A method to analyze electromechanical stability of dielectric elastomer actuators
This letter describes a method to analyze electromechanical stability of dielectric elastomer actuators. We write the free energy of an actuator using stretches and nominal electric displacement as generalized coordinates, and pre-stresses and voltage as control parameters. When the Hessian of the free-energy function ceases to be positive-definite, the actuator thins down drastically, often resulting in electrical breakdown. Our calculation shows that stability of the actuator is markedly enhanced by pre-stresses.
Research Position at Texas Instruments (Dallas, Texas)
This is a stress modeling position in TI's research
organization Silicon Technology Development (SiTD). The opening is
immediate and the position is filling very fast. Minimum requirement:
MS degree in the following fields: Mechanical Engineering, Physics,
Materials Science or Engineering Mechanics. PhD degree is preferred.
Please email your resume to Jie-Hua (Jeff) Zhao at jhzhao [at] ti.com or
Propagation of instability in dielectric elastomers
When an electric voltage is applied across the thickness of a thin layer of an dielectric elastomer, the layer reduces its thickness and expands its area. This electrically induced deformation can be rapid and large, and is potentially useful as soft actuators in diverse technologies. Recent experimental and theoretical studies have shown that, when the voltage exceeds some critical value, the homogenous deformation of the layer becomes unstable, and the layer deforms into a mixture of thin and thick regions.
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Anecdotal evidence can often serve as a basis for an opinion on the state of science and engineering in the US and abroad. While that evidence is valuable, it is not necessarily representative of national treends. Fortunately, the US government has collected useful information relevant to education, research, and employment within the science and engineering communities and presented it in a series of annual reports.
Why lionize mathematics in science/engineering?
This has reference to (only) the *last paragraph* in Prof. Harry Lewis' recent post, found at: node/1423#comment-2880.
The reason I write the present post is because I always seem to have had a view of inventing, learning, or teaching mathematics that is remarkably at odds with what Prof. Lewis' last paragraph *seems* to imply.
Postdoctoral position at Stanford in materials simulations
Postdoctoral positions are available in the Micro and Nano Mechanics group led by Prof. Wei Cai in the Mechanical Engineering Department at Stanford University. [Link]
Emerging Methods To Understand Mechanical Behavior at 2008 TMS Annual Meeting, New Orleans, LA, March 9-13, 2008
You are cordially invited to submit an abstract to the symposium on “Emerging Methods To Understand Mechanical Behavior” at 2008 TMS annual meeting, New Orleans, LA, March 9-13, 2008.
On the Possibility of Piezoelectric Nanocomposites without using Piezoelectric Materials
In a piezoelectric material an applied uniform strain can induce an electric polarization (or vice-versa). Crystallographic considerations restrict this technologically important property to non-centrosymmetric systems. It can be shown both mathematically and physically, that a non-uniform strain can potentially break the inversion symmetry and induce polarization even in non-piezoelectric dielectrics.
August Workshop on Materials Characterization for Nanoscale Reliability
We invite you to participate in the upcoming Workshop on Materials Characterization for Nanoscale Reliability, to take place 14-16 August, 2007 at the University of Colorado in Boulder, Colorado. Details are posted at http://www.boulder.nist.gov/div853/Nanoscale_Reliability_workshop/index….