determine the effects of form and volume fraction of fibers on the fracture toughness of the biomimicked composites.

scholarly journals Effect of Mechanical Pretreatments on Damage Mechanisms and Fracture Toughness in CFRP/Epoxy Joints

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1512
Author(s):  
Chiara Morano ◽  
Ran Tao ◽  
Marco Alfano ◽  
Gilles Lubineau
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Polymer Matrix ◽  
Mechanical Tests ◽  
Adhesive Joints ◽  
Fiber Reinforced Polymers ◽  
Composite Joints ◽  
Damage Mechanisms ◽  
Grit Blasting

Adhesive bonding of carbon-fiber-reinforced polymers (CFRPs) is a key enabling technology for the assembly of lightweight structures. Surface pretreatment is necessary to remove contaminants related to material manufacturing and ensure bond reliability. The present experimental study focuses on the effect of mechanical abrasion on the damage mechanisms and fracture toughness of CFRP/epoxy joints. The analyzed CFRP plates were provided with a thin layer of surface epoxy matrix and featured enhanced sensitivity to surface preparation. Various degrees of morphological modification and fairly controllable carbon fiber exposure were obtained using sanding with emery paper and grit-blasting with glass particles. In the sanding process, different grit sizes of SiC paper were used, while the grit blasting treatment was carried by varying the sample-to-gun distance and the number of passes. Detailed surveys of surface topography and wettability were carried out using various methods, including scanning electron microscopy (SEM), contact profilometry, and wettability measurements. Mechanical tests were performed using double cantilever beam (DCB) adhesive joints. Two surface conditions were selected for the experiments: sanded interfaces mostly made of a polymer matrix and grit-blasted interfaces featuring a significant degree of exposed carbon fibers. Despite the different topographies, the selected surfaces displayed similar wettability. Besides, the adhesive joints with sanded interfaces had a smooth fracture response (steady-state crack growth). In contrast, the exposed fibers at grit-blasted interfaces enabled large-scale bridging and a significant R-curve behavior. While it is often predicated that quality composite joints require surfaces with a high percentage of the polymer matrix, our mechanical tests show that the exposure of carbon fibers can facilitate a remarkable toughening effect. These results open up for additional interesting prospects for future works concerning toughening of composite joints in automotive and aerospace applications.

scholarly journals Effect of Silane Coupling Treatment on the Adhesion between Polyamide and Epoxy Based Composites Reinforced with Carbon Fibers

Fibers ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 48
Author(s):  
Vincenzo Fiore ◽  
Vincenzo Orlando ◽  
Carmelo Sanfilippo ◽  
Dionisio Badagliacco ◽  
Antonino Valenza
Keyword(s):  
Carbon Fibers ◽  
Spray Deposition ◽  
Mechanical Tests ◽  
Polymer Materials ◽  
Tensile Failure ◽  
Coupling Agents ◽  
Fiber Reinforced ◽  
Silane Coupling Agents ◽  
Curing Conditions ◽  
Silane Coupling

The increasing efforts aimed to design structures with reduced weight and better mechanical performances has led in recent years to a growing use of fiber reinforced polymer materials in several fields such as marine. However, these materials can be composed of chemically very different elements and, hence, may be difficult to joint. This research aims to improve the adhesion between a thermoplastic matrix of polyamide reinforced with short carbon fibers (PA12-CR) and a carbon fiber reinforced epoxy matrix (CFRP). Two different silane coupling agents, (3-Aminopropyl)trimethoxysilane (AM) and (3-Glycidyloxypropyl)trimethoxysilane (EP), were applied, through the spray deposition method, on the PA12-CR substrate to create a reactive layer between the adherents. Different deposition methods and coupling agents curing conditions were also investigated. The wettability of the PA12-CR surface as well as the chemical modifications induced by silane treatments were investigated through contact angle and Fourier Transform Infrared spectroscopy (FTIR) analyses. Furthermore, the interfacial adhesion between PA12-CR and CFRP substrates was evaluated through Mode I delamination tests (DCB). The effectiveness of the most promising treatment was finally verified on sandwich structures, having PA12-CR printed as internal core and CFRP laminates as external skins, through quasi-static three-point bending mechanical tests. Overall, the epoxy-based silane (EP) allowed significantly better resistance to the delamination up until the tensile failure of the CFRP substrate.

scholarly journals Fiberconcrete with Non-Homogeneous Fibers Distribution

2015 ◽  
Vol 2 ◽  
pp. 67
Author(s):  
Vitalijs Lusis ◽  
Andrejs Krasnikovs
Keyword(s):  
Reinforced Concrete ◽  
Crack Opening ◽  
Fiber Reinforced Concrete ◽  
Homogeneous Distribution ◽  
Structural Elements ◽  
Fiber Reinforced ◽  
Vertical Deflection ◽  
Load Bearing ◽  
Four Point Bending ◽  
Different Types

In this research fiber reinforced concrete prisms with layers of non-homogeneous distribution of fibers inside them were elaborated. Fiber reinforced concrete is important material for load bearing structural elements. Traditionally fibers are homogeneously dispersed in a concrete. At the same time in many situations fiber reinforced concrete with homogeneously dispersed fibers is not optimal (majority of added fibers are not participating in load bearing process). It is possible to create constructions with non-homogeneous distribution of fibers in them in different ways. Present research is devoted to one of them. In the present research three different types of layered prisms with the same amount of fibers in them were experimentally produced (of this research prisms of non-homogeneous fiber reinforced concrete with dimensions 100×100×400 mm were designed. and prisms with homogeneously dispersed fibers were produced for reference as well). Prisms were tested under four point bending conditions till crack opening in each prism reached 6 mm.  During the testing vertical deflection at the center of a prism and crack opening were fixed by the linear displacements transducers in real time.

