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LG's picture

Some questions about wave propagation

Dear Sir

As we know, periodic signals are best analysed in the frequency domain while stochastic signals are usually more profitably analysed in the time domain. The analysis in the frequency domain usually concern only one signal while in the time domain often involves the comparison of several different signals.

1) what are the general methods for transforming the frequency domain into time domain, and which should be superior?

Regarding LAMMPS

Is there anyone using LAMMPS for nano-mechanics? or for dislocation analysis?

I would like to discuss few things.

A Problem in Nature Of XFEM Approximation

There is a basic problem in NATURE of approximation of discontinuity in element using XFEM.I tried to illustrate that below:
for example, If you consider an element with strong discontinuity( like fracture or contact) which usually we use heaviside function as enrichment function. we expect two parts of element deform independently because of nature of problem.

In equation for approximation of this element we have two main parts. First  is 'regular' or 'standard' part which uses the standard shape functions of element and Second is the enriched part.

Dan Gianola's picture

Faculty Position in Materials Science and Engineering at the University of Pennsylvania

The Department of Materials Science and Engineering at the University
of Pennsylvania
invites applications for a tenure track faculty
position
. Applications will be considered from outstanding candidates
in any emerging area of Materials Science and Engineering. Successful
candidates will be committed to excellence in undergraduate and
graduate teaching, in particular curriculum development related to

Mechanics connection to memory

Mechanical tension contributes to clustering of neurotransmitter vesicles at presynaptic terminals. 

Scott SiechenShengyuan YangAkira Chiba and Taher Saif

The Meaning of the Concept of Potential in Mechanics (and in Physics)

If someone knows of books/articles dealing with the meaning of the concept of potential in physics (or concerning the physical bases underlying the energy methods of mechanics) then I would very much appreciate getting to know about these.

Wondering about the Mechanics of Bacterial Death

0. I was idly thinking about the current H1N1 flue pandemic, and the following things occurred to me. Please note, I know very little about this subject matter. So, please consider descriptions in the following as, at best, tentative.

1. There is a basic difference between how alcohol kills viruses and how salt-water kills bacteria. [Alcohol is used in the hand-cleaners they use in hospitals. Girgling with salt-water is the first line of defense (and an unexpectedly highly effective one) which is well known for millenia.]

But the mechanisms involved are different.

Fourth International Conference on Engineering Failure Analysis (ICEFA IV) - abstract deadline 27 November 2009

Following successful meetings in Lisbon, Toronto and Sitges, Elsevier will host the Fourth International Conference on Engineering Failure Analysis (www.icefa.elsevier.com) at Churchill College in Cambridge from the 4th - 7th July 2010. You are invited to participate in the latest in this important series of conferences, which have established a respected biennial forum for the discussion and dissemination of knowledge and experience in Engineering Failure Analysis.

8th International Conference on Fatigue Damage of Structural Materials - abstract deadline 7 December 2009

The eighth biennial Fatigue Damage of Structural Materials conference (www.fatiguedamage.elsevier.com) will once again be held in scenic Cape Cod at The Resort and Conference Center at Hyannis, Hyannis, Massachusetts from the 19 - 24 September 2010. Hyannis is situated on the historic Cape Cod peninsula just 90 minutes from either Logan International Airport (Boston, MA) or TF Green Airport (Providence, RI). 

Damage Investigation In Drilling of Polymer Matrix Composites

hii friends

              I am doing project on damage investigation  in drilling of polymer matrix composite and using FEM approach ABAQUS 6.8. so i want to damage compare between trepanning tool & twist drill. i have problem in simulation and  plotting(graph). so plz solved this problem

graduation project request


My name is Anis Turki, I am an engineering student at the Tunisia Polytechnic School.

Tunisia Polytechnic School (TPS) is the first high school of engineers in Tunisia. It provides a  multidisciplinary training for its students. Its main purpose is to enable them to assume both technical and administrative responsibilities.

Question in sequentially coupled thermal stress analysis using ABAQUS

I was wondering if anyone has solved a “sequentially coupled thermal stress analysis” problem using ABAQUS?

If so, here is what I am looking to solve.

Let’s assume we solved for the temperature (T) as a function of time and space using the transient heat transfer analysis given certain BCs.

