Modeling Strength and Stress Diffusion in Hip Prostheses with Nano-Reinforced Composites

2017 ◽  
Vol 749 ◽  
pp. 234-240
Author(s):  
Chen Yuan Chung
Keyword(s):  
Carbon Fibers ◽  
Glass Fibers ◽  
Elastic Solid ◽  
Reinforced Composites ◽  
End Effects ◽  
Hip Prostheses ◽  
Rigid Particles ◽  
Stress Diffusion ◽  
Binding Phase ◽  
Rigid Fibers

nanoscale rigid particles or plates are investigated for their reinforcing properties used as a binding material for holding together many long fiber composites. Very strong and light laminates can be made by layering thin sheets of rigid fibers (e.g. carbon fibers, glass fibers) with epoxy resin, for example, as a filler for spaces between fibers. Saint-Venant’s principle is concerned with assessing the effect of anisotropy on the decay of stresses with distance from the boundary of an elastic solid subjected to self-equilibrated end loads. The distance required for this transition is longer for rigid composites than for isotropic materials. The extra distance will allow bio-stress to be diffused to the boundary where end effects occur. This study is based on a biomimetic idea come from the mechanical behavior of biological materials as governed by underlying nanostructure, with the potential for synthesis into engineered materials. Mixing extremely small, rigid, randomly oriented nanoplates or nanotubes into the binding phase between the fibers is found to make the composite more isotropic near the ends and therefore mitigate damage.

Hemp Fiber Reinforced Composites: Morphological and Mechanical Properties

2011 ◽  
Vol 332-334 ◽  
pp. 121-125
Author(s):  
Xing Mei Guo ◽  
Yi Ping Qiu
Keyword(s):  
Polymer Composites ◽  
Unsaturated Polyester ◽  
Glass Fibers ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Hemp Fiber ◽  
Plant Fibers ◽  
Natural Plant ◽  
Reinforcing Fillers

The use of natural plant fibers as reinforcing fillers in fiber-polymer composites has drawn much interest in recent years. Natural plant fibers as reinforcing fillers have several advantages over inorganic fillers such as glass fibers; they are abundant, readily available, renewable, inexpensive, biodegradable, of low density, and of high specific strength. Hemp fibers are one of the most attractive natural plant fibers for fiber-reinforced composites because of their exceptional specific stiffness. In this review, we summarize recent progress in developments of the hemp fiber reinforced composites such as hemp fiber reinforced unsaturated polyester (UPE), hemp fiber reinforced polypropylene (PP), hemp fiber reinforced epoxy composites, and so on, illustrate with examples how they work, and discuss their intrinsic fundamentals and optimization designs. We are expecting the review to pave the way for developing fiber-polymer composites with higher strength.

scholarly journals Modified rule of mixtures and Halpin–Tsai model for prediction of tensile strength of micron-sized reinforced composites and Young’s modulus of multiscale reinforced composites for direct extrusion fabrication

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878528 ◽  
Author(s):  
Zirong Luo ◽  
Xin Li ◽  
Jianzhong Shang ◽  
Hong Zhu ◽  
Delei Fang
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Carbon Fibers ◽  
Epoxy Resins ◽  
Young's Modulus ◽  
Resin Matrix ◽  
Reinforced Composites ◽  
Rule Of Mixtures ◽  
Combined Use

A modified rule of mixtures is required to account for the experimentally observed nonlinear variation of tensile strength. A modified Halpin–Tsai model was presented to predict the Young’s modulus of multiscale reinforced composites with both micron-sized and nano-sized reinforcements. In the composites, both micron-sized fillers—carbon fibers—and nano-sized fillers—rubber nanoparticles and carbon nanotubes—are added into the epoxy resin matrix. Carbon fibers can help epoxy resins increase both the tensile strength and Young’s modulus, while rubber nanoparticles and carbon nanotubes can improve the toughness without sacrificing other properties. Mechanical experiments and scanning electron microscopy observations were used to study the effects of the micron-sized and nano-sized reinforcements and their combination on tensile and toughness properties of the composites. The results showed that the combined use of multiscale reinforcements had synergetic effects on both the strength and the toughness of the composites.

