iMechanica - suo group research - Comments

RCC BEAM MODEL

suman.subhajit — Sun, 14 Jun 2009 16:45:58 -0400

I want to model a RCC beam using ABAQUS software. plesae help me....

subhajit mondal

growthflex

growthflux — Wed, 03 Jun 2009 04:21:08 -0400

hai sir i have interested in pursuing PhD in fracture mechaincs and FGM area. Shall I apply for the PhD opening which was called up recently in your blog.

Re: PhD study of Solid Mechanics at Harvard

Zhigang Suo — Sat, 18 Apr 2009 17:58:32 -0400

Here is a description of PhD study of Solid Mechanics at Harvard University.

PhD

nggovind — Thu, 16 Apr 2009 06:18:40 -0400

Dear Prof Suo.

I am pretty much interested in pursuing PhD in fracture mechaincs and FGM area. I ve 6 years of industrial experience. Shall I apply for the PhD opening which was called up recently in your blog. what is the pre-requeste?

regards

Govind.

Dear Nanshu, I see that

maherelabd — Thu, 19 Mar 2009 09:35:29 -0400

Dear Nanshu,

I see that you have a very good experience with ABAQUS. I hope you can help me with the following very simple problem.

I have a problem simulating earthquake effect on a very simple structure. The structure is a 2 story steel plan frame structure. with lumped mass at its corners.

I am applying the Northbridge earthquake on it but I am getting very strange results.

I am applying the Material density beside the lumped mass at corners. I do not know if using lumped masses is correct like this or not.

Both, eignvalues and frequencies and also responses are not correct.

I attached the input file and also the acceleration time history for the earthquake.

The input file extension was changed to txt so the server can accept it.

Here is the link

http://imechanica.org/node/5090

Looking forward to hearing from you.

Regards for all,

Maher Elabd

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.

Thank you for your site. I

gerardino — Sat, 27 Dec 2008 05:44:52 -0500

Thank you for your site. I have found here much useful information...

hi wei, sorry that i did not

Chunguang Xia — Wed, 15 Oct 2008 00:37:40 -0400

hi wei, sorry that i did not follow up with this post. too late to see the post.

Hua, thanks for your comments

Hanqing Jiang — Wed, 15 Oct 2008 00:23:27 -0400

For your question 1, the driving force for mass transport is the gradient of chemical potential. Meanwhile, the chemical potential also depends on mechanical deformation. Therefore, for concurrent deformation and mass transport, as stated in the manuscript, "
disequilibrium", explicitly, disequilibrium of mechanical field and chemical potential, drives the mass transport.

We will make it clear for your question 2 when we revise the manuscript. Thanks.

Hi, Hanqing, Very nice to see you again.

Hua Li — Mon, 13 Oct 2008 08:05:00 -0400

Very nice to see you again. Thanks for Zhigang's email to let me know the latest output. It is really exciting work, and also challenges me to gain an insight
into. I am still on the surface and will learn from you.

1Q:
you said that "the solvent molecules, however, interact among themselves
and with the network by weak physical bonds, and enable the gel to be a conduit
of mass transport" (see in Abstract), and also that "Elements of the
gel in different locations may not be in equilibrium with each other, and this
disequilibrium motivates the solvent to migrate" (see Page 6)”. As
such, I didn't get your point – what is a driving source for mass
transport? Is it possible to give more detailed info.

2
minor suggestions: (1) you use "Nk(X)" representing the
unit vector normal to the element of area, and "Na(X)" the shape
functions, which may confuse some readers due to the quite similar symbols. (2)
It could be much better to add the reference citations for the parameter values
(in Page 10) you use as input data, and then we can follow up.

Thank you for your effort,

Hua

Hi Chunguang, I will be

Wei Hong — Fri, 10 Oct 2008 09:57:26 -0400

Hi Chunguang,

I will be in Champaign next week, too. Let three of us find a time to meet.

Tuesday during lunch time or in the evening will be good for me.

Wei

Hi Wei, I quite agree with

Chunguang Xia — Thu, 09 Oct 2008 22:52:00 -0400

Hi Wei, I quite agree with you on the current theories on hydrogel. And I am desperately looking a field theory that can explain our experiments. And that is why I am excited about yours and hanqing's work. I am very happy to see if your theory can explain and predict my experiments.

thanks

chunguang

let us meet

Chunguang Xia — Thu, 09 Oct 2008 22:51:39 -0400

Hi Hanqing, i am not good at thermodynamics and thank you and wei for helping me out the confusion. I am free all the next Tuesday. Let me know your plan.

thanks

Chunguang

Solvent concentration and deformation

Wei Hong — Thu, 09 Oct 2008 20:48:34 -0400

Hi Chunguang,
There are two things I might need to comment a little bit more:

Our theory does not need 1+aC=det(F) at the first place. The condition is just a simplification based on the incompressibility of the material. For incompressilbe material, even when it is dry, C=0, det(F)=0 should be satisfied. So there is no problem at all applying the theory to dry network.
At the current stage of research on hydrogels, I don't think there is any theory that could "predict" the behavior of a gel. It is more or less a curve fitting or extracting of material constants from observations. The theory presented in our recent paper is rather a theoretical framework than a material model. It would not predict anything without experimental input. In terms of material model, we merely adopted Flory-Huggins theory for the static behavior, and linear kinetic law for time-dependent behavior, as an example in that paper. If fitting a single curve is regarded as prediction, then all existing theories could "predict" equally well.

Hope these comments will resolve your concern. Wei

thanks for the comment

Hanqing Jiang — Thu, 09 Oct 2008 18:11:57 -0400

Dear Chunguang:

Thanks. Firstly of all, unlike biphasic theory or coupled solid/fluid mixture theory, Prof. Suo's theory does not have "dray area". The deforamtion gradient F is for the mixture (i.e. gel). If a dry gel, which has no solvent molecules or C =0, is taken as the reference configuration, det(F) will be zero. Also, I thank you for pointing our the time scale issue. The framework proposed by Prof. Suo does not depend on material model, namely free energy function and mobility tensor. To more accurately predict the time scale, a more accurate material model is needed.

PS. By the way, I will be at UIUC next Tuesday. Maybe we can meet

Thanks.

Hanqing