iMechanica - Blog entry - Comments

Very Interesting

Nicholas Cafarelli — Wed, 07 Jan 2009 14:43:52 -0500

I have been pondering how to use a laser optical mouse for sub-revolution torque measurement.

Fortunately I found your blog.

Can you share more of your approach please?

Thank You Shengke Zhi.

Re: volumetric decomposition of anisotropic materials

Sugeng Waluyo — Wed, 07 Jan 2009 02:41:27 -0500

Dear Zaoyang,

I read your paper in http://www.mech.gla.ac.uk/~zguo/Publications/J014.pdf briefly. I am wondering in which situations a "pure" hydrostatic compression are exist in practice, thus your mathematical argument can be meaningful.

Thanks a lot for the answers.

Best regards,

Sugeng

Congratulations

Yanfei Gao — Tue, 06 Jan 2009 12:13:43 -0500

I second Roy's comment. That will come soon.

After i saw andrew zimmer on

jasonla — Tue, 06 Jan 2009 11:37:37 -0500

After i saw andrew zimmer on travel chanel go to beijing and other ares near there i wanted to make a trip there so i found royal caribbean went to a few cities and took a trip. I went to the same places he did and tried the same foods i had such an amazing time there that i am planning to fly back this year.

Ls Dyna

bharath — Tue, 06 Jan 2009 02:18:45 -0500

BHARATH. P

Hi

sunangel46 — Mon, 05 Jan 2009 23:19:30 -0500

I am working on the exactly same example using ANSYS ls-dyna, do u have a similar tutorial on that? As I am just a newbie on that and even don't know how to get started.

I would really very appreciate if you can provide a link or anything that helps.

Thank you very much.

hi civilmh, i have

suren — Mon, 05 Jan 2009 01:46:52 -0500

hi civilmh,

i have an idea to start an indentation with a conical tip on a thin film , can u pls suggest me how to start this in ANSYS. thanks for your attention.

Information regarding the Phd position in multiscale modelling

romeoalonetoo — Sun, 04 Jan 2009 11:17:11 -0500

Dear Sir,

I Shaik Mohammad Ashraf Ansari has studied master's in Computational Enineering at University of Rostock,Germany. I Would like to know the information regarding the phd position in yous department. is this position still available? if so then what are the documents needed and required to submit to apply for the phd position.

Thanking you,

your's faithfully

Ashraf

Very cool design! I find

qectory — Sun, 04 Jan 2009 06:00:56 -0500

Very cool design! I find very interesting information at this article, thanks.

You are probably right,

mixmagtmb — Sat, 03 Jan 2009 14:31:22 -0500

You are probably right, though now such period many work with new projects in a consequence of it not so a lot of time allocate to their discussion.

good

ferary — Sat, 03 Jan 2009 07:08:33 -0500

I have been looking for sites like this for a long time. Thank you!

Me too

Olumide — Sat, 03 Jan 2009 03:38:45 -0500

Hello,

'new to imechanica .. I'm trying to solve a similar problem. I would like to model the behaviour of curved muscle fibres, and I'm at a loss as to how to go about solving the problem, considering that the muscle fibres are separate entities, yet act as a single bundle.

- Olumide

Stress jump in compression of single crystals

Caizhi Zhou — Fri, 02 Jan 2009 17:04:09 -0500

Experimental micro-compression studies showed the staircase stress–strain behavior. However this behavior is not obvious in larger samples and the polycrystals. ‘Dislocation starvation’ mechanism often used to describe this behavior. However, in-situ TEM experiment just could verify this mechanism in small samples with diameter smaller then 200nm (Z.W. Shan on Nature Mater., 2008). In larger samples, dislocations could not be fully eliminated. And the measured flow stresses of micropillars are much lower than those of nanowires. That means the plastic deformation of micropillars not nucleation controlled.Currently, there are several explanations on staircase stress–strain behavior as following:One is that the moving dislocations was trapped by the junction and caused the intermittency of plastic deformation (S.I. Rao on Acta Mater., 2008). So the applied stress must be increased to sustain the applied strain rate. Actually, how often of the moving dislocations could be trapped by the junctions and whether the junctions are strong enough to cause such high stress jump in the stress–strain curves are two major questions on this explanation.The second explanation is the cross-slip of the moving dislocations divided them into several shorter segments, and then the stress need to be increased to bow out the shorter dislocation segment (J.A. El-Awad on JMPS, 2008). But this explanation could not be verified by atomistic simulation at this time. The above two explanations are both based on 3D dislocation dynamics simulation.The third explanation based on FEM simulation is that the rotation of sample after yielding could change the Schmid factor on slip planes and then cause the change of flow stress (Y.S. Choi on Scripta Mater, 2007). Actually, the rotated sample under bending may also trap moving dislocations at the neutral plane where there isn’t share stress and the applied stress need to be increased to bow out new dislocations. In addition, even the rotation of sample is not obvious, there must be some surface steps caused by the slip out of upper part of the sample. This surface steps decreased the original area of the slip planes on which active dislocations are moving, and then shortened the effective length of dislocation arms. This also might case the increase of applied stress. However, the underlying mechanisms are still under debate. More sophisticated modeling and simulations are still needed to determine which conjecture would take the dominate role on the stress jump in compression of single crystals.

I've earned a few degrees

jasonla — Fri, 02 Jan 2009 15:15:24 -0500

I've earned a few degrees online through the university of phoenix having access to other universities by video seeing their classes would be great.

ABAQUS SMA models

churchc — Fri, 02 Jan 2009 15:11:06 -0500

I know that Prof. Lagoudas at Texas A&M has several 3D sma models, so maybe you could contact one of his grad students for some help, or at least read his modeling papers. I myself am working on my own uel and umat for a 1D SMA, but am only in the beginning stages. Our group has 1D elements in 2 other FEA packages, so my first task is the non-trivial porting of code.