Thermomechanical Stability of Interphases in Glass Reinforced Composites

1989 ◽  
Vol 170 ◽  
Author(s):  
A. T. Dibenedetto ◽  
Jaime A. Gomez ◽  
C. Schilling ◽  
F. Osterholtz ◽  
G. Haddad
Keyword(s):  
Thermal Stability ◽  
Shear Strength ◽  
Glass Fibers ◽  
Boiling Water ◽  
Reinforced Composites ◽  
Matrix Interface ◽  
Force Transmission ◽  
Silane Coating ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

AbstractThe thermomechanical stability of organosilane surface treatments for E-glass fibers used in fiber reinforced composites was evaluated. The effect of molecular structure of 40 to 80 namometer coatings on the force transmission across the fiber/matrix interface was measured as a function of temperature and exposure to water using a fiber fragmentation test. It was found that phenyl-substituted amino silanes exhibited better thermal stability, but were less resistant to boiling water, than the commierically available γ-amino propyl silanes. A bis-trimethoxy γ-amino propyl silane showed an increase in both the hydrolytic and thermal stability when compared to the commiercial product. A good balance of thermal and hydrolytic stability was also obtained with a methylaminopropyltrimethoxy silane coating.The strain energy released from the glass fibers upon decoupling from the poxy matrix or silane coating was found to be in the range of 145 to 186 g/m2 and varied no more than 20 percent over a temperature range of 25 to 75°C or when exposed to boiling water and then redried. It also varied very little with the silane coating used. In addition, the average shear stress attained at the fiber-matrix interface in an imbedded single fiber test at 25°C was as much as two times higher than the shear strength of the epoxy matrix and as much as five times higher at elevated temperature. These data lead one to the conclusion that the interphase failure in these composites is controlled by a plane strain fracture in the constrained region of the organic phase, near the fiber surface, rather than by the maximum shear strength in the interphase.

Flexural Response of Inorganic Hybrid Composites With E-Glass and Carbon Fibers

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
James W. Giancaspro ◽  
Christos G. Papakonstantinou ◽  
P. N. Balaguru
Keyword(s):  
Carbon Fibers ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Hybrid Composites ◽  
Glass Fibers ◽  
Composite Plates ◽  
Carbon Composite ◽  
Primary Objective ◽  
Flexural Capacity ◽  
Compression Failure

By far, carbon and glass fibers are the most popular fiber reinforcements for composites. Traditional carbon composites are relatively expensive since the manufacturing process requires significant heat and pressure, while the carbon fibers themselves are inherently expensive to produce. In addition, they are often flammable and their use is restricted when fire is a critical design parameter. Glass fabrics are approximately one order of magnitude less expensive than similar carbon fabrics. However, they lack the stiffness and the durability needed for many high performance applications. By combining these two types of fibers, hybrid composites can be fabricated that are strong, yet relatively inexpensive to produce. The primary objective of this study was to experimentally investigate the effects of bonding high strength carbon fibers to E-glass composite cores using a high temperature, inorganic matrix known as geopolymer. Carbon fibers were bonded to E-glass cores (i) on only the tension face, (ii) on both the tension and compression faces, or (iii) dispersed throughout the core in alternating layers to obtain a strong, yet economical, hybrid composite laminate. For each response measured (flexural capacity, stiffness, and ductility), at least one hybrid configuration displayed mechanical properties comparable to all carbon composite laminates. The results indicate that hybrid composite plates manufactured using 3k unidirectional carbon tape exhibit increases in flexural capacity of approximately 700% over those manufactured using E-glass fibers alone. In general, as the relative amount of carbon fibers increased, the likelihood of precipitating a compression failure also increased. For 92% of the specimens tested, the threshold for obtaining a compression failure was utilizing 30% carbon fibers. The results presented herein can dictate future studies to optimize hybrid performance and to achieve economical configurations for a given set of design requirements.

scholarly journals Testing the Force Absorption of Composite Materials to Select the Best for Making a Helmet

2021 ◽  
Vol 15 (4) ◽  
pp. 581-584
Author(s):  
Božo Bujanić ◽  
Matija Košak
Keyword(s):  
Carbon Fibers ◽  
Material Selection ◽  
Glass Fibers ◽  
Test Procedure ◽  
Test Results ◽  
Aramid Fibers ◽  
Absorption Properties ◽  
Eu Project ◽  
Impact Absorption ◽  
The Eu

The paper presents and describes the procedure of testing the materials that were available for the production of a multifunctional protective helmet. The procedure was carried out at the company Šestan-Busch d.o.o. as part of the EU project for the development and production of a multifunctional protective helmet. The test results showed that carbon fibers polymers as a composite material have the best impact absorption properties which was a key criterion for material selection. Other materials; glass fibers polymers, aramid fibers polymers and combinations in the test procedure showed worse results compared to the selected criterion.

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.

