iMechanica - In Quest of Virtual Tests for Structural Composites - Comments

Rui:Thanks. Guess I am still

Qingda Yang — Fri, 01 Dec 2006 13:47:25 -0500

Rui:
Thanks. Guess I am still playing catch up with these internet features. Yes, I wll try to at least give a DOI. Best, QDY

Cite the paper with no hyperlinks

Rui Huang — Fri, 01 Dec 2006 13:09:48 -0500

Qingda:

Is it a problem to list the citation info with no hyperlink or attachment?

You may also try item no. 5 in Zhgang's tip. Using the Digital Object Identifier (DOI), only those who have subscriptions to the jounral can access the full article.

Of course, if you prefer more personal contacts, just hide it well...

Zhigang, Thanks for the

Qingda Yang — Fri, 01 Dec 2006 12:32:23 -0500

Zhigang,
Thanks for the tips. Unfortunately for this particular article there is a relatively big difference between the final preprint and journal article. I would rather sending a perfect copy to those interested than attaching an imperfect one. Still,your tips are valuable for future papers. Thanks again.

Most journals allow authors to post PREPRINT on line

Zhigang Suo — Fri, 01 Dec 2006 07:29:55 -0500

Qingda: Most journals allow you to post the preprint prepared by yourself. You may check this web site for permissions of many journals.

You may also want to give the citation in your post, so that people can download the paper themselves from the web site of the journal, through their own institution.

See a related post on how to cite a journal article.

Please contact me for the article

Qingda Yang — Thu, 30 Nov 2006 22:09:19 -0500

Sorry I had to delete the attachment due to copyright concern. I will happy to email preprint upon contact/request. Sorry for the inconvenience. Qingda

Re: In quest of virtual tests

Qingda Yang — Thu, 30 Nov 2006 09:19:34 -0500

Suku,

Glad you are intersted in this article.

Your questions are right on. It would bevery costly if we track each of those microcracks although it will be nice if one can do so. That's why continuum damage mechanics based theory are still used. That's said, there are also some kind of major cracking systems that can be suitably dealt with cohesive zone model, which is basically what I have tried and they seem to work better than I expected. I am still in the early stage of tackling the secondary cracking systems -- I do have some tthoughts on avoiding use full 3D model, shall call you up and chat with you. Your help is definitely needed ....

Abaqus does have some preliminary feature for incorporating damage, using solution dependent field variable is one way to go, but it's abit awkward. But, one can always develop user-defined materials for such purposes and this is why I prefer it over other commercial package, so far ...

Qingda

Re: In Quest of Virtual Tests . .

N. Sukumar — Thu, 30 Nov 2006 01:58:57 -0500

Hi Qingda, Just read your article with interest, and found the review on the many issues of fracture/failure modeling that you've touched upon to be insightful and informative. A few questions (correct me if I am off-target). Is failure in composite laminates (0/90/..deg) and studying crack growth/delamination well-suited for continuum (fem/xfem-based) methods? You've discussed fiber bundles in the last page or two. It would appear that a combined continuum-discrete model would be better suited for fiber-matrix composites (for example, random distribution of fibers in a matrix)? Leaving aside the inherent complexities (debonding/apt cohesive laws between fiber/matrix, etc.), trying to track diffused damage in so many fiber-matrix interfaces would be a challenge and prohibitively costly in a 3D setting? Does ABAQUS provide capabilities for coupling continuum fem and structural elements or are there possibly better/other alternatives within the package?

In Quest of Virtual Tests for Structural Composites

Qingda Yang — Tue, 28 Nov 2006 14:16:19 -0500

Listed below is a recent publication of mine in Science for your possible interest and critics. This is a review article focusing on the multiscale simulation issues in strucutral composites. I will be more than happy to discuss with those of you who are interested. The following is the abstract.

The difficult challenge of simulating diffuse and complex fracture patterns in tough structural composites is at last beginning to yield to conceptual and computational advances in fracture modeling. Contributing successes include the refinement of cohesive models of fracture and the formulation of hybrid stress-strain and traction-displacement models that combine continuum (spatially averaged) and discrete damage representations in a single calculation. Emerging hierarchical formulations add the potential of tracing the damage mechanisms down through all scales to the atomic. As the models near the fidelity required for their use as virtual experiments, opportunities arise for reducing the number of costly tests needed to certify safety and extending the design space to include material configurations that are too complex to certify by purely empirical methods.

Link to the article:

http://www.sciencemag.org/cgi/content/full/314/5802/1102

Or, contact me directly for the PDF file. Thanks.