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Updated: 1 hour 41 min ago

This position has been filled

4 hours 42 min ago

In reply to Postdoc position at University of Glasgow

This position has been filled

Great initiative!

Mon, 2020-11-23 08:36

In reply to CSME Congress 2021 - Symposium on Solid Mechanics

Dear Hamid,
Great initiative! I'm looking forward to this. Hopefully, we will be allowed to travel to PEI.

Thanks for sharing

Fri, 2020-11-20 11:56

In reply to D. Rittel - DYMAT webinar

I read some of your work.

Re: Cloaking in plates

Tue, 2020-11-17 18:14

In reply to Transformation Cloaking in Elastic Plates

Dear Michele:

Thank you for your message. I was not aware of your PML paper and just read it. In Eq. (17) of your PML paper the transformed elastic constants are correct. You cited your older papers but I wonder why the discrepancy between the two transformed elastic constants was not discussed? The continuity conditions on the PML boundary (your Eq. (30)) are correct. However, this will not make your cloaking formulation in your previous papers work. There are still some constraints (coming from matching the different terms in the governing equations of the virtual and physical plates) that will ultimately force the cloaking map (or your "transformation" map) to be the identity. Exact cloaking is not possible. I am not claiming that approximate cloaking is not possible. However, it should be formulated properly as an optimization problem. 

Regards,

Arash

Cloaking in plates

Sun, 2020-11-15 13:54

In reply to Transformation Cloaking in Elastic Plates

Dear Arash Yavari,

thank you for your interesting work.
Concerning your criticisms on our work concerning your eqs. (1.1) and (1.2), they were already solved in the paper I published in (2018), i.e. https://www.sciencedirect.com/science/article/pii/S0020768317305140?via%3Dihub

Transformed equations and interface/boundary conditions have been reported in Section 4.

In Section 5, we propose the eigenfrequency analysis as a tool in order to check the transformation.

There, higher order polynomials were implemented in order to respect interface conditions between untransformed and transformed domains.

 

Anyway, concerning the formulation reported in 
1) D. J. Colquitt, M. Brun, M. Gei, A. B. Movchan, N. V. Movchan, and I. S. Jones. Transformation elastodynamics and cloaking for flexural waves. Journal of the Mechanics and Physics of Solids, 72:131–143, 2014. 

2) M. Brun, D. Colquitt, I. Jones, A. Movchan, and N. Movchan. Transformation cloaking and radial approximations for flexural waves in elastic plates. New Journal of Physics, 16(9):093020, 2014.

and 

3) I. Jones, M. Brun, N. Movchan, and A. Movchan. Singular perturbations and cloaking illusions for elastic waves in membranes and kirchhoff plates. International Journal of Solids and Structures, 69:498–506, 2015.

the comparison between untransformed and transformed domain show an excellent agreement apart from the neighbourhood of the interface between untransformed and transformed domains. The difference between solutions in the reference and transformed domains was considered quantitatively in (1) through the scattering measure.
Anyway, the difference is small.

May you guess why?

 

Best,

Michele Brun 

Great event

Mon, 2020-11-09 17:04

In reply to Event of ASME Technical Committee on Mechanics of Soft Materials 2020

Thank you for sharing. Great event with great speakers!

pull-through test

Mon, 2020-11-09 13:53

In reply to VUMAT viscoelasticity (Maxwell model)

Hello Surot

just give it a try and see if the result matches your data.

How is this pull-through achieved ? By suction induced by vacuum ? You might check the literature on thermoforming, a process where a disk is heated and then makes contact with a mold.

I advise you to subscribe to and seek assistance from the ABAQUS mailing list
https://groups.yahoo.com/neo/groups/Abaqus/info
Search the archive of the list before posting in it.
The list does not accept attachments.

If you have a UMAT for generalized Maxwell implementation, you might also look at this interface:
https://soilmodels.com/download/vumat_umatinterface-zip/
No comment from me on that; I never worked with it.

