Blog posts

A summary of my Ph.D. study

Submitted by Jinglei Yang on Sat, 03/03/2007 - 06:07

research

an interesting puzzle: multiscale mechanics

Submitted by Henry Tan on Fri, 03/02/2007 - 21:06

Tan's hot topic series

an interesting puzzle for fun:

Lame’s classical solution for an elastic 2D plate, with a hole of radius a and uniform tensile stress applied at the far field, gives a stress concentration factor (SCF) of two at the edge of the hole. This SCF=2 is independent of the hole radius.

Consider what happened to this concentration factor if the radius a approaches infinitely small. The SCF is independent of a, so it remains equal to two even when the hole disappears.

Three-dimensional anisotropic elasticity - an extended Stroh formalism

Submitted by Jim Barber on Fri, 03/02/2007 - 14:23

research

Stroh formalism

anisotropic elasticity

Tom Ting and I have recently developed a method of extending Stroh's anisotropic formalism to problems in three dimensions. The unproofed paper can be accessed at http://www-personal.umich.edu/~jbarber/Stroh.pdf .

Quasi-continuum orbital-free density-functional theory : A route to multi-million atom electronic structure (DFT) calculation

Submitted by Vikram Gavini on Fri, 03/02/2007 - 00:45

research

materials modeling

materials and mechanics

quasi-continuum theory

density functional theory.

I would like to share the research work I have been pursuing over the past four years. I believe, through this forum, I will be able to reach researchers with various backgrounds and expertise. Suggestions and comments from members will be very useful. I am also attaching links to preprints of manuscripts describing this work. Please follow these links:

http://www-personal.umich.edu/~vikramg/academic/Preprints/QC-OFDFT.pdf

Multi-Axial Failure Models for Fiber-Reinforced Composites

Submitted by Ashkan Vaziri on Wed, 02/28/2007 - 21:21

The increasing use of fiber-reinforced composites accentuates the need for developing multi-axial fatigue failure models for these materials. In this article (attached), we proposed several multiaxial fatigue failure models for fiber-reinforced composites considering the contribution of mean and cyclic normal stress/strain and shear stress/strain at the plane of failure and examined their capability for predicting the fatigue life of the E-glass/epoxy composite materials.

Lecture 9 Interfacial fracture

Submitted by Zhigang Suo on Wed, 02/28/2007 - 18:14

Williams singularity
Energy release rate
Mode angle
Stress oscillation
Small scale contact
Example 1: A small crack on the interface
Example 2: Thin film debonding
Interfacial fracture energy
Four-point bend specimen
Double-cantilever beam
The use of the interfacial fracture energy

Computational or Analytical?

Submitted by Roozbeh Sanaei on Wed, 02/28/2007 - 11:28

Computational or Analytical?

Once you can describe a problem analytically, you should be able to solve the problem straightforward. Moreover, bookkeeping of the related variables is rather easy, enabling you to model your problem in an rather easy fashion. (During my undergraduate courses, I used to check my assignents by Excel). However, implementing such a strategy in software involves a certain amount of problem directed programming - i.e. your code may be valid for a given problem only.