Rheological and mechanical properties of polyphenylene sulfide reinforced with round and rectangle cross-section glass fibers

2016 ◽  
Vol 29 (7) ◽  
pp. 849-856
Author(s):  
Tao Jiang ◽  
Chengzhen Geng ◽  
Hanmei Zhou ◽  
Ai Lu
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Glass Fibers ◽  
Polyphenylene Sulfide ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Reinforcing Effect ◽  
Fiber Cross Section ◽  
Cross Section Shape ◽  
Section Shape

Two kinds of glass fibers with round (RdGF) and rectangle cross-sections (RcGF) were used to reinforce polyphenylene sulfide (PPS), respectively. In this way, the effect of fiber cross-section shape on rheological and mechanical properties of the composites was studied for the first time. Results showed that the viscosity of the composites reinforced with RcGF was much lower than that of RdGF composites, owing to their higher sensitivity to flow. As a result, PPS/RcGF composites could be injection-molded at high fiber contents. Moreover, RcGF showed a better reinforcing effect on mechanical properties of PPS. So the use of RcGF could better balance the contradiction between processability and reinforcing effect for glass fiber-reinforced composites. Various characterizations were carried out to reveal the reinforcing mechanism. This work demonstrated the importance of fiber cross-section shape on design and production of fiber-reinforced composites.

Feasibility and Characterization of Large-Scale Additive Manufacturing With Long Fiber Reinforced Composites

2020 ◽  
Author(s):  
Aditya R. Thakur ◽  
Ming C. Leu ◽  
Xiangyang Dong
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Large Scale ◽  
Flexural Modulus ◽  
High Deposition Rate ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
Long Carbon Fibers

Abstract A new additive manufacturing (AM) approach to fabricate long fiber reinforced composites (LFRC) was proposed in this study. A high deposition rate was achieved by the implementation of a single-screw extruder, which directly used thermoplastic pellets and continuous fiber tows as feedstock materials. Thus, the proposed method was also used as a large-scale additive manufacturing (LSAM) method for printing large-volume components. Using polylactic acid (PLA) pellets and continuous carbon fiber tows, the feasibility of the proposed AM method was investigated through printing LFRC samples and further demonstrated by fabricating large-volume components with complex geometries. The printed LFRC samples were compared with pure thermoplastic and continuous fiber reinforced composite (CFRC) counterparts via mechanical tests and microstructural analyses. With comparable flexural modulus, the flexural strength of the LFRC samples was slightly lower than that of the CFRC samples. An average improvement of 28% in flexural strength and 50% in flexural modulus were achieved compared to those of pure PLA parts, respectively. Discontinuous long carbon fibers, with an average fiber length of 20.1 mm, were successfully incorporated into the printed LFRC samples. The carbon fiber orientation, distribution of carbon fiber length, and dispersion of carbon fiber as well as porosity were further studied. The carbon fibers were highly oriented along the printing direction with a relatively uniformly distributed fiber reinforcement across the LFRC cross section. With high deposition rate (up to 0.8 kg/hr) and low material costs (< $10/kg), this study demonstrated the potentials of the proposed printing method in LSAM of high strength polymer composites reinforced with long carbon fibers.

SUB-MICROSCALE SPECKLE PATTERN CREATION ON SINGLE CARBON FIBERS FOR IN-SITU DIC EXPERIMENTS

2021 ◽  
Author(s):  
KARAN SHAH ◽  
GENE YANG ◽  
MOHAMMAD EL LOUBANI ◽  
SUBRAMANI SOCKALINGAM ◽  
DONGKYU LEE
Keyword(s):  
Carbon Fibers ◽  
Fiber Strength ◽  
Glass Fibers ◽  
Speckle Pattern ◽  
Fiber Surface ◽  
Average Diameter ◽  
Sputter Deposition ◽  
Image Correlation ◽  
Longitudinal Tensile Strength ◽  
Fiber Breaks

High performance carbon and glass fibers are widely used as reinforcements in composite material systems for aerospace, automotive, and defense applications. Modifications to fiber surface treatment (sizing) is one of the ways to improve the strength of fibers and hence the overall longitudinal tensile strength of the composite. Single fiber tensile tests at the millimeter scale are typically used to characterize the effect of sizing on fiber strength. However, the characteristic length-scale governing the composite failure due to a cluster of fiber breaks is in the micro-scales. To access such micro-scale gage-lengths, we aim to employ indenters of varying radii to transversely load fibers and use scanning electron microscope (SEM) with digital image correlation (DIC) to measure strains at these lengthscales. The use of DIC technique requires creation of a uniform, random, and high contrast speckle pattern on the fiber surface such as that shown in Figure 1. In this work, we investigate the formation of sub-microscale speckle pattern on carbon fiber surface via sputter deposition and pulsed laser deposition techniques (PLD) using Gold-Palladium (Au-Pd) and Niobium-doped SrTiO3 (Nb:STO) targets respectively. Different processing conditions are investigated for both sputter deposition: sputtering current and coating duration, and PLD: number of pulses respectively to create sub-micron scale patterns viable for micro-DIC on both sized and unsized carbon fibers. By varying the deposition conditions and SEM-imaging the deposited patterns on fibers, successful pattern formation at sub-micron scale is demonstrated for both as-received sized and unsized IM7 carbon fibers of average diameter 5.2 μm via sputter deposition and PLD respectively.

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