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The 2008 Melosh Medalists

On Friday, April 25th, 2008, the 20th Annual Melosh Competition for the Best Student Paper in Finite Element Analysis was held at Duke University.  The competition resulted in a tie between Ludovic Chamoin (of the University of Texas, Austin) and Irina Kalashnikova (of Stanford University).   Here is a picture of the 2008 Melosh Medalists with the judges, Leo Franca and Nicolas Moes:


Ying Li's picture

Poisson's ratio changable of carbon nanotube sheet

Here is a recent work on the Poisson's ratio of carbon nanotube sheet [1]. From the experimental results, the researchers found that the Poisson's ratio could change from 0.06 to -0.20 as the content of MWNTs increasing from 0~100%. The interesting zero Poisson's ratio and auxetic materials were thus found.  

Ref. [1] Sign Change of Poisson's Ratio for Carbon Nanotube Sheets. Science 25 April 2008: 504-507

Ying Li

Layered Material.

I want to get some information about layered material and its property and nutural plane in bi metal plate while bending.

Post-doc position on Multiscale Simulations of Cell Contact and Adhesion

A post-doc position on multiscale simulation of cell contact and adhesion shall be available this coming Fall at UC Berkeley. We are seeking for a person who has experience and background on finite element computations, especially in cell contact/adhesion modeling and simulation or finite deformation simulations.

Anyone who is interested in the position please send an email, resume, and reference to

Grand Challenges For Engineering

The US National Academy of Engineering has published a list of Grand Challenges for Engineering. Ths US National Committee on Theoretical and Applied Mechanics is interested in developing a discussion on the implications of these Grand Challenges to the Mechanics community.

cbrinson's picture

New Book on Polymers and Viscoelasticity

I wish to inform the imechanica community about my recent book,  Polymer Engineering Science and Viscoelasticity, Springer, 2008. THe book starts at the beginning and contains both the physics of polymers and the mathematics of viscoelasticity. It is also unique in the history of mechanics in being the (first ever?) father-daughter book. Those interested in polymer mechanics may find this a useful resource! It may be found in your library or further information can be found here

2014 US National Congress on Theoretical and Applied Mechanics

The US National Committee on Theoretical and Applied Mechanics is seeking proposals from US institutions interested in hosting the 2014 US National Congress on Theoretical and Applied Mechanics. If you are interested, please contact K. Ravi-Chandar: for more information. 

PhD Position: Solid Mechanics/Biomechanics at KTH-Stockholm

PhD Position: Solid Mechanics/Biomechanics at KTH-Stockholm

A four to five-year PhD position focusing on the analysis of multi-scale phenomena in diseased blood vessels including atherosclerotic plaques has recently been opened at KTH Solid Mechanics. The position is fully supported by the Swedish Research Council.

Micro-scale compression testing for hydrogel microspheres between two rigid plates

I am a last year Ph.D student at University of Toronto. During my study, I developed MEMS force sensor-based micro-scale compression testing for micrometer-sized spherical biomaterials. I applied this system for mechanical properties characterization of polymeric hydrogel microsphere for drug delivery.

Crack Propagation using XFEM ( What happens to dof's corresponding to enriched nodes)

I am working on crack propagation . I am trying to figure what factors should be taken into account when the crack is being propagated using XFEM.

I am especially interested to know what happens to the additional dof's corresponding to enriched nodes. Once the crack is propagated and crack tip is at new location , we add new dof's corresponding to enrichment functions , but what happens to the information stored by the dof's of previous enriched nodes,do we forget them altotgether , or do we map it to the new enriched nodes?

Masayuki Wakamatsu's picture

Crack Length in Cohesive Element (ABAQUS vr 6.7.1) in pure MODE I case

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Help! imechanica!

This might not be a smart question to ask, but if any of you can help me, it'd be great.

 I have a DCB (sandwitch specimen) with a cohesive element in the middle. Studying pure Mode I case, displacement is applied at the end of the DCB. Cohesive element works great (it fails when one reaches max separations).  But I am having a difficulity in extracting crack length (i.e. length of failed cohesive element) vs time step. I looked for Damage and Status commend, but it's not promising.  (I'm pretty new to ABAQUS....)

Evalauation of shape functions for nodes on the boundary in weak form

I am doing my Masters Thesis on Application of Mesh free method on Laser cutting.

I am using Radial point interpolation method for evaluation of the shape functions.I have successfully applied it to the interior nodes and I am using weak form for the nodes on the natural boundaries.

I am facing difficulty in application of numerical integration for the functions in the weak form .I am using circular subdomain and applying Gauss quadrature formula for the numerical integration.

I would be glad if I can get some help in this regard.

Thank you

New Graduate Textbook on Micromechanics and Nanomechanics

World Scientific Pub. Co. will soon (2008 Winter) publish a new graduate textbook on Micromechanics and Nanomechanics.  The book is based on a lecture notes that have been used in Berkeley for seven years. Reading of book requires minimum knowledge of continuum mechanics and mathematics, and the book is intended for the first year graduate students as well as those practitioners who have no time to read the literature for self-study.

Mike Ciavarella's picture

A EUROPEAN web portal to discuss NAE's “Grand Challenges” impact in EUROPE

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We are planning to set a WEB portal to discuss

1) the example and the role of an Academy of Engineering to find the correct blend of credentials and consensus to set research needs

Mike Ciavarella's picture

More replies to Yavari, fractals, strongly emotional disputes, and what really leads to Nobel prize

Dear Yavari

I have promised more replies on Mandelbrot, fractals, strongly emotive discussions in journals, and here is a coincise statement, which I take from a Nobel prize, prematurely passed away last year.  I think it has a lot to teach (including the kind of attitude that leads to Nobel prize, i.e. close to no human weakness), you will recognize the real name of the "Caesar" in this book is somebody with a 58 pages CV on his web site, most likely.

For a better idea of fractals, read please the other attachment.



The maximum receptor-ligand bond spacing to ensure cell adhesion in ligand-coated substrates

Recent experiments by Arnold et al. (ChemPhysChem, vol. 5, 2004, p383 ) revealed that a distance of less than 58-73 nm between receptor-ligand bonds is necessary to ensure focal adhesion in cells adhering to ligand-coated substrate. An elegant solution to this problem is supplied by Lin, Inamdar, and Freund.

Is the limit of stress intensity factors "1" when the crack length is close to "0"?

I have read some papers about fracture mechanics of functionally graded materials. I find there are different results for the stress intensity factors when the crack length is close to "0" . In some papers the values of stress intensity factors are "1" when the crack length is close to "0" , but in other papers the values of stress intensity factors are not "1". I obtain the stress intensity factors is "1" when the length of crack is close to "0". I hope to get the explaination about the results.Thanks a lot.

thermal barrier systems

Dear sir,      

           In thermal barrier systems it is seen that Zirconia is extensively used  as  coating.May  I know  what  properties of it enable it to be  leading material for TBC.What  are the  other recent materials used in this system?

to model creep behavior in ABAQUS


I have different stress strain curves at different hours (1hr, 10hr, 100hr).  for a constant stress, the strain increases with increase in number of hours(creep)

They look like stress-strain curves at different strain rates.

now I want to define a material card with these curves with above mentioned number of hours.

I kindly request you to suggest me a CARD in ABAQUS which takes care of this behavior.

Toupin-type Decay and Saint-Venant's Principle

Saint-Venant's Principle is important in the theory and application of elasticity and its proof or formulation is a major attraction  for authors. Among others,Toupin's Theorem plays  the most influential  role in the history of  development  concerning Saint-Venant's Principle.


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