1. Multiscale modeling of Liquid
Crystalline/Nanotube composites
Sharil Patrale
Guided by:
Dr. Gregory Odegard

2. Outline
• Introduction
• Motivation
• Application
• Method
• Accomplishments
• Current work
• Future work

3. 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

4. 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.

5. 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
Material : Liquid Crystal
Polymer LCP 304T40
• Used for electrical
and mechanical parts

6. 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

7. 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

8. Applications
• Vehicle and aircraft components
– Surfacing, engine components
• Sport goods
– Racquets, Helmets, Bikes
• Electronic sensor components
• High temperature applications

9. 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.

10. 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

11. 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

12. 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

13. Eshelby’s Tensor
• Fourth order tensor, Sijkl ( ij = ji)
• Relates the average fiber strain to the average
matrix strain.
c=S T
ij ijkl kl
• Depends on the properties of the matrix material

14. Numerical integration using Gaussian Quadrature:

15. 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.

16. Moduli for various nanotube lengths

17. Aligned fibers

18. Randomly oriented fibers

19. Future work
• Searching for properties of LC polymer (RM-
257)
• Using various fiber/matrix orientations and
aspect ratios
• Optimizing the model

20. Thank you