Effect of the Carbon Nanotube Distribution on the Thermal Conductivity of Composite Materials

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Iman Eslami Afrooz ◽  
Andreas Öchsner
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Volume ◽  
Element Analysis ◽  
The Matrix ◽  
Good Agreement

Finite element analysis has been employed to investigate the effect of carbon nanotubes (CNTs) distribution on the thermal conductivity of composite materials. Several kinds of representative volume elements (RVEs) employed in this study are made by assuming that unidirectional CNTs are randomly distributed in a polymer matrix. It is also assumed that each set of RVEs contains a constant fiber volume fraction and aspect ratio. Results show that randomness—the way in which fibers are distributed inside the matrix—has a significant effect on the thermal conductivity of CNT composites. Results of this study were compared using the analytical Xue and Nan model and good agreement was observed.

The Estimation of Thermal Conductivity for Alumina-Epoxy Composite Material with High Filling Volume Fraction

2014 ◽  
Vol 918 ◽  
pp. 21-26
Author(s):  
Chen Kang Huang ◽  
Yun Ching Leong
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Composite Materials ◽  
Physical Model ◽  
Electron Scattering ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
The Matrix ◽  
Transport Theorem ◽  
Good Agreement

In this study, the transport theorem of phonons and electrons is utilized to create a model to predict the thermal conductivity of composite materials. By observing or assuming the dopant displacement in the matrix, a physical model between dopant and matrix can be built, and the composite material can be divided into several regions. In each region, the phonon or electron scattering caused by boundaries, impurities, or U-processes was taken into account to calculate the thermal conductivity. The model is then used to predict the composite thermal conductivity for several composite materials. It shows a pretty good agreement with previous studies in literatures. Based on the model, some discussions about dopant size and volume fraction are also made.

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.

Effect of Nanocomposite Microstructure on Stochastic Elastic Properties: An Finite Element Analysis Study

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
Seyed Hamid Reza Sanei ◽  
Randall Doles ◽  
Tyler Ekaitis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Properties ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Microstructural Feature ◽  
Stochastic Response ◽  
Fiber Volume ◽  
Element Analysis ◽  
Analysis Study

This paper addresses the effect of microstructure uncertainties on elastic properties of nanocomposites using finite element analysis (FEA) simulations. Computer-simulated microstructures were generated to reflect the variability observed in nanocomposite microstructures. The effect of waviness, agglomeration, and orientation of carbon nanotubes (CNTs) were investigated. Generated microstructures were converted to image-based 2D FEA models. Two hundred different realizations of microstructures were generated for each microstructure type to capture the stochastic response. The results confirm previously reported findings and experimental results. The results show that for a given fiber volume fraction, CNTs orientation, waviness, and agglomeration result in different elastic properties. It was shown that while a given microstructural feature will improve the elastic property, it will increase the variability in the elastic properties.

Determination of fiber volume fraction in a cured laminate

2021 ◽  
pp. 002199832110112
Author(s):  
Qing Yang Steve Wu ◽  
Nan Zhang ◽  
Weng Heng Liew ◽  
Vincent Lim ◽  
Xiping Ni ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Evaluation Method ◽  
Volume Fraction ◽  
Matrix Material ◽  
Volume Ratio ◽  
Gravimetric Analysis ◽  
Fiber Volume ◽  
Laser Ultrasonic ◽  
The Matrix

Propagation of ultrasonic wave in Carbon Fiber Reinforced Polymer (CFRP) is greatly influenced by the material’s matrix, resins and fiber volume ratio. Laser ultrasonic broadband spectral technique has been demonstrated for porosity and fiber volume ratio extraction on unidirection aligned CFRP laminates. Porosity in the matrix materials can be calculated by longitudinal wave attenuation and accurate fiber volume ratio can be derived by combined velocity through the high strength carbon fiber and the matrix material with further consideration of porosity effects. The results have been benchmarked by pulse-echo ultrasonic tests, gas pycnometer and thermal gravimetric analysis (TGA). The potentials and advantages of the laser ultrasonic technique as a non-destructive evaluation method for CFRP carbon fiber volume fraction evaluation were demonstrated.

Development of Generalized Plane-Strain Tensors for the Concentric Cylinder

1995 ◽  
Vol 62 (3) ◽  
pp. 590-594
Author(s):  
N. Chandra ◽  
Zhiyum Xie
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Transformation Strain ◽  
Inclusion Problem ◽  
Infinite Domain ◽  
Concentric Cylinder ◽  
Finite Radius ◽  
Fiber Volume ◽  
Thermal Residual Stresses ◽  
The Matrix

A pair of two new tensors called GPS tensors S and D is proposed for the concentric cylindrical inclusion problem. GPS tensor S relates the strain in the inclusion constrained by the matrix of finite radius to the uniform transformation strain (eigenstrain), whereas tensor D relates the strain in the matrix to the same eigenstrain. When the cylindrical matrix is of infinite radius, tensor S reduces to the appropriate Eshelby’s tensor. Explicit expressions to evaluate thermal residual stresses σr, σθ and σz in the matrix and the fiber using tensor D and tensor S, respectively, are developed. Since the geometry of the present problem is of finite radius, the effect of fiber volume fraction on the stress distribution can be easily studied. Results for the thermal residual stress distributions are compared with Eshelby’s infinite domain solution and finite element results for a specified fiber volume fraction.

Study on the In Situ Growth of Carbon Nanotubes for the Reinforcement of Cf/SiC Composite Fabricated by CVI+PIP Process

2013 ◽  
Vol 745-746 ◽  
pp. 582-586 ◽  
Author(s):  
Jian Bao Hu ◽  
Shao Ming Dong ◽  
Xiang Yu Zhang ◽  
Zhen Wang ◽  
Hai Jun Zhou ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Bonding Strength ◽  
Volume Fraction ◽  
Interfacial Bonding ◽  
Mechanical And Thermal Properties ◽  
Fiber Volume ◽  
Pull Out ◽  
Interfacial Bonding Strength

Cf/SiC composites were fabricated through in situ growth of carbon nanotubes (CNTs) on three-dimensional needle-punched carbon fabric via chemical vapor deposition and polymer impregnation and pyrolysis process. The mechanical and thermal properties of the composites were investigated. The flexural strength and fracture toughness were decreased due to the fiber volume fraction loss and much shorter pull-out length of fibers which was caused by the higher interfacial bonding strength between fiber and matrix after the growth of CNTs. Brittle fracture character of CNTs was observed due to the strong interfacial bonding strength between CNTs and matrix. The parallel thermal conductivity and perpendicular thermal conductivity were improved to 14.5% and 8.0% respectively.

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.

Mechanics of Natural Composites

1990 ◽  
Vol 218 ◽  
Author(s):  
Joseph E. Saliba ◽  
Rebecca C. Schiavone ◽  
Stephen L. Gunderson ◽  
Denise G. Taylor
Keyword(s):  
Composite Materials ◽  
Modulus Of Elasticity ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Structural Response ◽  
Sensitivity Study ◽  
Fiber Volume ◽  
Fiber Size ◽  
Natural Composites ◽  
As Stress

AbstractThis study was initiated to investigate the structural response of the bessbeetle to determine potential advantageous ramifications and effects on the optimization of synthetic composite materials. The result of the micromechanics sensitivity study of various parameters are presented. Variables such as fiber size and shape, fiber volume fraction, ratio of modulus of elasticity of fiber over matrix, are changed one variable at a time, and the response quantities such as stress and tranverse modulus are presented.

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