Effect Of Fiber Fraction Research Articles

Effect of Fiber Fraction on Ballistic Impact Behavior of 3D Woven Composites

This paper studies the ballistic impact performance of 3D woven composites (3DWCs) with hexagonal binding patterns. Para-aramid/polyurethane (PU) 3DWCs with three kinds of fiber volume fraction (Vf) were prepared by compression resin transfer molding (CRTM). The effect of Vf on the ballistic impact behavior of the 3DWCs was analyzed by characterizing the ballistic limit velocity (V50), the specific energy absorption (SEA), the energy absorption per thickness (Eh), the damage morphology and the damage area. 1.1 g fragment-simulating projectiles (FSPs) were used in the V50 tests. Based on the results, when the Vf increases from 63.4% to 76.2%, the V50, the SEA and the Eh increase by 3.5%, 18.5% and 28.8%, respectively. There are significant differences in damage morphology and damage area between partial penetration (PP) cases and complete penetration (CP) cases. In the PP cases, the back-face resin damage areas of the sample III composites were significantly increased to 213.4% of the sample I counterparts. The findings provide valuable information for the design of ballistic protection 3DWCs.

Effect of fiber fraction on the physical and mechanical properties of short areca sheath fiber reinforced polymer composite

The fiber fraction in a composite will have a significant influence on its behavioural aspects and is reported in the current study. With different fiber fractions (0, 12, 24, 36 and 48 wt%) of the areca sheath fiber reinforcing agent, composite specimens were prepared and its physical and mechanical properties were examined. The measured density of the neat epoxy to the higher fiber fraction composite specimen (48 wt%) varies from 1.147 to 0.9524 g/cm 3 , from which it is evident that the density decreases with increase in the fiber concentration. On the other hand, void fraction for a neat epoxy is 0.26% which increases with the increase in the fiber concentration and is 6.14% for the 48 wt% fiber loaded specimen. An optimum values of investigated mechanical properties such as the hardness (72.56 HRB), Young’s modulus (1.98 GPa), and the Impact strength (4.724 J) have been observed with the increase in fibre fraction. The flexural strength for the neat epoxy is 46.28 MPa starts decreasing with the inclusion of fibers and reaches 12.05 MPa at a higher fraction of 48 wt%. The similar declining behaviour may be observed for the flexural modulus of 0.26 GPa and tensile strength of 14.02 MPa at high fiber fraction.

Hygroscopic multi-scale behavior of polypropylene matrix reinforced with flax fibers

Due to the hydrophilic behavior of natural fibers, bio-based composites made of vegetal fibers are still facing some obstacles that impair their large-scale development in the modern and promising industrial applications. Therefore, the aim of this study is to evaluate the multi-scale moisture absorption phenomena within a unidirectional bio-based composite material reinforced with flax fibers. The effect of fiber fraction, coupling agent and relative humidity on diffusion kinetics have been studied. In this work, composites are made of polypropylene matrix with various flax fiber contents, with the addition of maleic anhydride as a coupling agent. Samples were submitted to wet aging at 75% and 95% relative humidities (RH) under room temperature of 23 °C. Results have shown significant increase of moisture absorption with the increase of fiber content and relative humidity. In fact, the samples reinforced with 40% flax fiber content absorb as much as 9.15% moisture at saturation at 95% RH, whereas the samples reinforced with 20% flax fiber content only absorb 4.91% moisture at the same RH condition. However, with the addition of a coupling agent, composites undergo a decrease in moisture absorption due to an improved adhesion at the fiber/matrix interface. The moisture content of the samples reinforced with 40% flax fiber has indeed been reduced to 7.52% at 95% RH owing to the addition of the coupling agent. In this work, for the first time, the prediction of the maximum moisture absorption capacity of a bio-based composite has been studied, using a multiscale homogenization method. The obtained results highlight that once the fibers are incorporated within the matrix, the overall macroscopic property of the composite does not always satisfy the classical law of mixture, even for the maximum moisture absorption capacity. In fact, it has been concluded that the difference between the experimental results and those of the homogenization method is primarily due to a hygro-mechanical coupling, induced by the containment effect the matrix exerts on the fibers. This prediction strongly depends on the fiber content, the environmental relative humidity and the flax fiber sorption behavior which can vary from a fiber to another.

GLASS FIBER POLYMER ON THE FRESH AND HARDENED PROPERTIES OF CONCRETE

The study describes an experimental study into the relationship among incorporation of Glass Fiber on the fresh and hardened properties of concrete. The effect of fiber fractions on the slump, compressive strength, splitting tensile strength and flexural strength of Glass Fiber Reinforced Concrete (GFRC) were investigated for volume fraction (VF) of 0%, 1%, 2% and 4%. In order to serve the purpose, concrete cylindrical and prism specimens were made with various rates of fiber-glass polymer. The cylinder specimens were tested at 7 and 28 days for compressive strength and at 28 days for splitting tensile strength, whereas the prism specimens were tested at 28 days for flexural strength. The experimental test results show that the additions of glass fiber polymer to concrete decrease slump, but increase compressive strength, splitting tensile strength and flexural strength. In addition, an analytical model has been proposed to predict slump of fresh concrete.

