Blog posts

Spring stiffness of a helical spring

Submitted by Biswajit Banerjee on Tue, 01/31/2012 - 06:19

Once in a while I have to find the stiffness of a spring that I get from the local hardware shop. I usually use a formula that can be found in some books on mechanics of materials.

But the assumptions bother me a bit because the springs that I used usually underwent large deformations and I wasn't sure whether the numbers I was using were correct or not.

To check the formula I compared its predicted k to numbers from Abaqus simulations and found reasonably good results for many situations - but not for soft springs.

Looking for a PhD student

Submitted by pschiavone on Mon, 01/30/2012 - 23:05

education

I'm looking for a PhD student to work in the area of solid mechanics, specifically applied mathematics in linear elasticity using complex variable methods and/or boundary integral equation methods.

I'm a professor in Department of Mechanical Engineering at the University of Alberta in Edmonton, Alberta, Canada (although I am an applied mathematician by training).

You can find out more at: www.mece.ualberta.ca/~schiavone/schiavon.htm

A mathematician's take on "what is light?"

Submitted by Amit Acharya on Mon, 01/30/2012 - 01:26

Attached is an intriguing commentary on the scientific method through an example, written by my good friend, Luc Tartar. The specific example is that of trying to understand what 'light' might be, especially from a mathematician's point of view. The mathematician in this case is an extremely talented one, who also happens to actually understand a whole lot of physics and mechanics.

Simulation blast in soil by Abaqus

Submitted by mo123 on Sun, 01/29/2012 - 11:42

Hello;

H am simulate in ABAQUS a blast in soil.

If in Explicit simulate what is interaction define between TNT & soil?

If simulate by CFD , equation *EOS have not want define.

which way is better?

Thanks.

Mechanics in space (and High School): Lego Man's balloon voyage, or Lego Man in space

Submitted by ikpuri on Sun, 01/29/2012 - 00:47

education

Lego Man in Space

For an interesting news article about the mechanics behind Lego Man's balloon voyage to space, read the Toronto Star article by Mary Ormsby. She writes, "A 1,200-gram weather balloon, the crucial role of gravity, quiver-reducing ropes, Styrofoam’s versatility, burst altitude, a University of Wyoming website and a free software program for shutterbugs were part of the formula Mathew Ho and Asad Muhammad, both 17, used to launch, film and land the patriotic, flag-bearing Lego Man..."

Fracture and contact mechanics for interface problems: a special issue of EFM

Submitted by marco.paggi on Sat, 01/28/2012 - 21:50

research

contact mechanics

Fracture mecahnics

Interface mechanical problems

A Special Issue of Engineering Fracture Mechanics

"Fracture and contact mechanics for interface problems", edited by Marco Paggi, Alberto Carpinteri and Peter Wriggers has just been published:

http://www.sciencedirect.com/science/journal/00137944/80

The selected articles were presented in a Minisymposium of the IV European Conference on Computational Mechanics, Paris, France, 2010.

Giant, voltage-actuated deformation of a dielectric elastomer under dead load

Submitted by Jiangshui Huang on Sat, 01/28/2012 - 14:44

research

Far greater voltage-actuated deformation is achievable for a dielectric elastomer under equal-biaxial dead load than under rigid constraint usually employed. Areal strains of 488% are demonstrated. The dead load suppresses electric breakdown, enabling the elastomer to survive the snap-through electromechanical instability. The breakdown voltage is found to increase with the voltage ramp rate. A nonlinear model for viscoelastic dielectric elastomers is developed and shown to be consistent with the experimental observations.

Published Online: