An Experimental Investigation of Mechanical Strength of Knotted NiTi SMA Fiber Composite

2011 ◽  
Vol 675-677 ◽  
pp. 1147-1150
Author(s):  
Yong Li Zhao
Keyword(s):  
Mechanical Strength ◽  
Fiber Composite ◽  
Stress Transfer ◽  
Unidirectional Composite ◽  
Matrix Crack ◽  
Design Concept ◽  
Niti Sma ◽  
The Matrix ◽  
Unidirectional Composite Material ◽  
Straight Fiber

The paper presents a new design concept for evaluating the mechanical strength of unidirectional composite material with shape memory alloy (SMA) fiber in the presence of matrix crack. NiTi SMA fiber with both ends knotted is used to actively control the composite strength instead of straight fiber for purpose of better ensuring stress transfer from the matrix to the fiber. Experiment is conducted to verify the effectiveness of this new design concept.

Study on Enhancement of Mechanical Strength by Knotted Shape Memory Alloy Fiber in TiNi Fiber Composites

2008 ◽  
Vol 385-387 ◽  
pp. 421-424
Author(s):  
Yong Li Zhao ◽  
Jie Li ◽  
Ming Jin
Keyword(s):  
Shape Memory Alloy ◽  
Mechanical Strength ◽  
Shape Memory ◽  
Fiber Composite ◽  
Stress Transfer ◽  
Fiber Composites ◽  
Tension Test ◽  
Fiber Tension ◽  
The Matrix ◽  
Straight Fiber

In this paper, the experimental investigation into the enhancement of mechanical strength in shape memory alloy (SMA) fiber composites is made by using knotted fiber at the two ends instead of straight fiber. TiNi SMA fiber with both ends knotted is used for purpose of better ensuring stress transfer from the matrix to the fiber than straight fiber. Tension test is carried out above the austenitic finish temperature in air. Specimens are heated by means of electrical resistive lamplight heating. The results indicate that the mechanical strength is larger in the knotted fiber composite than in the straight fiber composite. Knotted fiber exerts the superiority of TiNi SMA fiber composite.

Nonlinear Viscoelastic Analysis of a Unidirectional Composite Material

1981 ◽  
Vol 48 (4) ◽  
pp. 859-865 ◽  
Author(s):  
B. G. Schaffer ◽  
D. F. Adams
Keyword(s):  
Composite Material ◽  
Unidirectional Composite ◽  
Time Dependent ◽  
Creep Recovery ◽  
Viscoelastic Analysis ◽  
Nonlinear Viscoelastic ◽  
The Matrix ◽  
Single Integral ◽  
Unidirectional Composite Material ◽  
Composite Response

The single-integral nonlinear viscoelastic constitutive equations developed by Schapery from thermodynamic theory have been adapted to analyze the time-dependent response of a unidirectional composite material. This viscoelastic analysis has been combined with an existing time-independent elastoplastic micromechanics analysis, to permit the study of nonlinear time-dependent response of materials loaded beyond their elastic limit. Literature values as well as a brief series of creep-recovery tests on a typical epoxy resin were used to characterize the nonlinear viscoelastic response of the matrix constituent of a composite material. Composite response under transverse loading at various stress levels was then predicted, and the results compared with actual composite creep data.

scholarly journals Fabrication and Characterization of the Modified EV31-Based Metal Matrix Nanocomposites

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Seyed Kiomars Moheimani ◽  
Mehran Dadkhah ◽  
Mohammad Hossein Mosallanejad ◽  
Abdollah Saboori
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Metal Matrix ◽  
Coefficient Of Thermal Expansion ◽  
Structural Effect ◽  
Metal Matrix Nanocomposites ◽  
Mechanical Stirring ◽  
Specific Strength ◽  
The Matrix ◽  
Matrix Nanocomposites

Metal matrix nanocomposites (MMNCs) with high specific strength have been of interest for numerous researchers. In the current study, Mg matrix nanocomposites reinforced with AlN nanoparticles were produced using the mechanical stirring-assisted casting method. Microstructure, hardness, physical, thermal and electrical properties of the produced composites were characterized in this work. According to the microstructural evaluations, the ceramic nanoparticles were uniformly dispersed within the matrix by applying a mechanical stirring. At higher AlN contents, however, some agglomerates were observed as a consequence of a particle-pushing mechanism during the solidification. Microhardness results showed a slight improvement in the mechanical strength of the nanocomposites following the addition of AlN nanoparticles. Interestingly, nanocomposite samples were featured with higher electrical and thermal conductivities, which can be attributed to the structural effect of nanoparticles within the matrix. Moreover, thermal expansion analysis of the nanocomposites indicated that the presence of nanoparticles lowered the Coefficient of Thermal Expansion (CTE) in the case of nanocomposites. All in all, this combination of properties, including high mechanical strength, thermal and electrical conductivity, together with low CTE, make these new nanocomposites very promising materials for electro packaging applications.

scholarly journals Hemp Fiber Reinforced Red Mud/Fly Ash Geopolymer Composite Materials: Effect of Fiber Content on Mechanical Strength

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 511 ◽  
Author(s):  
Eyerusalem A. Taye ◽  
Judith A. Roether ◽  
Dirk W. Schubert ◽  
Daniel T. Redda ◽  
Aldo R. Boccaccini
Keyword(s):  
Fly Ash ◽  
Mechanical Strength ◽  
Red Mud ◽  
Fiber Reinforced ◽  
Brazilian Tensile Strength ◽  
Hemp Fiber ◽  
Hemp Fibers ◽  
The Matrix ◽  
Geopolymer Composites ◽  
Scanning Electron

Novel hemp fiber reinforced geopolymer composites were fabricated. The matrix was a new geopolymer based on a mixture of red mud and fly ash. Chopped, randomly oriented hemp fibers were used as reinforcement. The mechanical properties of the geopolymer composite, such as diametral tensile (DTS) (or Brazilian tensile) strength and compressive strength (CS), were measured. The geopolymer composites reinforced with 9 vol.% and 3 vol.% hemp fiber yielded average DTS values of 5.5 MPa and average CS values of 40 MPa. Scanning electron microscopy (SEM) studies were carried out to evaluate the microstructure and fracture surfaces of the composites. The results indicated that the addition of hemp fiber is a promising approach to improve the mechanical strength as well as to modify the failure mechanism of the geopolymer, which changed from brittle to “pseudo-ductile”.

scholarly journals Stress Transfer from Axially Loaded Fiber to Matrix in a Microcomposite

1994 ◽  
Vol 365 ◽  
Author(s):  
Chun-Hway Hsueh
Keyword(s):  
Analytical Solutions ◽  
Volume Fraction ◽  
Axial Stress ◽  
Stress Transfer ◽  
Radial Dependence ◽  
Shear Lag ◽  
Shear Lag Model ◽  
The Matrix ◽  
Lag Model ◽  
Loaded Fiber

ABSTRACTThe shear lag model has been used extensively to analyze the stress transfer in a singe fiberreinforced composite (i.e., a microcomposite). To achieve analytical solutions, various simplifications have been adopted in the stress analysis. Questions regarding the adequacy of those simplifications are discussed in the present study for the following two cases: bonded interfaces and frictional interfaces. Specifically, simplifications regarding (1) Poisson's effect, and (2) the radial dependences of axial stresses in the fiber and the matrix are addressed. For bonded interfaces, the former can be ignored, and the latter can generally be ignored. However, when the volume fraction of the fiber is high, the radial dependence of the axial stress in the fiber should be considered. For frictional interfaces, the latter can be ignored, but the former should be considered; however, it can be considered in an average sense to simplify the analysis. Comparisons among results obtained from analyses with various simplifications are made.

