Me, Myself, and Solid Mechanics, Or, ES 240 Problem 6 by Stephen Steiner

Overview

This is a blog entry about my background as it pertains to solid mechanics, written in effort to achieve maximum credit for Problem 6 on the ES 240 assignment due Friday, October 5, 2007.

Prior Courses in Solid Mechanics

My prior experience in solid mechanics is limited to half a semester of graduate "Mechanics of Materials" which I took as a listener at MIT in Spring 2005.  As such, much of the material covered in this subject is new to me.

Major History

I majored in Chemistry at the University of Wisconsin--Madison, where I studied synthesis and characterization of organosilicon compounds and the production of aerogels in reduced gravity environments.

I later received my Master's degree in Materials Science and Engineering from MIT, where I researched the synthesis and characterization of carbon aerogels and developed a technique for growing carbon nanotubes directly on carbon aerogels, which eventually lead me into the fundamentals of carbon nanotube growth by chemical vapor deposition.

Strengths and Weaknesses

My strengths include a solid understanding of thermodynamics and atomistic/microscale behavior.  My weaknesses include a generally sparse background in mechanics of materials, things involving kinematics and dynamics, problems that have dashpots and brine tanks, frequently confusing sigma and epsilon, and not being able to tell Prof. Vlassak's lower-case L's, F's, and sometimes alphas from his thetas.

Research Group 

I am currently working towards my PhD in Aeronautics and Astronautics at MIT,
where I work for Prof. Brian Wardle in the Technology Laboratory for Advanced Materials and
Structures (TELAMS).  Our lab focuses on nanoengineering of carbon-fiber composites, in which nanoscale modifications are made to carbon fibers (which are on the order of 7 um in diameter) to improve structural properties of carbon-fiber composites.

My Research Trajectory

The primary focus of my research is to attach vertically aligned carbon nanotubes to carbon fibers and carbon fiber weaves.  By doing so, we hope to achieve a) length-wise interdigitation of carbon fibers in composites (i.e., to "nanovelcro" the fibers together), and b) better interfacing of carbon fibers with matrix polymers as to improve the interlaminar properties of carbon fiber composites.

I am also working on a project for a Formula 1 race car manufacturer who is having problems with consistent performance of reinforced carbon-carbon (RCC) discs used in ther vehicle's clutch.  We have ascertained the origins of their problem are twofold, involving a non-uniform coefficient of thermal expansion and a tribological inadequecy.  I am now trying to characterize the nature of the residual stress in the discs and how this residual stress changes with time and temperature, as well as understand how nanostructural and crystallographic considerations give rise to this residual stress.  Based on these findings, I am developing techniques to work the residual stresses out of the discs, hopefully in time for the upcoming racing season!

In addition to these projects, I am actively pursuing discovery of new materials suitable for catalyzing carbon nanotube growth by chemical vapor deposition.  The goal here is to further understand the underlying physical chemsitry of the nanotube growth process (that is, what does it take to be a nanotube catalyst?) and to engineer catalysts which can aid in CMOS-compatible and chirality-controlled growth of carbon nanotubes.

More about our group is available at http://web.mit.edu/telams. 

How Solid Mechanics Will Play Into My Research

Understanding to characterize, model, and process data from nanoengineered carbon fiber composites, carbon nanotube materials, and the RCC discs I am working with requires a background in solid mechanics, particularly as it pertains to elasticity.

How Solid Mechanics Will Contribute to My Overall Education

I feel solid mechanics will give me better insight into how materials behave, and new inspirations for where novel inventions and paths of research pertaining to nanostructured materials lie.  I am particularly interested in the field of mechanochemistry, which addresses the nature of chemical bonds under mechanical tension and the nature of mechanical forces caused by chemical bond changes.  I feel this subject will complement my background in physical and synthetic chemistry to help me better navigate the field of mechanochemistry.

Additionally, this class will contribute to acquiring the background I will need for my PhD qualifying exams next January.