Zhigang Suo's blog
Chemical potential
A message to the students of ES 242r / ENGM 940
Dear all:
Please post your self-introduction online, following the instruction, but turn in the rest of your homework on paper to your teaching assistants.
Students from Harvard and MIT turn in homework to
Zhen Zhang, (617)-384-7894, zhangz [at] deas.harvard.edu (zhangz[at]deas[dot]harvard[dot]edu), Pierce Hall 406, Skype: flyinskypku.
Pressure
So far we have been mainly concerned with systems of a single independent variable: energy (node/4878). We now consider a system of two independent variables: energy and volume. A thermodynamic model of the system is prescribed by entropy as a function of energy and volume.
The partial derivatives of the function give the temperature and the pressure. This fact leads to an experimental procedure to determine the function for a given system.
The laws of ideal gases and osmosis are derived. The two phenomena illustrate entropic elasticity.
Lecture 6 Channel cracks in thin films
- Various cracks in thin films under tensile or compressive stresses
- Micrographs of cracks in thin films
- A micrograph of a channel crack
- The origin of stress in a film
- Stress in a thin film due to mismatch in the coefficients of thermal expansion
- Stress in film due to bending
- Measure redisual stress using wafer curvature
- Channel crack: initiation vs. steady propagation
- Steady-state energy release rate of a channel crack
- Channel crack in patterned structure
Books, essays and websites that have influenced the development of iMechanica
In this blog entry, I'll maintain a list of books, essays and websites that have influenced me in developing iMechanica. I'll also list my notes on them whenever available. Because iMechanica shares many common problems with other online communities, it is natural that we find solutions discovered by other online communities helpful. At the same time, iMechanica is unique in some respects, and has its own unique problems, so that we cannot adopt any methods or viewpoints without adjustment.
Journal publishers are pioneers of Web 2.0
Eric Mockensturm has just posted a publication agreement proposed by provosts of several universities. In structuring iMechanica, we have tried to avoid the question of open access, and simply asked the question what if all papers are already openly accessible. Many mechanicians have discovered iMechanica, and the registered users have recently passed 1000. Recent discussions of copyright on iMechanica have prompted Eric to post his entry, which has just led to this one.
To the students of ES 242r / ENGM 940
Thank you very much for taking this course. Some of the assignments of
the course will be done on iMechanica. The main purposes of these assignments are
- to expose students to resources for life-long learning, and
- to facilitate interactions among students who are taking the course from three campuses (Harvard, MIT and Nebraska).
Please take the following quick steps now.
A field of material particles vs. a field of markers
In continuum mechanics, it is a common practice to view a body as a field of material particles, so that the continuum mechanics is phrased as an algorithm to determine the function x(X, t), where X is the name of a particle, and x is the place of the particle at time t.
Flip test: imagine continuum mechanics as a revolutionary idea
Let's say the world has only e-books, then someone introduces this technology called 'paper.' It's cheap, portable, lasts essentially forever, and requires no batteries. You can't write over it once it's been written on, but you buy more very cheaply. Wouldn't that technology come to dominate the market?