Design Method for Braiding Process and Structure Parameters of Three Dimensional Two-Step Tubular Braided Preform

2010 ◽  
Vol 150-151 ◽  
pp. 1613-1616
Author(s):  
Yan Gao ◽  
Jia Lu Li
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Design Method ◽  
General Structure ◽  
Three Dimensional ◽  
Structure Parameters ◽  
Fiber Volume ◽  
General Methodology ◽  
Properties Of Composites

The properties of composites reinforced by three dimensional braided preform are determined by braiding structure significantly. The main objective of this paper is to develop a general methodology for the determination of the design and analysis of three dimensional two-step braided tubular preform. The arrangement pattern of axial yarns with various finenesses is derived for the uniform braiding structure of preform, which offers a possibility for achieving preferable interior structures of braided tubular preforms. Then, the general structure parameters, including the interrelation between surface braiding angles and interior braiding angles and the fiber volume fraction, are investigated in some detail. The results derived from this paper can provide a useful method for the design of 3D two-step tubular braided preform.

Determination of the Directional Dependent In-Plane Thermal Conductivity of K63B12 Pitch-Fiber/Epoxy Composite

2004 ◽  
Author(s):  
Jessica N. McClay ◽  
Peter Joyce ◽  
Andrew N. Smith
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Fiber Composite ◽  
Fiber Volume ◽  
State Technique ◽  
Fiber Composite Materials

Measurements of the in-plane thermal conductivity and the directional dependence of Mitsubishi K63B12 pitch-fiber/Epoxy composite from Newport Composites are reported. This composite is being explored for use in the Avanced Seal Delivery System for effective thermal management. The thermal conductivity was measured using a steady state technique. The experimental results were then compared to a model of the thermal conductivity based on the direction of the fibers. These estimates are based on the properties of the constituent materials and volume of fibers in the sample. Therefore the density and the fiber volume fraction were experimentally measured. The thermal conductivity is clearly greatest in the direction of the fibers and decreases as the fibers are rotated off axis. In the case of pitch fiber composite materials, the contribution of the fibers to the thermal conductivity dominates. The experimental data clearly followed the correct trends; however, the measured values were 25% to 35% lower than predicted.

Simulation for Composite Forming Infusion from both inside and outside at same Time

2013 ◽  
Vol 329 ◽  
pp. 153-156
Author(s):  
Wei Xiao Du ◽  
Zhong De Shan ◽  
Feng Liu
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Fiber Volume ◽  
New Approach ◽  
High Fiber ◽  
Composite Forming ◽  
Filling Time ◽  
Infusion Method

Impregnation quality is vital to the whole composite. To improve it a new approach-infusion from both inside and outside at same time is supposed. Some comparison simulation studies, based on PAM-RTM software, are performed in this paper about the new composite forming method and traditional infusion method including flow behavior and filling time. Filling time via the two methods are compared, and the following results are obtained-It takes less time to fill the mold with infusion from both inside and outside at same time than traditional one; higher fiber volume fraction is, more favorable the new forming method is. The new infusion method is proved to be an effective and novel forming method about parts with high-thickness or high fiber content in composite forming area. The results will contribute to researches on the whole composite forming and bring prospect to provide more usages of three dimensional composites in high rank field.

A New Theory for the Debonding of Discontinuous Fibers in an Elastic Matrix

1989 ◽  
Vol 170 ◽  
Author(s):  
Christopher K. Y. Leung ◽  
Victor C. Li
Keyword(s):  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Interfacial Strength ◽  
Fiber Composites ◽  
Short Fiber ◽  
Fiber Volume ◽  
Physical Reason ◽  
Pull Out

AbstractThe mechanical properties of fiber composites are strongly influenced by the debonding of fibers. When an embedded fiber is loaded from one end, debonding can occur at both the loaded end and the embedded end. Existing theories neglect the possibility of debonding from the embedded end and are thus limited in applications to cases with low fiber volume fraction, low fiber modulus, high interfacial strength/interfacial friction ratio or short fiber length. A new twoway fiber debonding theory, which can extend the validity of one-way debonding theories to all general cases, has recently been developed. In this paper, the physical reason for the occurrence of two-way debonding is discussed. The limit of validity for one-way debonding theories is considered. One-way and two-way debonding theories are then compared with respect to the prediction of composite behaviour. The determination of interfacial parameters from the fiber pull-out test will also be described.

A new model for the determination of optimum fiber volume fraction under multi-axial loading in polymeric composites

2018 ◽  
Vol 28 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Fathollah Taheri-Behrooz ◽  
Mahmood Mehrdad Shokrieh ◽  
Hamidreza Sokhanvar
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Axial Loading ◽  
Polymeric Composites ◽  
Fiber Volume ◽  
New Model

Evaluating the effect of variable fiber content on mechanical properties of additively manufactured continuous carbon fiber composites

2020 ◽  
pp. 073168442096321
Author(s):  
Dakota R Hetrick ◽  
Seyed Hamid Reza Sanei ◽  
Charles E Bakis ◽  
Omar Ashour
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Content ◽  
Fiber Volume ◽  
Transverse Strength ◽  
Continuous Carbon Fiber ◽  
3D Printed ◽  
Properties Of Composites

Fiber volume fraction is a driving factor in mechanical properties of composites. Micromechanical models are typically used to predict the effective properties of composites with different fiber volume fractions. Since the microstructure of 3D-printed composites is intrinsically different than conventional composites, such predictions need to be evaluated for 3D-printed composites. This investigation evaluates the ability of the Voigt, Reuss, and Halpin–Tsai models to capture the dependence of modulus and strength of 3D-printed composites on varying fiber volume fraction. Tensile coupons were printed with continuous carbon fiber-reinforced Onyx matrix using a Markforged Mark Two printer. Specimens were printed at five different volume fractions with unidirectional fibers oriented at either [Formula: see text] to obtain longitudinal, shear, and transverse properties, respectively. It is shown that the Voigt model provides an excellent fit for the longitudinal tensile strength and a reasonable fit for the longitudinal modulus with varied fiber content. For the transverse direction, while the Reuss model fails to capture the transverse modulus trend, the Halpin–Tsai model provides a reasonable fit as it incorporates more experimental parameters. Like conventional composites, addition of fibers degrades the transverse strength, and the transverse strength decreases with increasing fiber volume fraction. The shear modulus variation with fiber content could not be fitted reasonably with either Halpin–Tsai model or Reuss model.

Relation of 2D Permeability and Preform Structure Parameters

2011 ◽  
Vol 306-307 ◽  
pp. 1678-1682
Author(s):  
Jin Hua Jiang ◽  
Nan Liang Chen
Keyword(s):  
Significant Influence ◽  
Linear Density ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Structure Parameters ◽  
Capacitive Sensors ◽  
Two Dimensional ◽  
Flow Front ◽  
Fiber Volume ◽  
Fabric Structure

In this paper the influence of parameters of fabric preforms on permeability is described. The two-dimensional (2D) permeability has been determined continuously in a matched metal tool incorporating capacitive sensors with LabView. Beforehand, the glassfiber plain, twill, satin weave textile has been thoroughly evaluated to determine the permeability behavior of the textile in dependence on the fiber volume fraction. The paper reveals the significant influence of the fabric structure, and yarn linear density on the permeability values K1 and K2, the flow front ellipse shape, and the anisotropy of preforms.

Mechanical Properties of Interface Layers in SiC/TiAl Composite

2021 ◽  
Vol 1016 ◽  
pp. 151-155
Author(s):  
Keizo Hashimoto ◽  
Jiang Jin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Volume ◽  
Sic Fiber ◽  
Pull Out ◽  
Interface Layers ◽  
Properties Of Composites

Although metal matrix composites (MMC) for the high temperature structural material have been investigated extensively for many years, applications of MMC have been still limited. Among many combinations between the ceramic fibers and the matrix materials, combination of SiC fiber and TiAl based intermetallic compounds has been expected to be one of the best combination, since both SiC fiber and TiAl have demonstrated the capabilities of the low density heat resistant materials. SiC fiber reinforced TiAl composites have been successfully fabricated using hot press method. Optimum temperature and pressure have been determined. SiC/TiAl composite having relatively low fiber volume fraction shows nearly an ideal elastic property applying the law of mixture. Effects of interface layers on the mechanical properties of composites have been studied in detail. Micro-indentation on a single fiber was carried out to examine the pull out strength of SiC fiber quantitatively. Estimated shear stress on the interface was 145-195MPa, those values are quite reasonable since the tensile strength of TiAl matrix was 420MPa and the maximum shear stress would be the half of tensile strength according to Schmid law. Three-point bending tests have been carried out to evaluate the mechanical properties of composites. Fiber volume fraction 8.9% specimen shows ideal bending stiffness compare with the calculated values based on the low of mixture. Reaction layers and the interface between SiC fiber and TiAl have been analyzed by SEM-EDS and XRD. At least two or more reaction layers have been identified. These reaction layers can be explained based on the Si-Ti-C ternary equilibrium phase diagram at 1373K. Optimum conditions of interface structure will be discussed

Effect of Fiber Volume Fraction on Thermal Conductivity of a Woven-Mat Composite Lamina

2005 ◽  
Author(s):  
Hossein Golestanian
Keyword(s):  
Thermal Conductivity ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Fiber Volume ◽  
Element Analysis ◽  
Fiber Mats ◽  
The Common ◽  
Thermal Conductivities

Models are presented for the determination of thermal conductivity of a composite lamina with woven fiber mats. In analyzing the cure cycle of a composite part, the common practice has been to use weight-averaged thermal properties. The limitation of this approach becomes apparent when one finds that thermal conductivity calculated for fiberglass/epoxy composite is very close to thermal conductivity of carbon/epoxy composite. This happens for composite parts with the same fiber volume fraction. In weight-average formulations the effect of fiber thermal conductivity is overshadowed by the density of the constituents. To overcome this problem, one needs to take another approach. In this investigation finite element analysis is performed to determine thermal conductivities of fiberglass/epoxy and carbon/epoxy composite lamina. The resulting thermal conductivities are different for the two composite types. These results make more physical sense since thermal conductivity of carbon fiber mat is much higher than that of fiberglass mat.

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