Mechanical Engineer

LightSail Energy, Inc. is an exciting, well-funded startup in the
$100 billion field of green tech energy storage.  We are located
in the San Francisco Bay Area.  We are seeking to fill several
Mechanical Engineering positions.  Applicants should have at least
5 years experience in product design of mechanical components.
Please be familiar with at least some of the following:
design of hydraulic and pneumatic systems, heat transfer,
thermodynamics, fluid power, pistons and seals, and multiphase

Clarifications o Stroh formalism

sir,

I am solving some problomes for Stresses around holes for Anisotropic cases. In this connection most of authors have solved the stresses in cartesian co-ordinates only. Can I have any papers which are solved in polar co-ordinates by Stroh formalism for Stresses around holes in Composite laminates.So kindly help me

thanking you

 M.Ramesh Babu 

Rui Huang's picture

von Karman plate equations

Many of us (including myself) have used the nonlinear equations for elastic plates, originally proposed by von Karman (1910). I recently came across a book with some interesting comments about the plate equations, which may be of interest to share with others on imechanica. The book's title is "Plates and Junctions in Elastic Multi-Structures", authored by Philippe G. Ciarlet and published by Springer-Verlag in 1990.

Phd Position at Ecole des Mines de Douai (FRANCE)

One PhD position on NDT for 3 years at Ecole des Mines de Douai (FRANCE).

329878819@qq.com's picture

Looking for a postdoctoral position in materials science and engineering

Dear all

I am looking for a postdoctoral postion/research fellow in materials science and engineering. My background and skills in lab techniques will prove to be an effective match for your qualification.

I have a master' degree in materials science and engineering and will get my PhD degree of materials science and engineering at the end of 2010' spring. I have been focused on the field of TiAl-based alloy, with particular attention on smeling and casting, phase transformation, numerical simulation of flow field using ANSYS for four years.

how to start a research

hi all,

 I am a mechanical engineer currently pursuing Master degree (Post graduation). Ultimately i also want to pursue a research leading to PhD after my master's. Its my burning desire to do some significant research in the field of Fatigue analysis using Fracture mechanics approach preferably for aerospace domain using advanced CAE softwares like Nasgrow, Afgrow, Abaqus, FE-safe, MSC Fatigue, etc,..

zishun liu's picture

International Journal of Applied Mechanics (IJAM) Vol.1 No.4

Forthcoming papers of International Journal of Applied Mechanics (IJAM) Vol.1 No.4 

1. “Strain Deconcentration In Thin Films Patterned With Circular Holes”, Matthew B. Tucker and Teng Li, (University of Maryland, USA). 

I'm looking for a new vibration exciter

I'm looking for a new vibration exciter which exciting frequency can reach 300hz .I'll use it to load the cantilever beam specimen , compare the  fatigue life of the specimen under different loading frequency. the electric exciter can not  generate the same amplitude under difference exciting frequency.

who can tell me that how can I found or design a mechine to finish the expriment.thank you

vh's picture

Compositional patterning in coherent and dislocated alloy nanocrystals

Variations in the distribution of the alloy components can significantly influence the electronic properties

of self-organized alloy nanocrystals. Using a combination of finite element and quadratic programming

optimization methods, we have developed an efficient numerical technique to compute the equilibrium

composition profiles in coherent and dislocated nanocrystals. We show that the variations in composition

profiles arise due to the competition between chemical mixing effects and the relaxation of composition-

dependent mismatch strain as well as strain due to dislocations. We find that the composition profiles

How to attach a file to a comment?

Drupal, the software that powers iMechanica, treats comments very differently from a blog entry.  You cannot attach a file to a comment directly. 

One way to link to a file in the comment is to first write a new blog entry, where you can upload the file. The blog entry and the uploaded file have distinct URLs. In your comment, you can choose to hyperlink to your blog entry, or to the uploaded file.

Abaqus error help for radiation

I am runnin simulations for heat transfer analysis counting conduction, when I add the effect of surface radiation to environment with *radiate or *sradiate , I am getting the error message:

***WARNING: Temperature at 1 nodes has fallen below absolute zero. Increment
             will be attempted again with a new time increment. The nodes have
             been identified in node set WarnNodeTempBelowZeroStep2Inc45.

               CONVERGENCE CHECKS FOR EQUILIBRIUM ITERATION     1

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