Mechanical Properties of Modified Polypropylene Coarse Fiber-Reinforced, High-Strength, Lightweight Concrete

2011 ◽  
Vol 374-377 ◽  
pp. 1499-1506
Author(s):  
Rong Hui Zhang ◽  
Jian Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
High Strength ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume

In this study, the effect of micro-expansion high strength grouting material (EGM) and Modified polypropylene coarse fiber (M-PP fiber) on the mechanical properties of lightweight concrete are investigated. The influence of EGM and M-PP fiber on compressive strength , flexural strength and drying shrinkage of concrete are researched, and flexural fracture toughness are calculated. Test results show that the effect of EGM and M-PP fiber volume fraction (Vf) on flexural strength and fracture toughness is extremely prominent, compressive strength is only slightly enhanced, and the rate of shrinkage is obviously decreased. It is observed that the shape of the descending branch of load-deflection and the ascending branch of shrinkage-age tends towards gently with the increase of Vf. And M-PP fiber reinforced lightweight aggregate concrete is more economical.

Effect of MnO on the microstructures, phase stability, and mechanical properties of ceria-partially-stabilized zirconia (Ce–TZP) and Ce–TZP–Al2O3 composites

1990 ◽  
Vol 5 (9) ◽  
pp. 1948-1957 ◽  
Author(s):  
J. S. Wang ◽  
J. F. Tsai ◽  
D. K. Shetty ◽  
A. V. Virkar
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Growth ◽  
Phase Stability ◽  
Volume Fraction ◽  
Transformation Toughening ◽  
Composite Ceramics ◽  
Four Point Bending ◽  
Crack Tips ◽  
The Stability

The effects of increasing amounts of MnO additions on the microstructures, phase stability, and mechanical properties of ZrO2–12 mol % CeO2 and ZrO2–12 mol% CeO2–10 wt.% Al2O3 were studied. MnO suppressed grain growth in ZrO2–12 mol% CeO2, while enhancing the mechanical properties significantly (strength = 557 MPa, fracture toughness = 9.3 MPa at 0.2 wt.% MnO). The enhanced mechanical properties were achieved despite an increased stability of the tetragonal phase, as evidenced by a lower burst transformation temperature (Mb) and a reduced volume fraction of the monoclinic phase on the fracture surface. In ZrO2–12 mol% CeO2–10 wt.% Al2O3, the addition of MnO suppressed the grain size of ZrO2, while promoting grain growth and changing the morphology of Al2O3. More significantly, the stability of the tetragonal ZrO2 phase decreased (high Mb temperature) with a concurrent increase in fracture toughness (13.2 MPa at 2 wt.% MnO) and transformation plasticity (1.2% in four-point bending). The widths of the transformation zones observed adjacent to the fracture surfaces showed a consistent inverse relation to the transformation yield stress, as would be expected from the mechanics of stress-induced phase transformation at crack tips. The improvements in mechanical properties obtained in the base Ce–TZP and the Ce–TZP–Al2O3 composite ceramics with the addition of MnO are critically examined in the context of transformation toughening and other possible mechanisms.

Mode I Fracture Toughness of Banana Fiber and Glass Fiber Reinforced Composites

2012 ◽  
Vol 622-623 ◽  
pp. 1320-1324
Author(s):  
V. Santhanam ◽  
M. Chandrasekaran ◽  
N. Venkateshwaran ◽  
A. Elayaperumal
Keyword(s):  
Fracture Toughness ◽  
Glass Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Polymers ◽  
Mode I ◽  
Fiber Reinforced ◽  
Banana Fiber ◽  
Mode I Fracture ◽  
Mode I Fracture Toughness ◽  
Glass Fiber Reinforced

Although fiber-reinforced polymers (FRP) have until now been largely applied to various fields of engineering, these materials have also been used in many technical applications, especially where high strength and stiffness are required, but with low component weight. Among various natural fibers, banana fiber is of particular interest in that its composites have high tensile strength, high tensile modulus, and low elongation at break beside its low cost and eases of availability. In this study, banana fiber and glass fiber reinforced polyester Resin composites were prepared using hand lay up technique . Experiments are conducted to compare and to find the effect of fiber volume fraction on mode I fracture toughness of both composites.