Effects of Fiber Fraction on the Mechanical and Abrasion Properties of Treated Cow Hair Fiber Reinforced Polyester Composites

Effects of Fiber Fraction on the Mechanical and Abrasion Properties of Treated Cow Hair Fiber Reinforced Polyester Composites

Random chopped fibers in reaction bonded SiC composite: Morphology, etching and reinforcing properties

Random chopped fibers were introduced into SiC/C slurry to improve the mechanical behaviors of reaction bonded SiC ceramics. The distribution, morphology and chemical properties of the siliconized carbon fiber were investigated. The effect of fiber fraction on mechanical behaviors of the reaction bonded silicon carbide composite was studied. The siliconization reaction led to a dense layer of nano and micron SiC particles on the fiber surface. Based on the morphology changes in the acid etching test, a structural model of the siliconized fiber was proposed. The fracture toughness and the flexural strength of the composite were improved by the random chopped fiber, reaching the peak values of 5.1MPam0.5 and 416MPa, respectively, at the fiber fraction of 30vol.%.

Effects of random chopped fiber on the flexural strength and toughness of reaction bonded silicon carbide composite

Chopped carbon fibers were introduced into the SiC/C suspensions to enhance the mechanical behaviors of reaction bonded silicon carbide ceramics. The effects of fiber fraction on the flexural strength and fracture toughness were investigated. No preferred fiber orientation was observed on the fracture surface of the green body. This implies a homogeneous dispersion of chopped fiber in the composite. XRD analysis indicates a complete siliconization of both carbon particles and carbon fiber during liquid silicon infiltration. The flexural strength and fracture toughness increase with chopped fiber ranging from 10vol.% to 30vol.%. This improvement derives from the fiber pullout, fiber debonding as well as crack deflection. The consequent decline at fiber fraction of 40vol.% is resulted from the siliconization of chopped fiber and the increase of residual silicon.

Evolution of chemical and thermal curvatures in thermoset-laminated composite plates during the fabrication process

Residual deformations and stresses formation in the thermoset-laminated composite is a frequently studied subject in the recent years. During fabrication, the laminated composites undergo chemical deformation during cross-linking and thermal deformation while cooling. In thin laminates, due to large displacements and complex evolution of shape, these deformations can only be explained by using nonlinear strain–displacement relationship. In the present article, we calculated together for the first time, the thermal and chemical deformations occurring in carbon/epoxy laminates by considering a nonlinear geometrical approach to understand the evolution of shape and hence residual stresses induced during fabrication process. The effect of fibre fraction on the chemical and thermal deformations is studied as well.

2106 ガラス繊維強化ポリエーテルスルホンの破壊じん性に及ぼす繊維含有率および吸水の影響(G04-2 機械材料・材料加工(2),G04 機械材料・材料加工)

Effect of fiber fraction and water absorption on fracture toughness for glass reinforced polyethersulfone was studied. Fracture toughness of G20 specimen (W_f=20%) is higher than G30 specimen (W_f=30%). The relationship between fracture toughness and fiber weight fraction is not linear. By observing fracture surface and inquiring Acoustic Emission (AE) characteristics of micro-failure process, it is found that primary micro-failure is fiber pulling-out. And it is also found that pull-out of G20 specimen is larger scale than that of G30 specimen. Then, fracture energy of G20 specimen is higher than that of G30 specimen. And this means same tendency in fracture toughness. But fracture toughness is increases by water absorption. It is because of PES resin becoming more ductile by water absorption. Increasing ductility increases fracture energy and fracture toughness.

Parameters Governing Thermal Diffusivity Measurements of Unidirectional Fiber-Reinforced Composites

Limitations in applying the concept of thermal diffusivity to coarse-weave fiber-reinforced composites are examined. Using the flash technique for measuring the apparent diffusivity, the effects of fiber fraction, fiber/matrix thermal conductivity ratio fiber orientation, and specimen length are studied. The conductivity ratio was the major factor governing the thermal behavior of the composite. The fiber fraction was the next most controlling parameter. Specimen length and fiber orientation can be used to modify the behavior of composites.

A study of optimum fibre content in unit composites

The contradictory effects of fibre content on the modulus and on the critical applied stress (initiating bond failure) of unit composites are reviewed for a model consisting of two elastic concentric cylinders. Effect of fibre fraction on the resilience of the model and the optimum fibre percentage defined as the fibre fraction corresponding to maximum value of ‘modulus × critical stress’, has been computed for different hypothetical systems.