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