If that Kelvin-Voigt VUMAT somewhere available on the Internet ? Just curious, I was also searching for that a few years ago.

Good luck,

Frank

Mineral processing

Mon, 2020-11-09 10:19

In reply to Faculty positions at Northeastern University in China

Mineral processing

Tribology, Mechanics,

Fri, 2020-11-06 06:49

In reply to Postdoc in Mechanics/Tribology and/or Triboelectric Nanogenerators

Tribology, Mechanics, Triboelectric

Thanks, Emilio, we are

Fri, 2020-11-06 02:55

In reply to Great opportunity in a great

Thanks, Emilio, we are flattered!

Great opportunity in a great

Fri, 2020-11-06 01:11

In reply to Two postdoc positions in computational mechanics at Czech Technical University in Prague

Great opportunity in a great environment. I couldn't recommend more!

Thank you Cheikh for the

Thu, 2020-11-05 09:28

In reply to Phase field modelling of fracture and fatigue in Shape Memory Alloys

Thank you Cheikh for the clarification. In my view, the phase field method is a mathematical model, not pertaining to any scale. It is of course widely used in microstrutural evolution, as you say. But it is also very widely used in other interfacial problems at many differente scales. Fracture is one of them, where the phase field order parameter is used to differenciate between the cracked and solid parts of the material. Hope that this clarifies things.

Thank you Emilio for the

Thu, 2020-11-05 08:46

In reply to Phase field modelling of fracture and fatigue in Shape Memory Alloys

Thank you Emilio for the answer. When I saw phase-field modeling which is known as a microscale method, I expected more details about the microstructure evolution such as the competition between the different martensite variants instead an averaged martensite at the macroscale.

Regards,

Cheikh 

Unfortunately, the #EURAXESS

Thu, 2020-11-05 05:56

In reply to Two postdoc positions in computational mechanics at Czech Technical University in Prague

Unfortunately, the #EURAXESS link was inactive, but it is working again. Apologies for any inconvenience caused.

Comment

Tue, 2020-11-03 12:39

In reply to PhD opportunity within the ITN NreFrac Computational Fracture Mechanics

Please feel free to ask any doubt about the offer

Dear Cheikh,

Mon, 2020-11-02 12:09

In reply to Phase field modelling of fracture and fatigue in Shape Memory Alloys

Dear Cheikh,

Thanks for your interest. The phase field method is used to model the cracking. It is a phase field fracture method. The martensite-austenite transformation is taken care of using averaged internal variables, as you say. One could use a two-field phase field approach but this is not the purpose of our work. Our aim was to present the first phase field formulation for fracture (and fatigue) in SMAs.

Best,
Emilio Martínez Pañeda

Nice work, but it looks more

Mon, 2020-11-02 10:10

In reply to Phase field modelling of fracture and fatigue in Shape Memory Alloys

Nice work, but it looks more phenomenological with averaged internal variables than PFM with order parameters. 

Thanking Prof. P. Sharma

Sun, 2020-11-01 13:45

In reply to New results on shock mitigation of MC gels to appear in JMPS

the authors thank prof. P. Sharma, the JMPS editor who handled our paper with utmost efficiency and courtesy

Since we are in the business

Fri, 2020-10-30 14:30

In reply to Dear Zhigang,

Since we are in the business of advertising codes, let me also pitch in mef90/vDef, the open source parallel implementation that I have used for almost all of my work in the field in the last 25 years or so.

Blaise

More references

Fri, 2020-10-30 13:52

In reply to Dear Per,

Dear Per, Emilio, and others,

The 2001 paper is a bit dated now. Our 2008 long article / book "The variational approach to fracture" (DOI: 10.1007/s10659-007-9107-3), although also dated by today's standard, provides a good view of the foundations and theory of a field that is about 25 years old, even though many have discovered it recently.

 

Blaise

 

 

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