iMechanica - Comments

Hi Graham, Thanks for ur

Gurudutt Chandrashekar — Sat, 31 Jul 2010 09:41:20 -0400

Hi Graham,

Thanks for ur suggestion. I have made all my subroutines in F90 . I got a doubt when i read in one of the abaqus documents on "Writing User Subrotines in Abaqus" that we have to specifically use F77 conventions. I should now figure out a way of configuring my Abaqus to use my F90 subroutines.

Hi Wei, Thanks a lot

Gurudutt Chandrashekar — Sat, 31 Jul 2010 09:16:48 -0400

Hi Wei,

Thanks a lot for ur reply..I think that cleared all my doubts about compiler compatibility..

Good contents, i think i

Andrea Sansonetti — Sat, 31 Jul 2010 05:32:25 -0400

Good contents, i think i will buy it.

Temperature dependent elastic properties

Thomas A. Mason — Sat, 31 Jul 2010 01:02:04 -0400

You might also look at the data present in "Single Crystal Elastic Constants and Calculated Aggregate Properties. A Handbook" by Gene Simmons and Herbert Wang, MIT Press, 1971. You can fit your favorite curve to the data collected there.

It only depends on your compiler

Wei Hong — Sat, 31 Jul 2010 00:47:08 -0400

Hi Gurudutt,

The compatibility in the format of the fortran source code is on the compiler side, not on Abaqus. As long as your compiler works with f90 or f95, your user subroutines can be linked with Abaqus. For most compilers, e.g. Intel Visual Fortran, f90 and f95 are supported as well as f77.

Wei

Dear Adrien

dubuking — Sat, 31 Jul 2010 00:46:13 -0400

HI~. I think your question has been ansered by Kyle. In the explicit code, the time increment is determine by the elemene size and the density of the model material, the time increment decreases as you use finer meshes. Thus, you should check the denominator in the subroutines.

regards,

Sangyul Ha

Have you tried yet?

Mike Graham — Fri, 30 Jul 2010 18:51:57 -0400

I have never done this, but I don't think there should be a problem in general. Make sure you've configured Abaqus to use a Fortran 90-aware compiler and if you're lucky it will Just Work.

I have used Abaqus user subroutines written in C++. In that case I just provide Abaqus the object file instead of the source code and it links it without caring what generated it. When you provide user=something, Abaqus automatically checks to see if it's source code or precompiled.

Writing subroutines in Fortran90 or higher versions

Gurudutt Chandrashekar — Fri, 30 Jul 2010 16:25:43 -0400

Hello everyone,

I am a student of Msc in Computational Engineering at Ruhr University Bochum in Germany. I am implementing a new piezoelectric element as a part of my Master Thesis. I am supposed to write a UEL subroutine and implement it in abaqus.I would like to know whether anyone has written subroutines in Fortran 90 or further versions and implemented them in abaqus. All the Help documents in Abaqus have subroutines written in F77. If it possible in F90, then it will be very helpful if someone could point out the necessary modifications that one has to make to the F90 file to run it in Abaqus. I think many ppl have this question .I myself have been trying to figure out an answer from past 1 month but could not find a convincing solution anywhere.

Dear Thanasis, Thanks for

mremami — Fri, 30 Jul 2010 15:54:29 -0400

Dear Thanasis,

Thanks for the comment. Actually, I want to model the adhesion of a coating to the Aluminum substrate using ABAQUS. I read all the help of ABAQUS to understand this type of modeling. Now, I know that I have to model it by COHESIVE ELEMENT and using "traction-separation constitutive response". The problem is that I need an example of this kind of modeling to find out the modeling procedure.

Would you please send me the procedure of modeling (step by step) during an example?

Thank you in advance.

The Handbook of Aluminum,

e_garcia — Fri, 30 Jul 2010 11:46:29 -0400

The Handbook of Aluminum, Vol1. Physical Metallurgy and processes, edited by George E. Totten and D. Scott MacKenzie.

e_garcia

While ASM Handbook is the

Hardik.M.Singh — Fri, 30 Jul 2010 11:43:18 -0400

While ASM Handbook is the acceptable standard, you can also look at www.matweb.com for quick refernce . You will get all the properties of metal that you have mentioned. Most of the researchers in the simulation world use this website.

-Hardik

Hi,Bashir,Thanks for

zhangxiaodong — Fri, 30 Jul 2010 10:21:26 -0400

Hi,Bashir,

Thanks for your attention.

When I say we intend to solve a equation of the form K(u)u =f , I refer to the discretized incremental form of the equation f_int(u) = f_ext. In nonlinear dynamic analysis, the equation system is supposed to be like

Kt(du)du=R

where kt(du) is tangent matrix. My trouble is how to get this tangent matrix.

I did derived some formulations, but the corresponding code does't work well. And I don't know the reason.

The formulations can be found in the attached file. Any advice will be appreciated.

Difficulties when adding image

Peter Cendula — Fri, 30 Jul 2010 10:16:16 -0400

I tried to add an image to my comment, so I uploaded it first with 'Add image' link in separate window and then dragged it to the original window with my comment.

The preview image appears in the comment and I set it up to be a "link to image page". However, when I preview the comment, the image is a link but points to a page like "http://imechanica.org/img_assist/properties/8626", which is the edit page of the image ;-(

The other feature which is not working - "Insert" button does not insert the image anywhere.

We should improve adding images more user-friendly, I'll be glad to help the web administrators.

Thanks

Peter

Re: Stiffness of NPR materials

Lifeng Wang — Fri, 30 Jul 2010 09:30:52 -0400

Dear Matt, Roberto, and Katia,

I think in certain negative Poisson ratio materials, the stiffness could be high, such as in nacre (ref 18, Phys. Rev. Lett., 245502, 2008). Recently I have a study on a structural composite material inspired by the inner nacreous layer of seashells. We demonstrate this hierarchical mineral/polymer microstructure can be tailored to achieve not only stiffness and strength, but also lateral plastic expansion during tension (a negative “plastic” Poisson’s ratio) providing a volumetric energy dissipation mechanism. However, unlike many other examples of auxetic materials the negative plastic Poisson’s ratio is rarer and has a significant effect in promoting the plastic deformation capability and toughness of the composite.

This paper is available from http://dx.doi.org/10.1002/adfm.201000282

Bioinspired Structural Material Exhibiting Post-Yield Lateral Expansion and Volumetric Energy Dissipation During Tension, by Lifeng Wang and Mary C. Boyce, Adv. Funct. Mater. 2010.

Lifeng

Thanks for your help

aelias — Fri, 30 Jul 2010 04:52:40 -0400

Thanks for your help Kyle.

I thought about that however the error occurs even when I use a coarse mesh (as long as the mesh density is variable). A regular mesh, even with very small elements, doesn't induce this error. But I will check again the subroutine. Do you have any other idea about what could cause this error?

Thank you

Adrien