Zhigang Suo's blog

Fall 2020, Tuesday and Thursday 12:00 pm–1:15 pm.

I’ve just come back from a Winter School on Dielectric Elastomer Transducers, held at Monte Verità, Ascona, Switzerland, 10-16 January 2010.  Lectures were given by various people, covering the theory of electromechanical interaction, design of devices, development of materials, and technologies of manufacturing.  I was asked to give three lectures on the theory.  I attach the slides of my lectures.

Recent experiments have shown that a voltage can induce a large deformation in an elastomer of interpenetrating networks. We describe a model of interpenetrating networks of long and short chains. As the voltage ramps up, the elastomer may undergo a snap-through instability. The network with long chains fills the space and keeps elastomer compliant at small to modest deformation. The network with short chains acts as a safety net that restrains the elastomer from thinning down excessively, averting electrical breakdown.  It appears possible to find a dielectric elastomer capable of giant deformation of actuation.  You can read the paper, or take a look at the slides posted here.

A growing number of mechanicians are entering the field of soft materials, such as polymers, gels, and tissues. While they interact with researchers in technical societies traditionally identified with the field, they also maintain connection with researchers in applied mechanics.

With great pleasure I inform you that Jerrold E. Marsden, of Caltech, are selected to receive the 2010 Thomas K. Caughey Dynamics Award.

With great pleasure I inform you that Yoichiro Matsumoto, of the University of Tokyo, is selected to receive the 2010 Ted Belytschko Applied Mechanics Award.

Harley T. Johnson has just been selected to receive the 2010 Thomas J.R. Hughes Young Investigator Award.

The 2009 ASME Congress starts this weekend.  You can find the schedule of the meetings of all the committees (326KB pdf).  This note lists a few special events. 

Monday, 16 November, 8:00 am to 9:30 am. Plenary Session in Mechanics of Solids, Structures and Fluids

In May 2008, I posted 3 lectures on Soft Active Materials given at UCSB.  I have since given similar lectures on other occasions, but never all three at the same place.  The field has been active.  The lectures have been updated with new items.  I’m now posting the “2nd edition” of these lectures.

• Dielectric elastomers
• Neutral gels
• Polyelectrolyte gels
• pH-sensitive gels 

The slides are posted as delivered.  No effort is made to eliminate repeating slides. 

The number of registered users of iMechanica passed 16,000 early today.  The the number of posts passed 6,900, and that of comments, 12,500. 

iMechanica was founded in September, 2006, with the mission:

1. to use the Internet to enhance communication among mechanicians
2. to pave a way to evolve online all knowledge of mechanics

I quote what I wrote when the number of registered user passed 1000 in early 2007:

With a generous gift from the Haythornthwaite Foundation, the ASME Applied Mechanics Division will award grants to students presenting their own work at the ASME International Mechanical Engineering Congress and Exposition (IMECE 2009).  The grant will reimburse travel expenses and registration fees, up to $1,000 per student, for up to 10 students.

Leonhard Euler has 5 students and 56,850 academic descendents.  They are all listed by the Mathematics Genealogy Project.  Euler himself was a student of Johann Bernoulli, and produced a student named Joseph Louis Lagrange, who in turn produced Fourier and Poisson.  No wonder Euler has so many descendents by now. 

For some time I have been thinking how we can organize a project to trace the genealogy of all mechanicians.  It will be fun.  It may even teach us some history of mechanics. 

You can download a pdf file of this announcement.

The Applied Mechanics Division, of the American Society of Mechanical Engineers, seeks nominations for the awards listed below. All the awards are international.  Neither the nominee nor the nominator need be a member of the ASME.  Further descriptions of the awards are given at http://divisions.asme.org/amd/Honors_Awards.cfm.

In the field of Solid Mechanics, Harvard has a sequence of 5 graduate courses:

• ES 240 Solid Mechanics
• ES 241 Advanced Elasticity
• ES 242r Solid Mechanics:  Advanced Seminar
• ES 246 Plasticity
• ES 247 Fracture Mechanics

The first course goes over linear elasticity, finite element method, vibration, waves, viscoelasticity, as well as some ideas of finite deformation.

I have updated sections of my notes on thermodynamics.  A few thoughts on learning are collected here.  Of our world the following facts are known:

The notes on finite deformation have been divided into two parts: special cases and general theory (node/538). In class I start with special cases, and then sketch the general theory. But the two parts can be read in any order.

For a system in thermal contact with the rest of the world, we have described three quantities: entropy, energy, and temperature. We have also described the idea of a constraint internal to the system, and associated this constraint to an internal variable.

I taught this course at the University of California, Santa Barbara, in Winter 1994, Winter 1995, Spring 1996; at Princeton, Spring 2003; at Harvard, Spring 2004.  The notes posted here are those distributed to the class in Spring 2004.

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