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skumaar's picture

Multiple PhD/Postdoc Positions/Spring 2015

Advanced Materials and Multifunctional Structures (AMMS) Group at Masdar Institute (MI) is seeking suitably qualified candidates for PhD/Postdoctoral positions. Please see attached document for details

Extinct Kangaroos Couldn't Hop

Another couple of interesting articles to share. Using some "mechanics" principles, researchers have reasoned that 100,000 years ago, kangaroos were too heavy to hop.

A while ago, a different group of researchers published the results of computer modelling (using genetic algorithms) that showed dinosaurs might have hopped and skipped as forms of locomotion! (But only if particularly happy?)

These articles might be good to share with undergraduate engineers for discussion in tutorials. There are issues to discuss with assumptions in both cases. 

Conversion of nanoindentation data into stress-strain curves

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Hello, colleagues! 

Could anybody help me with the problem? How to convert nanoindentation data (force - penetration depth) into stress-strain curves? Is there any method that allows to make such a conversion if Berkovich indenter was used?

 

Thank You!

 

Best regards, 

Loginov Pavel (NUST MISIS engineer)

Amit Pandey's picture

in-situ Young's moduli of the constitutive layers in a multilayer systems (e.g. thin films, SOFCs, TBCs etc.)

 

This recent article present an improved methodology to calculate in-situ Young's moduli of the constitutive layers in a multilayer systems (e.g. thin films, SOFCs, TBCs etc.)

Pandey, A., Shyam, A., Liu, Z., & Goettler, R. (2014). In-situ Young’s Moduli of the Constitutive Layers in a Solid Oxide Fuel Cell. Journal of Power Sources.

 

http://www.sciencedirect.com/science/article/pii/S0378775314015341 

 

Highlights

Amit Pandey's picture

in-situ Young's moduli of the constitutive layers in a multilayer systems (e.g. thin films, SOFCs, TBCs etc.)

 

This recent article presents an improved methodology to calculate in-situ Young's moduli of the constitutive layers in a multilayer systems (e.g. thin films, SOFCs, TBCs etc.)

 

Amit Pandey, Amit Shyam, Zhien Liu, Richard Goettler, In-situ Young's moduli of the constitutive layers in a solid oxide fuel cell, Journal of Power Sources, Volume 273, 1 January 2015, Pages 522-529

 

http://www.sciencedirect.com/science/article/pii/S0378775314015341 

 

Highlights

Experiment.com: Can molecules make music?

Experiment.com is a crowdfunding site for research (a Kickstarter for science!).

Open to all, a target amount for a project is set, and funds are raised through small individual donations. The success is based on how many people like your idea. It's kind of a fun/alternative idea to traditional grant sources! If you have an interesting idea, I recommend it.

kashif355's picture

Discrete and smeared approach

I am structural engineering student , working on discrete and smeared model of 1/4 th scale bridge girder using ANSYS software and facing some problems.Some problems regarding discrete approach are: 1. can I use beam188 instead of link180 for modeling reinforcing steel???2. what should I use value of shear transfer coefficient for open and closed crack ?? what is criteria for using these coefficient??3. How can I apply load in multi-steps (load step1 ,load step2 ,load step3. etc) ???4. How can I set convergence criteria???

Measurements of surface stress evolution

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Dear Colleagues,

We recently have reported first measurements of surface stress evolution in a material as a function of uniaxial time dependent deformation and at temperatures upto 100 degree C using a new analytical technology, Nanomechanical Raman Spectroscopy developed in our lab (Interfacial Multiphysics Lab directed by Dr. Vikas Tomar at Purdue).

Measurements of surface stress evolution

Dear Colleagues,

We recently have reported first measurements of surface stress evolution in a material as a function of uniaxial time dependent deformation and at temperatures upto 100 degree C using a new analytical technology, Nanomechanical Raman Spectroscopy developed in our lab (Interfacial Multiphysics Lab directed by Dr. Vikas Tomar at Purdue).

