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Zhigang Suo's picture

iMechanica is ranked among top engineering blogs

From time to time people ask if I know other websites like iMechanica but focusing on different branches of engineering.  This morning I saw a recently compiled list of Top Engineering Blogs, and was delighted that iMechanica was ranked close to the top.  I'm aware of the widespread cynicisms among iMechanicians about rankings of all kinds.  But, heck, ranking is good if you are ranked high.  As Freeman Dyson would say, being consistent is a weakness of mind. 

Research on the plasticity/damage coupling model using continuum damage mechanics

Currently, i am now attempting to establish a plasticity/damage coupling model using continuum damage mechanics for complex metal structures such as steel pressure vessel, which can be implemented using finite element analysis. The model can predict the progressive failure and damage evolution as well as the crack initiation and propogation due to large plastic deformation of metal structures. Who can give me some suggestion or idea?

pooyan broumand's picture

Smeared crack model in abaqus

Hi ;

I am trying to model a reinforce concrete beam with abaqus  ,I am not familiar with the required parameters needed for the model , I wondered where I can find manuals or detail description of the needed parameteres , and what sort of labartory experiments are needed for this mode (e.g three axial , uniaxial etc.)

Thanks alot

Ken P. Chong's picture

NIST's Technology Innovation Program (TIP) Announces First Competition

ASTRA is delighted to report that the National Institute of Standards and Technology (NIST) is seeking proposals for high-risk research projects to develop innovative technologies for inspecting, monitoring and evaluating critical components of the nation's roadways, bridges, and drinking and wastewater systems. The competition for cost-shared research and development (R&D) support released today is the first to be announced by NIST's newly established Technology Innovation Program (TIP).

Are all 3D-Cracks mix-mode cracks?

I followed this blog with interest for several weeks before I decide to ask my first question. As a newcomer in fracture mechanics, I got confused with a FE-Analysis several days ago, which calcultes the J-Integral of a 3D-crack. Ich transferred the J-Integral calculated using FEM (ADINA) to K (stress intensity factor) and found that the calculated FE-Value is 50% greater than the value acording to the IWM-Methode, which is developed to calculate the K-factors für crack in cylinders.

Uncertainty quantification in mechanics

Modern composite structures have a wide spread in their failure stress.  Advanced multiphysics codes can have a wide range of predicted behavior for nominally the same inputs.  How do we certify the design of such structures or the accuracy of such codes?

Joost Vlassak's picture

Photocatalytic degradation of organic pollutants


School of Engineering and Applied Sciences, Harvard University

Mike Ciavarella's picture


Delft 22 - 24 October


Tom Scarpas     Delft University of Technology, The Netherlands

Patrick Selvadurai     McGill University, Canada

Questions about dislocation souce

As our body, we birth, grow up and dead? Wil the dislocation souce be the same process, if it’s so, what’s the detail process.

(1):the birth of dislocation source

Citation analysis? it is an old story!

I started my research on citation system with a very positve attitude about that. I have read many of scientometrics papers, but now I am completely disappoined! In the report by the International Mathematical Union (IMU) (attached) about citation statistics. I found an interesting sentence! Citation should not be used for evaluation of different papers in two different disciplines. How about different papers from two different sub-disciplines? and even two different  sub-sub-disciplines? and so on!

Zhigang Suo's picture

Memories of IT. Part 1

I finally got around to read Does IT Matter, the 2004 book by Nicholas Carr.  He used the phrase IT (Information Technology) in "its commonly understood sense today, as denoting all the technology, both hardware and software, used to store, process, and transport information in digital form."  He explained, "The meaning of "IT" does not encompass the information that flows through the technology or the talent of the people using the technology."

Sample postdoc research proposals, please !!!

Hi all,

It is very good to see postdoc jobs posted in imechanica .I want to apply for postdoc position in solid mechanics ,however, i have never written a postdoc research proposal.I dont know how it is different from statement of purpose that is required for a graduate research. 

I tried but could not find any sample postdoc research proposal on internet.

I would greatly help if anyone can send me his/her actual or sample postdoc research proposal 

Thanks and Regards,

Sonia Chopra 

On designing dielectric elastomer actuators

Subject to a voltage, a dielectric elastomer can deform substantially, making it a desirable material for actuators. Designing such an actuator, however, has been challenging due to nonlinear equations of state, as well as multiple modes of failure, parameters of design, and measures of performance. This paper explores these issues, using a spring-roll actuator as an example.

Post-Doc Position is avalaible in Bio-Mimetic Adhesive Interfaces

A Post-Doc Position is avalaible in Bio-Mimetic Adhesive Interfaces (EbioAdI) at the University of Mons-Hanaut, Belgium

Supervisor: Prof. Pascal Damman, PhD
University of Mons-Hainaut
Interfaces & Complex Fluids Lab (InFluX)
European Collaborative Research Project (ESF-Eurocores)
Duration : 1 – 3 years
Deadline: 1 September 20088

In short:

Ken P. Chong's picture

STC FY2008 solicitation has cleared

Plans are underway to issue a solicitation for the Science and Technology Centers Program in July 2008. Please visit the STC website for updates:

How to develope a new potential function.

How to develope a new potential function.

For instance, if I want to study a new material system by classical MD, for which the existing potential force fields are not suitable.

I would like to know the standard procedure, how to use the first principle studies/ experimental data and how to select the basic functions...from the experts in this area.

Prasad MVD

How do I run Abaqus 6.7-1 from a DOS Window

Choose a channel featured in the header of iMechanica: 


I am tyring to learn Abaqus for my reserach work. I was easily able to work with  Abaqus CAE. However  I am not able to run Abaqus through a DOS window. Also, the tutorials mention commands like 'abaqus fetch' which do not work on the command line when I input them. It always shows an error saying that 'abaqus' is not a internal or external command,operable program or batch file. 

Can somebody help me with this? Is there any particular part of the Manual or help section that I can read to find out how to do this?

Thermostating only a few atoms in MD

I am trying to apply Berendsen thermostat for CNT. When I choose to leave one third of the tube atoms to evolve freely with out distrubing the momentum, I am unable to acheive the target temperature and further temperature increases gradually over the whole simulation run (even with a thermostat parameter equals to the timestep i.e., like a simple scaling). How it is possible to acheive target temperature,by scaling only a part of atoms, using some scaling value which should actually scales all the atoms momenta.

N. Sukumar's picture

Fortran 90 library for maximum-entropy basis functions

Attached is a tar archive for a Fortran 90 library to compute maximum-entropy basis functions.  I have used the G95 compiler. The manual in PDF is also attached and a html version of the same is also available, which provide details on how to install the code and its capabilities.

Mike Ciavarella's picture

The twin of imechanica in biology and bio-engineering is from MIT !!

OpenWetWare is an
effort to promote the sharing of information, know-how, and wisdom
among researchers and groups who are working in biology &
biological engineering. Learn more about us.

Review papers

One of the most important things every researcher does in the beginning of his introduction to a topic is review process. Most helpful papers in this regard are review papers. Review papers are important. They are primary and best way to understand the value of a work for the societyto award and grant. They help researchers to find out needs of people who use our research and goal functions of scientific society. Help researchers to find out good topics and also good solutions. And the final effect of a research on the society.

Modeling polyurethane

I've started to look into the modeling of polyurethane.  So far I'v found one paper that specifically looks into how to model the mechanical behavior of PU. It describes a possible constitutive model for PU:

Stress-strain behavior of thermoplastic polyurethanes, Qi,H.J.; Boyce, M.C., Mech. Mater. 2005, 37, 8, 817-839

Does someone know of any other resources on the modeling of PU?  Thanks, Andreas

Steffen Brinckmann's picture

Elastic deformation of substrate due to rotation of rigid pillar

Consider a ridig pillar ontop of a elastic substrate. Applying a moment to the pillar will lead to elastic deformation of the substrate. If the pillar is infinitly large in diameter, then this problem is the same as an infinitely sharp crack, considering the symmetry of the crack problem, i.e. there are square root singularities. However, the infinitly large diameter assumtion does not hold if the global rotation of the substrate under the pillar is of interest, because the both sides of the pillar interact.


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