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Einstein's birthday, the PI day

The day before yesterday, Mar. 14 (3.14), was a great date, because Albert Einstein was born at the same day 130 years ago.

I and my wife enjoyed a very good holiday that day in Taipei. Most interestingly, we found a vivid statue of Einstein made by Ju Ming, stood still in front of the Chen-Ping (eslite) bookstore.

We took several photos around this statue. Here I share one of them with you.

An ice block submerged in the water, if the ice melts level of water What will Happen

An ice block submerged in the water, if the ice melts level of water Whatwill be the level of water .

1. Increase

2. Remain Same

3. Decrease

This is my first 2009 article

Now I come here again.

From now on I want to share with you my research experiences and personal opinion on  time dependent quantum system, photonic/sonic crystals, and metamaterials.  I would also like to write some articles on science teaching stuff.

I come from Taiwan. Usually I speak chinese, and have no many oppernituties to practice my English, so I wish someone can help me to improve my English. Thanks !



Pradeep Sharma's picture

Book Review

Micromechanics---loosely speaking, is the study of heterogeneities in materials and its consequences for material or continuum behavior. This encompasses studies of inclusions, dislocations, cracks or more generally defects. A related problem is that of "coarse-graining" or in other words the effective homogenized properties of a heterogeneous material. The latter is a recurring theme in all of physical sciences not just solid mechanics. Micromechanics, a formidable subject by all means, dominated a substantial part of the history of solid mechanics. Several of our Timoshenko awardees have been associated with this subject, e.g. Eshelby, Hill, Keller, Irwin, Rice among others.

composite material in ansys workbench 11


I want to model a composite material (e.g. frp) elbow in ansys workbench 11. How can I define the material?

thanks a lot


Alejandro Ortiz-Bernardin's picture

Near-incompressible analysis

Hello all,

I am studying some simple finite elements for 2d near-incompressible analysis. Particularly, I am interested in the MINI element. It is basically a 3-node triangle element with nodal pressure and displacement degree of freedoms enriched by a bubble function. Could someone that has some experience with these elements point me out about advantages and drawbacks of using these type of elements?



Rong Tian's picture

Why do we often use Jaumann rate instead of Truesdell rate?

In the attachment, we show that Truesdell rate can by simplified to Green-Naghdi rate by assuming F .=. R and can be further simplified to Jaumann rate by assuming W .=. R(.)R(T), where .=. means approximately equal

kashoo's picture

Load-displacement curves

I am trying to simualet Indentation Hardness Testing in ABAQUS and feeling like that there is some problem in my model.

Whenever I try to plot load-displacement curves it gives me bumps in the curve. Any idea, what should I do?

Should I reduce mesh size, I have done but then it gives me error with step size and so on.,

a littel help with composite analysis with ansys


i am completely new using ansys for composites. any suggestions regarding 'how to start' and 'what to refer' will be of great help for me.

please anyone help me out with this, i has to do 'fatigue analysis of composite laminate' as the part of my project work.

thanks in advance.


Temesgen Markos's picture

Is imechanica evolving into mechanics.craigslits?

Lately I am feeling like imechanica is becoming a craigslist for mechanics than a forum. Most recent blogs are simply ads that do not generate any discussion. Neither do questions from people get any reply, not any where near to what it used to be.

The last journal club had about five or so replies and the current one has no comment with two days to end.

Is it just me or does any body else feel the same too? I feel we have to think about how we can have a community here than just a repository of mechanics related stuff.  

MichelleLOyen's picture

Female Science Professor-- blog and book

Nature recently favorably reviewed a new self-published book, based on a blog , by a "female physical sciences professor" in the US.  While the overarching theme is clearly about being a female in a male-dominated world, the writings on the blog (and in the book) are in many places general and provide lots of good advice and anecdotes about acadmic life.  The

Book for beam theory

Choose a channel featured in the header of iMechanica: 

Can any one suggest me book for detailed study for Timoshanko And Euler Burnoulli Beam theory?

CONTACT set up in irregular surface.-analysis in Ansys

Hi all, i am the final semester student in.Struc Mecha.For my final
project i have to model combine sheet pile with  FEM. i used ansys for
set up the model. Combination of AZ,HZ n RZ profile were developed
sheet pile. In my modelling i applied frictional contact to define all
the connection between two parts. When i run my calculation, it does
not converged when body get  contact. I was applied spring and small
load step in set up.but still does not work too..if anybody have any

Ying Li's picture

How to prevent the trash ADs at iMechanica?

Recently, more and more trash ADs appear at imechanica. The users like "ORDER CIALIS ONLINE - US DRUGSTORE FDA" have added the ADs at the comments. Is there any good method for us to prevent such behavior at imechanica? As one of the moderator, may I have the right to directly give such users name to system operator to prevent these trash ADs?

Any comments are welcome.

Ying Li

Zhigang Suo's picture

Mechanics thrives whenever it participates in advancing a new technology

This morning I was looking at the book Mechatronic Reliability by Wei Yang.  The forword I wrote for the book brought back memories of days he and I spent in Santa Barbara and Princeton.  The text of the forword follows.

Finance and Mechanics


Recent events about the financial crisis and generally spread turmoils on Economics and Financial Environments  lead me to these conclusions.

Critical Speed:  informations, a key issue on finance, reached a critical speed. Maybe this is the "first" critical speed of the system. Speed of informations has reached the same order of magnitude of people's judgement (executives and investors more than others) so there's a sort of over-reaction about actual events.

Teng Li's picture

iMechanica: 9000 registered users, 30,000,000+ web hits

The number of registered users of iMechanica reached 9000 on 13 October 2008, after two years and one month since the website launch. The total number of posts is 4036, the total number of comments is 8888, and the total web hits is estimated to be more than 30,000,000.

Hosted at Harvard School of Engineering and Applied Science and maintained by a growing number of volunteers, iMechanica aims

The post LHC universe?

Most of you have heard about the commissioning of the Large Hadron Colider (LHC) by CERN and then the explosion of Helium followed by a postponement of operation until spring next year.  One of the worries some people had was that a mini black hole would be created by the collsions.  Also, the anthropic principle in one of its forms suggests that every possible universe exists but we see only our universe because it's the one in which intelligent observers exist.

How to ask a question on iMechanica

I've mostly had quite helpful responses from iMechanica participants whenever I've asked questions on this forum.  However, I've noticed that questions from several posters have gone unanswered.  I feel that there are two main reasons for that lack of response:

1) The questioner has not provided an adequate details by which they can be identified.  I generally don't like responding to a question posed by someone called xyz1983. 

Mike Ciavarella's picture

China: The prizes and pitfalls of progress

Remember when I spoke of the Easterlin paradox (a key concept in happiness economics postulated by Richard Easterlin in the 1974 paper "Does Economic Growth Improve the Human Lot? Some Empirical Evidence."[1]
It finds that, contrary to expectation, happiness at a national level

Mike Ciavarella's picture

Mars and Venus - How Europeans and Americans View and Use Science - ESOF July20th -Part 1: The Eu Perspective -

From ESOF, an interesting presentation, attached. 

Mars and Venus
How Europeans and Americans
View and Use Science<
Part 1: The European Perspective

Dr Roland Schenkel, Director General, European Commission, Joint Research Centre (JRC)

 Some quotes


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