Skip to main content

Blog posts

Size-dependent creep behavior of plasma-enhanced chemical vapor deposited silicon oxide films

Submitted by Xin Zhang on

The time-dependent plastic deformation (creep) behaviors of both the as-deposited and annealed plasma-enhanced chemical vapor deposited (PECVD) silicon oxide (SiOx) films were probed by nanoindentation load relaxation tests at room temperature. Our experiments found a strong size effect in the creep responses of the as-deposited PECVD SiOx thin films, which was much reduced after rapid thermal annealing (RTA). Based on the experimental results, the deformation mechanism is depicted by the "shear transformation zone" (STZ) based amorphous plasticity theories. The physical origin of the STZ is elucidated and linked with the shear banding dynamics. It is postulated that the high strain gradient at shallow indentation depths may be responsible for the reduction in the stress exponent n=∂log(strain rate)/∂log(stress), characteristic of a more homogenous flow behavior.

The first course in continuum mechanics

Submitted by shaofanli on

In response to Zhigang's forum topic on the first course in continuum mechanics, it is so happened that I am also teaching a continuum mechanics course this semester. I shall list our continuum mechanics course outline taught here in Berkeley.

Berkely has its tradition and its special flavour on Continuum Mechanics. The history goes back to Paul Naghdi, Tom Hughes, Jerry Marsden, Juan Simo, David Bogy, Coby Lubliner, Bob Taylor, Karl Pister, James Casey, Geroge Johnson, and some others.

Mechanisms of reversible stretchability of thin metal films on elastomeric substrates

Submitted by splacour on

Gold films on an elastomeric substrate can be stretched and relaxed reversibly by tens of percents. The films initially form in two different structures, one continuous and the other containing tri-branched microcracks. We have identified the mechanism of elastic stretchability in the films with microcracks. The metal, which is much stiffer than the elastomer, forms a percolating network.

We Are Mechanicians

Submitted by Zhigang Suo on

In early days of Applied Mechanics News, I encountered a practical problem. How do we call ourselves? I began with a phrase "people in the international community of applied mechanics". The phrase is inclusive and descriptive, but is too long, too timid and too clumsy. It is like calling entropy "the logarithm of the number of quantum states". I have also heard the phrase "mechanics people", which I don't like either. It sounds too folksy, like calling a gynecologist a women's doctor.

What can mechanicians do in fusion research?

Submitted by Yixiang Gan on

More than fifty years ago, people realized that we can use fusion for energy, but the problem remains where and how to keep a plasma of 100 million degrees centigrade.

For TOKAMAK, one of the approaches to use the fusion power, now comes the news: "On 21 November, Ministers from the seven ITER Parties came together to sign the agreement to establish the international Organization that will implement ITER."

EM 397 Thin Film Mechanics Term Paper

Submitted by Rui Huang on

Each student completes a term paper of selected topics that (a) addresses a phenomenon in thin film materials, and (b) involves analyses using mechanics. The project contributes 25% of the grade, distributed as follows:

  • 5%: November 30 (Thursday). Post your title and abstract in iMechanica, formated as below
  1. Title (EM 397 Term Paper: e.g., Dislocations in Epitaxial Thin Films).
  2. Tags (EM 397, Fall 2006, University of Texas at Austin, thin films, term paper)
  3. Body: (i) Describe the phenomenon. (ii) Explain how mechanics is relevant. (iii) Cite at least 1 journal article.
  • 10%: December 12 Tuesday (2:00-4:00 pm). 30 minute presentation. Use power point slides.
  • 10%: December 18 Monday.

The Future of Cell Phone?

Submitted by Teng Li on

Here is one answer from Nokia.


Nokia 888 communicator, a concept design which recently won the Nokia's Benelux Design Award. It uses liquid battery, flexible touch display, speech recognition, touch sensitive body cover which lets it understand and adjust to the environment. It has a simple programmable body mechanism so that it changes forms in different situations. Don't forget to enjoy a video demo of this cell phone of future.
Yet one more future application of flexible electronics, it's clear there're great mechanics and materials challenges in making electronic devices flexible. It will be great mechanicians can help accelerate the advance of this emerging technology.

The 2nd International Conference on Heterogeneous Material Mechanics (ICHMM-2008)

Submitted by Changguo Xue on

ICHMM 2008 seeks dissemination of recent, leading edge research results as well as in-depth discussions of future directions in the challenging subject of heterogeneous material mechanics. Sessions in the Huangshan International Hotel will focus on recent original research developments, while invited panel discussins in the subsequent Huangshan Mountain retreat aim to stimulate future research directions.

Co-Chairs

J. Fan, Alfred University, USA and Chongqing University

The topics of interest are: