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N. Sukumar's picture

Maximum entropy coordinates for arbitrary polytopes

In the attached paper, we construct new generalized coordinates for arbitrary polytopes in d-dimensions (polygons and polyhedra in 2- and 3-dimensions, respectively) using the principle of maximum entropy. The paper is to appear in Computer Graphics Forum and will be presented at the SGP'08 Conference in Denmark.  

MichelleLOyen's picture

Web 2.0 and Medicine

I stumbled across this interesting blog post yesterday concerning an upcoming course on medicine via web 2.0.   It appeared quite interesting from several perspectives: first, medicine is often associated with being behind the times on technology but this all looks pretty current, secondly it may be the most comprehensive listing of topics I have seen where web 2.0 is applied to a single discipline, and finally it made me wonder what more we could do with mechanics via web 2.0 beyond just the

Ashfaq Adnan's picture

Effect of Surface Morphology on the Stability of Thin Nanostructures

We have recently studied the atomic scale structural stability of
freestanding wavy gold (Au) nanofilms using molecular dynamics
simulations. In recent years, wavy or patterned structurs have shown great promise for applications in
various emerging technologies including fuel cells
engineering, tissue engineering, biomedical engineering, creation
of counterfeit-resistant documents , nanolithography in microelectronics, optoelectronics, nanomachinesand many others. It is out of question that the
success of these novel applications lies on one crucial factor – the

Arash_Yavari's picture

Energy Balance Invariance for Interacting Particle Systems

This paper studies the invariance of balance of
energy for a system of interacting particles under groups of
transformations. Balance of energy and its invariance is first
examined in Euclidean space. Unlike the case of continuous media,
it is shown that conservation and balance laws do not follow
from the assumption of invariance of balance of energy under
time-dependent isometries of the ambient space. However, the
postulate of invariance of balance of energy under arbitrary
diffeomorphisms of the ambient (Euclidean) space, does yield

Mike Ciavarella's picture

LiquidPub Project: Scientific Publications meet the Web, a project from University of Trento

Liquid Publications: Scientific Publications meet the Web

Some very interesting projects from University of Trento. Changing the way scientific knowledge is produced, disseminated, evaluated, and consumed

A Ph.D.+MSc Position on Brain Surgery Simulation by XFEM and FleXFEM

High Performance Computing MSc+Ph.D. position available at the University of Glasgow on Massively Parallel Brain Surgery Simulation with the extended finite element method (XFEM and FleXFEM)  (University of Glasgow) -- funding body is EPSRC.

One year MSc in HPC in Edinburgh (all costs covered by funding) + 3 year Ph.D.  and access to HecToR, one of the world's largest super-computer, including training with experts in massively parallel simulation (10,000+ processors).

Teng Li's picture

Growing pains of iMechanica

Dear fellow iMechanica users,

Ting Tsui's picture

Ph.D. Candidate Position Available at the University of Waterloo

This is a fully funded research project at the University of Waterloo, Canada. The objective is to construct a PECVD and a UV cure chambers for porous dielectric thin film depositions. In addition to building chambers, the candidate will conduct experiments in thin film fracture and small scale deformation. Please email your CV to

karelmatous's picture

Post-doctoral research associate position

The Computational Science and Engineering Program at the University of Illinois at Urbana-Champaign is seeking highly qualified candidates for one post-doctoral research associate position in the Center for Simulation of Advanced Rockets.

Professor Shih receives Honorary Degree from Brown University



Brown University announced on May 6th 2008 that NUS president Shih Choon Fong is one of the seven honorary degree recipients in this year's commencement. The announcement reads as follows: 


Can the arc-length algorithm for simulating the plastic collapse of solid structures converge using ANSYS ?

For complex composite structures, I have never succeeded in finding the parameter configuration which can reach the convergence using ANSYS. Who can give me some instruction?

Problems of researchers in third world and how IMECHANICA can help them (it is not money).

many researchers in industrial countries think the only problem of third world researchers is money but it is not true. I worked as a researcher for four years in one of this third world countries.

Ansys Failure Criteria

Hello, I am trying to run a laminted composite plate in ansys. I have all the required mechanical properties and the know how to put some of the information. So far, the many trials I did i can't extract the failure criteria results. I want to know whether the plate fails in normal, shear or compression. I appreciate if someone can give me the map of how to get to that result and at what force. what are the step that i have to take in order to get there.



Viscoelasticity in UMAT

I want to model a viscoelastic material using UMAT in Abaqus. I am facing two problems:

Zhigang Suo's picture

Mechanics of Soft Active Materials

At the invitation of David Clarke on behalf of the UCSB/Los Alamos Institute of Multiscale Materials and Structures, I gave the following three lectures:

  1. Large deformation and instability in dielectric elastomers
  2. Large deformation and instability in swelling polymeric gels
  3. Mechanics and electrochemistry of polyelectrolyte gels

The abstracts follow, and the slides are attached at the end of this post.

Cai Shengqiang's picture

University lecturership in Engineering Science in Oxford

Here is a position for University lecturership in Engineering Science(Solid or Structural Mechanics)in association with a Tutorial fellowshiip at Pembroke College. 

Rotating Beams/Frequencies/Errors/Abaqus input file attached

Im trying to model a rotating uniform beam for 12 rotational speeds in Abaqus using c3d20 elements. As expected, "step 1 to step 5" the frequencies increase as the rotational speed is increased. However, for some strange reason, the frequencies stop varying from the fifth speed. I do get warning messages when running the input file but i cant intepret them well since Im new to Abaqus.

I believe the problem is elementary but i cant figure it out. Can anyone review or run the attached input file to let me know what I  am not doing or what exactly is wrong.

Many thanks.

Zhigang Suo's picture

Use RSS feeds to read iMechanica rapidly

People sometimes complain that reading iMechanica takes time.  This is because iMechanica has a large number of pages, and new pages are added frequently.  If you go directly to iMechanica, you have to load individual pages one by one.  


Scaling of fracture strength, fracture energy and toughness is an important issue when it comes to predicting the behaviour of large-scale structures on the basis of laboratory scale measurements. Historically the work of Leonardo da Vinci and Gallileo is well known, followed by the statistical weakest link theory derived by Weibull in 1939. Weibull scaling is a statistical approach assuming instantaneous failure when the weakest link in a material structure fails.


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