Date post: | 24-May-2015 |
Category: |
Design |
Upload: | sharilmail |
View: | 261 times |
Download: | 1 times |
Multiscale modeling of Liquid Crystalline/Nanotube composites
Sharil Patrale
Guided by:
Dr. Gregory Odegard
Outline
• Introduction• Motivation• Application• Method• Accomplishments• Current work• Future work
Introduction
• Composite material is a material composed of two or more distinct phases.
• Types of composites– Metal matrix composites– Ceramic matrix composites– Polymer matrix composites
Polymer Matrix Composites
• Material consisting of a polymer matrix combined with a reinforcing phase of fibers.
• Exhibit high strength and stiffness
• Light in weight.
• Show directional strength properties
• Carbon fiber reinforced polymer composites.
Liquid crystalline polymer
• Obtained by dissolving a polymer in solvent or heating to its melting point
• High mechanical strength
at high temperatures– High strength to weight ratio
when combined with
nanotubes
• Used for electrical
and mechanical parts
Material : Liquid Crystal Polymer LCP 304T40
Why Carbon Nanotubes?
• Very high strength-Stronger than the sp3 bonds in Diamond
• High stiffness
• High thermal conductivity
• Extremely light weight-about 1/5th of the weight of steel
Motivation
• Ability of LC molecules (matrix) to be oriented in preferred direction using electric or magnetic fields
• Surface tension aligns the nanotubes
• Resulting mechanical and thermal properties
• Vehicle and aircraft components– Surfacing, engine components
• Sport goods– Racquets, Helmets, Bikes
• Electronic sensor components
• High temperature applications
Applications
The Research
• To develop the nano-composite forming process.
• To optimize the mechanical and thermal properties of the nano-composites.
→ To implement a mathematical modeling approach for efficiently predicting the composite’s mechanical properties.
Mechanical/elastic properties
• E1 – longitudinal young’s modulus• E2 – transverse young’s modulus• v12 – longitudinal poisson’s ratio• v23 – transverse poisson’s ratio• G12 – longitudinal shear modulus
Micromechanics
• Analysis of a composite at the level of its individual constituent
• Can predict the multi-axial properties of anisotropic composites
• Typically based on continuum mechanics– Response of anisotropic materials
→ Focus on Mori-Tanaka modeling approach
Mori-Tanaka modeling approach
• Calculating the average internal stress in the material
• More efficient than any other method with anisotropic matrix
• Predicting elastic properties as a function of– Nanotube orientation– LC orientation– Nanotube volume fraction– Interfacial conditions
Eshelby’s Tensor
• Fourth order tensor, Sijkl (𝛔ij = 𝛔ji) • Relates the average fiber strain to the average
matrix strain.𝛆ijc = Sijkl 𝛆klT
• Depends on the properties of the matrix material
Numerical integration using Gaussian Quadrature:
Accomplishments
• Mathematical model to determine elastic properties of LaRC-SI/nanotube composite.
• Relationship between various moduli and fiber volume fractions at different aspect ratios.
• Model to calculate Eshelby’s tensor for anisotropic matrix
• Corresponding graphs are shown.
Moduli for various nanotube lengths
Aligned fibers
Randomly oriented fibers
Future work
• Searching for properties of LC polymer (RM-257)
• Using various fiber/matrix orientations and aspect ratios
• Optimizing the model
Thank you