Design and Optimization of Biopolyester Bagasse Fiber Composites

2007 ◽  
Vol 1 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Alma Hodzic ◽  
Richard Coakley ◽  
Ray Curro ◽  
Christopher C. Berndt ◽  
Robert A. Shanks
Keyword(s):  
Stress Transfer ◽  
Soxhlet Extraction ◽  
Interfacial Stress ◽  
Fiber Volume ◽  
Mechanical Reinforcement ◽  
Xylem Structure ◽  
Design And Optimization ◽  
The Matrix ◽  
Packaging Industry ◽  
Bagasse Fiber

Bagasse fiber, a by-product of the sugar making process, maintains a coherent xylem structure and can offer mechanical reinforcement to composite materials. Biopolyester bagasse composites were prepared with biodegradable matrices polyhydroxylbutyrate (PHB) and its copolymer containing polyhydroxyvalerate (PHBV). Both biopolymers were reinforced with treated and untreated bagasse fibers, as well as fiber volume fractions involving two fiber lengths. Optimized properties were achieved with PHB-bagasse composite surpassing the PHB flexural strength by 50% and achieving higher strength and modulus than the standard thermoplastics. The bagasse fibers were cleaned with boiling water and acetone soxhlet extraction to avoid using adhesive chemicals and, therefore, comply with biosafety standards in the packaging industry. A significant improvement in the interfacial stress transfer between the fiber and the matrix was achieved with the fibers subjected to both washing and acetone treatment. While the crystallization of PHBV was shown to be controllable by processing conditions, it was concluded that no transcrystalline region was formed with this particular resin in any of the composites. Bagasse was shown to be an effective filler for PHBV; although the results varied somewhat due to the surface treatment of the bagasse fibers. On average, long fiber bagasse composites displayed flexural moduli 33% higher than those of PHBV. Overall, the results demonstrated the positive potential of bagasse to reinforce both biopolyester matrices.

scholarly journals Utilization of vegetable fibers for production of reinforced cementitious materials

2018 ◽  
Vol 2 ◽  
pp. 145-154 ◽  
Author(s):  
Viviane Costa Correia ◽  
Sergio Francisco Santos ◽  
Holmer Savastano Jr ◽  
Vanderley Moacyr John
Keyword(s):  
Mechanical Performance ◽  
Stress Transfer ◽  
Cost Effective ◽  
Nanofibrillated Cellulose ◽  
Cementitious Materials ◽  
Vegetable Fibers ◽  
The Matrix ◽  
As Stress ◽  
Hybrid Reinforcement ◽  
Cellulosic Pulp

Vegetable fibers produced from agroindustrial resources in the macro, micro and nanometric scales have been used as reinforcement in cementitious materials. The cellulosic pulp, besides being used as the reinforcing element, is also the processing fiber that is responsible for the filtration system in the Hatcheck method. On the other hand, the nanofibrillated cellulose has the advantage of having good mechanical performance and high specific surface, which contributes to improve the adhesion between fiber and matrix. In the hybrid reinforcement, with micro and nanofibers, the cellulose performs bonding elements with the matrix and acts as stress transfer bridges in the micro and nano-cracking network with the corresponding strengthening and toughening of the cementitious composite. Some strategies are studied to mitigate the degradation of the vegetable fibers used in cost-effective and non-conventional fiber cement, as well as to reach a sustainable fiber cement production. As a practical example, the accelerated carbonation curing at early age is a developing technology to increase the durability of composite materials: it decreases porosity, promotes a higher density in the interface generating a good fiber–matrix adhesion and a better mechanical behavior. Thus, the vegetable fibers are potentially applicable to produce high mechanical performance and sustainable cementitious materials for use in the Civil Construction.

scholarly journals Characterization of continuous Hibiscus sabdariffa fibre reinforced epoxy composites

2022 ◽  
Vol 30 ◽  
pp. 096739112110609
Author(s):  
Atik Mubarak Kazi ◽  
Ramasastry DVA
Keyword(s):  
Fibre Orientation ◽  
Stress Transfer ◽  
Dynamic Mechanical Properties ◽  
Epoxy Composites ◽  
Neat Epoxy ◽  
Hibiscus Sabdariffa ◽  
Sem Images ◽  
Fibre Composites ◽  
The Matrix