Obtaining Contact Results in ABAQUS Subroutine

I just found a utility routine in ABAQUS (GETVRMAVGATNODE) functioned to obtain contact information (e.g. contact pressure) detailed as follows:

Phase Field Simulation of Precipitation in a Binary Alloy

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Hello Everybody,

 

siamaktg's picture

Increase accuracy in calculating of strain energy in composite model (Abaqus)

<p>Hello guys</p>
<p>I want to increase my accuracy in calculating strain energy for whol model in a simple composite under static load.</p>
<p>please suggest some methods for increasing my accuracy to achieve a dramatically result.</p>
<p>If someone know about this issue please leave your email for sending my file .</p>
<p>Unlucky my file has a giant size and I cant upload it in this part.</p>
<p>please help me</p>

Questions about stresses distribution in pin-loaded orthotropic plates

Dear all,

I am now reading a paper about the stress distribution in pin-loaded orthotropic plates.

The paper 'Contact stresses in pin-loaded orthotropic plates' is written by Prof. M.W. Hyer.

In this paper, the stresses on the boundary of the hole in the plate are given by a complex Fourier series with unknown coefficietns Ak. The unknown coefficients Ak's are determined by a system of algebraic equations: [C]*{A}={B}. A collocation procedure is needed to construct the square matrix [C].

Transversely Isotropic Viscoelastic Material

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I am looking for a viscoelastic model for transversely isotropic materials with applications in geomechanics. I also look for the material properties and viscoelastic coefficients for one or two TIV material. Can any one help me? 

micro mechanic modeling of RVE in abaqus

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Hello All,

 

Abaqus Standard/CFD

Hi, I'm trying to solve a problem with heat transfer and fluid. When I co-execute heat transfer model and CFD model, the following error is encountered "An unrecoverable error has been encountered with the co-simulation engine".

Can anyone help me solving this error?

Gratefull for your attention.

Cracks found at reactor at Hunterston B nuclear power station

Perhaps some of those on this site have seen the news article on the BBC website yesterday about cracks appearing in the reactor at the Hunterston B nuclear power station. As the article states, cracking in the graphite bricks is predicted and the regulators are happy that the reactor is safe to operate.

Problem relating to Contact Pressure in ABAQUS Subroutine

I have already obtained the contact pressure (CPRESS) in the ABAQUS model.

NOW, I want to introduce a subroutine in ABAQUS which enables setting the contact pressure as input information, since contact pressue is the intial condition for another model which will incorporate with the existing model. I wonder if anyone can provide some suggestions on which subroutine can read the CPRESS (CSTRESS) as input information.

Many thanks!

SIMPLE ACOUSTICS PROBLEM

DEAR all

I want to knowthe following:

A circular diaphragm of 1mm diameter, is vibrating with the amplitude of 100 microns at frequency 1000 Hz. What is the sound output at 10 mm distance??

Shuze Zhu's picture

Pseudomagnetic Fields in a Locally Strained Graphene Drumhead

Recent experiments reveal that a scanning tunneling microscopy (STM) probe tip can generate a highly localized strain field in a graphene drumhead, which in turn leads to pseudomagnetic fields in the graphene that can spatially confine graphene charge carriers in a way similar to a lithographically defined quantum dot (QD). While these experimental findings are intriguing, their further implementation in nanoelectronic devices hinges upon the knowledge of key underpinning parameters, which still remain elusive.

Variation of Stress with Charging Rate due to Strain-Rate Sensitivity of Silicon Electrodes of Lithium Ion Batteries

Silicon is a promising anode material for lithium-ion batteries due to its enormous theoretical energy density. Fracture during electrochemical cycling has limited the practical viability of silicon electrodes, but recent studies indicate that fracture can be prevented by taking advantage of lithiation-induced plasticity. In this paper, we provide experimental insight into the nature of plasticity in amorphous LixSi thin films. To do so, we vary the rate of lithiation of amorphous silicon thin films and simultaneously measure stresses.

Leon Mishnaevsky's picture

Micromechanics of hierarchical materials: a brief overview

A short overview of micromechanical models of hierarchical materials (hybrid composites, biomaterials, fractal materials, etc.) is given. Several examples of the modeling of strength and damage in hierarchical materials are summarized, among them, 3D FE model of hybrid composites with nanoengineered matrix, fiber bundle model of UD composites with hierarchically clustered fibers and 3D multilevel model of wood considered as a gradient, cellular material with layered composite cell walls.

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