Experimental Study on Mechanical Properties of Steel and Polypropylene Fiber-Reinforced Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1355-1361 ◽  
Author(s):  
Liang Shan ◽  
Liang Zhang
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Mechanical Tests ◽  
Fiber Reinforced Concrete ◽  
Test Results ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Polypropylene Fiber Reinforced Concrete

The mechanical tests of normal concrete (NC) specimens, steel fiber reinforced concrete (SFRC) specimens and polypropylene fiber reinforced concrete (PPFRC) specimens have been carried out. Fiber-reinforced concretes containing different volume fraction and aspect ratio of steel and polypropylene fibers were compared in terms of compressive, splitting tensile, ultimate tensile properties. Test results indicate that the mechanical properties of NC can be improved by addition of steel fibers and can be enhanced with the increase of fiber content. However, polypropylene fiber may cause opposite effect, if volume fraction too high.

Reaction Sintering of Carbon Fiber Reinforced Silicon Carbide Composite by Gel-Casting Method with Water Soluble Epoxy Resin as Gel Former

2011 ◽  
Vol 335-336 ◽  
pp. 176-181 ◽  
Author(s):  
Jing Wei ◽  
Jing Zhong Fang ◽  
Ai Fang Zhang
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Water Soluble ◽  
Reaction Sintering ◽  
Fiber Reinforced ◽  
Casting Method ◽  
Gel Casting ◽  
Short Carbon

Reaction-bonding sintering silicon carbide (RB-SiC) toughened by 10vol% short carbon fibers were produced by Gel-casting method using water soluble epoxy as gel former and then reaction sintering at 1750°C under vacuum atmosphere for 2 h . SEM showed that short carbon fibers could disperse uniformly in the preforms and sintered carbon fiber reinforced silicon carbide composites (Cf/SiC). The mechanical test results showed that the strength decrease from 286 MPa for RB-SiC to 231 MPa for Cf/SiC, however, the fracture toughness of Cf/SiC increased from 3.65 MPa m1/2 to 5.28 MPa m1/2 compared with RB-SiC. The strength decrease of the Cf/SiC should be ascribed to the chemical reaction between the addition of short fibers and matrix, and the increase of the fracture toughness could be attributed to fiber debonding, fiber pull-out and crack deflection .

scholarly journals Flexural Characteristics of Functionally Graded Fiber-Reinforced Cementitious Composite with Polyvinyl Alcohol Fiber

2021 ◽  
Vol 5 (4) ◽  
pp. 94
Author(s):  
Toshiyuki Kanakubo ◽  
Takumi Koba ◽  
Kohei Yamada
Keyword(s):  
Polyvinyl Alcohol ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Maximum Load ◽  
Functionally Graded ◽  
Bending Test ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Four Point Bending

The objective of this study is to investigate the flexural characteristics of functionally graded fiber-reinforced cementitious composite (FG-FRCC) concerning the fiber volume fraction (Vf) varying in layers and the layered effect in bending specimens. The FG-FRCC specimens, in which Vf increases from 0% in the compression zone to 2% in the tensile zone, are three-layered specimens using polyvinyl alcohol (PVA) FRCC that are fabricated and tested by a four-point bending test. The maximum load of the FG-FRCC specimens exhibits almost twice that of homogeneous specimens, even when the average of the fiber volume fraction in the whole specimen is 1%. The result of the section analysis, in which the stress–strain models based on the bridging law (tensile stress–crack width relationship owned by the fibers) consider the fiber orientation effect, shows a good adaptability with the experiment result.

scholarly journals Impact Response of Carbon Fiber Reinforced Concrete

2020 ◽  
Vol 8 (6) ◽  
pp. 5171-5175
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Impact Loading ◽  
Modulus Of Elasticity ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Fibre Reinforced Concrete ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced

Fiber reinforced concrete is becoming increasingly more important in the construction field due to its numerous applications and advantages. Fibre reinforced concrete (FRC) is composed of fibres and matrix. Fibres constitute the reinforcements and the main source of strength while the matrix ‘glues’ all the fibres together in shape and transfers the stress between the reinforcing fibres. Different types of fibres in use are steel, glass, carbon, basalt and aramid. Fibre reinforced concrete has many advantages such as improvement in the mechanical properties like modulus of elasticity, deflection, energy absorption and crack resistance. This paper discusses the experimental investigations carried out on carbon fiber reinforced concrete under impact loading. Mix design is carried out for M25 grade of concrete reinforced with carbon fibers in proportions of 0%, 0.75%, 1.00% and 1.25% by volume fraction. The test results show that there is an increase in compressive, split tensile and flexural strengths of carbon fiber reinforced concrete (not discussed in this paper). The inclusion of 1% carbon fibers showed the maximum enhancement in strength and it can be considered as optimum dosage. When compared to conventional concrete, the crack width also reduced in carbon fiber reinforced concrete. Extensometer test was conducted to determine the modulus of elasticity of concrete. The main aim of this study is to understand the dynamic behavior of carbon fiber reinforced concrete under impact loading. For carrying out the drop-weight tests, eight slab specimens were casted. The edges of the slab were fixed on all four sides. FRC slab with 1% addition of carbon fibres gave the best results. There was a decrease in displacement and an increase in impact energy for an the aspect ratio of fiber is 45.

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