The influence of fibre orientation on physical, mechanical and dynamic mechanical properties of Hibiscus sabdariffa fibre composites has been studied. The composites with longitudinal (0°), transverse (90°) and inclined (45°) fibre orientation were prepared using the hand layup technique. ASTM standards were used for characterization of continuous Hibiscus sabdariffa fibre composites. The composite with longitudinally placed fibres yields improved mechanical characteristics. The addition of longitudinal (0°) oriented continuous Hibiscus sabdariffa fibres to the epoxy enhances tensile strength by 460%, flexural strength by 160% and impact strength by 603% compared to neat epoxy. The longitudinal (0°) fibre oriented composite offers higher resistance to water absorption and thickness swelling compared to other types of composites. All continuous Hibiscus sabdariffa fibre epoxy composites possess an improved storage modulus than the neat epoxy resin. The glass transition temperature of continuous Hibiscus sabdariffa fibre composites is 8%–31% lower than that of neat epoxy. Scanning electron microscopy (SEM) images confirm the existence of voids in the matrix, fibre pullout and crack propagation near the fibre bundle, which indicates the stress transfer between fibre and matrix is non-uniform.

scholarly journals Method for the Microstructural Characterisation of Unidirectional Composite Tapes

2021 ◽  
Vol 5 (10) ◽  
pp. 275
Author(s):  
Nico Katuin ◽  
Daniël M. J. Peeters ◽  
Clemens A. Dransfeld
Keyword(s):  
Voronoi Tessellation ◽  
Unidirectional Composite ◽  
Fibre Volume ◽  
Cross Sectional ◽  
Reinforced Polymer ◽  
Novel Approach ◽  
The Matrix ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Microstructural Characterisation

The outstanding properties of carbon fibre-reinforced polymer composites are affected by the development of its microstructure during processing. This work presents a novel approach to identify microstructural features both along the tape thickness and through the thickness. Voronoi tessellation-based evaluation of the fibre volume content on cross-sectional micrographs, with consideration of the matrix boundary, is performed. The method is shown to be robust and is suitable to be automated. It has the potential to discriminate specific microstructural features and to relate them to processing behaviour removing the need for manufacturing trials.

scholarly journals Tensile Characterizations of Oil Palm Empty Fruit Bunch (OPEFB) Fibres Reinforced Composites in Various Epoxy/Fibre Fractions

2021 ◽  
Vol 12 (5) ◽  
pp. 6148-6163
Keyword(s):  
Sodium Hydroxide ◽  
Oil Palm ◽  
Fiber Composite ◽  
Tensile Tests ◽  
Empty Fruit Bunch ◽  
Reinforced Composites ◽  
Soaking Time ◽  
Single Fibers ◽  
The Matrix ◽  
Treated Fiber

Oil palm empty fruit bunch (OPEFB) single fibers and reinforced composites were comprehensively characterized through tensile tests to assess their performance as potential reinforcing materials in polymer composites. The performances of OPEFB single fibers and reinforced composites with untreated and treated fibers conditions were compared. The fibers were variously treated with 3% sodium hydroxide, 2% silane, 3% sodium hydroxide mixed with 2% silane, and 3% sodium hydroxide prior to 2% silane for 2 hours soaking time. The highest toughness of the single fibers test was then selected to proceed with composites fabrication. The OPEFB composites were fabricated in 90:10, 80:20, 70:30, and 60:40 epoxy-fibre fractions. The result shows that the selected treated fiber composite exhibits better performance. The selected treated fiber composite increased the highest ultimate tensile strength by 145.3% for the 90:10 fraction. The highest Young’s Modulus was increased by about 166.7% for 70:30 fraction. Next, the highest toughness was increased by 389.5% for the 30:70 fraction. The treated fibers provided a better interlocking mechanism between the matrix and fibers in reinforced composites, thus improving their interfacial bonding.

Sign in / Sign up

Export Citation Format

Share Document