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Jie Wang's picture

Effect of electrical boundary conditions on the polarization distribution around a crack in a ferroelectric single domain

Polarization distributions around an open crack with different electrical boundary conditions in a single crystal ferroelectric are investigated by using a phase field model. The surface effect of polarization is taken into account in the phase field model, which has not been included in previous ferroelectric crack models. The simulation results show that the impermeable crack and the crack filled with air have a significant influence on the polarization distribution, while the permeable and the crack filled with water have little influence.

anand_mtech's picture

mathematical model for a crack emanating from one rivet hole and approaching another

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Hi All,

 

i am doing my m. tech project on " FE modeling and validating to find stress intensity factor for a crack emanating from one rivet hole and approaching another rivet hole".I have developed the FE model in ANSYS and tabulated stress intensity factor at crack tip from different crack length. But to validate my result i want an mathematical model or formula. Please suggest me an formula to find KI at the crack tip for this problem.

what are the new recent advances in meshfree methods

i'm in my first year of doctorat level, and i work on meshfree methods applied in mechanical field, i would ask for recent research in this field and some indications for : what new to explore (composit materials, crack and fractures, other new materials...) in this field

phunguyen's picture

interface element

Taxonomy upgrade extras: 

Surface mediated plasticity in sub-10-nm-sized gold crystals

Nature Communications 1, Article number:144 | DOI:10.1038/ncomms1149

Although deformation processes in submicron-sized metallic crystals are
well documented, the direct observation of deformation mechanisms in
crystals with dimensions below the sub-10-nm range is currently lacking.
Here, through in situ high-resolution transmission electron
microscopy (HRTEM) observations, we show that (1) in sharp contrast to
what happens in bulk materials, in which plasticity is mediated by
dislocation emission from Frank-Read sources and multiplication, partial
dislocations emitted from free surfaces dominate the deformation of

ansys

 

Hello every body.

                             i ve a very simple question regarding ansys. can anybody can suggest how to mesh the glued area.what is the best element to use for adhesive bonding for 2d case

Cohesive strength theory ?

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What is the “cohesive strength” theory?

What are the differences in the energy consumption processes near the tip of a crack in plain concrete, fibre reinforced concret

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What are the differences in the energy consumption processes near the tip of a crack in plain concrete, fibre reinforced concrete and metals?

Sébastien Turcaud's picture

Inverse eigenstrain analysis based on residual strains in the case of small strain geometric nonlinearity

Hi,

I was wondering if someone knows literature related to "Inverse eigenstrain analysis based on residual strains in the case of small strain geometric nonlinearity"? (elongated bodies)

In the case of lineralized elasticity I guess one could postulate an eigenstrain distribution as the sum of a finite set of basic eigenstrain distribution and minimize the difference between the predicted and the actual residual strain distribution (retrieved from a synchroton mapping for example).

As done in the paper:

Turning a shaft through conact pressure in ABAQUS/standard?

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Hello all,

This is my first post here. This seems be an informative and helpful forum.

I am trying to model the rotation of a "hard" shaft as a result of motion of 2 strips of soft materials (please see attached figure).

The strips are deformed due to external forces and as a result, contact pressures are applied on the shaft. The forces are then varied on the strips leading to net rotational forces on the shaft.

SiC tri-axial data

I want to simulate scracthing of SiC material using drucker-prager model.

Where can i get tri-axial data to get the parameters of drucker-prager?

Or is there any other way to define the parameters?

Ning Wang's picture

Mechanics dictates embryonic stem cell pluripotency

We demonstrate that a soft substrate of a stiffness that matches the embryonic stem cell stiffness can promote homogenous self-renewal and pluripotency of these cells, even in the absence of the growth factor-Leukemia Inhibitory Factor (LIF). These findings open the field of stem cell biology for long term culture of embryonic stem cells without generating a heterogeneous population of cells with varying degrees of differentiation and highlight the importance of mechanics in dictating embryonic stem cell pluripotency.

NON-LINEAR BUCKLING PROBLEMS

Dear Research Comminity,

Please upload a few problems in non-linear buckling problems and solving procedure using ABACUS which helps me to understand the procedure and ABACUS.

Advance Thanks

Zhigang Suo's picture

Worldwide Electroactive Polymer Newsletter

The latest issue of the WW-EAP Newsletter is now available.  I’m pleased that the issue includes my submission on a recently completed review on the Theory of Dielectric Elastomers.  As usual, the Newsletter contains lots of extremely valuable information, such as new books in the field, and new products.

Twitter

You are welcome to follow my updates on Twitter:

 http://twitter.com/LeeMargetts

Soil Mechanics and Fossil Dinosaur Trackways

My PhD student Peter Falkingham (who graduated 15 December 2010) has published some interesting papers on Dinosaur Trackways. These might be of interest to those teaching Soil Mechanics, to give some examples that might be more stimulating than foundation design or traditional geotechnical engineering.

References below:

Falkingham P.L., Bates K.T., Margetts L. and Manning P.L. (2011) "The 'Goldilocks' effect: Presevational bias in vertebrate track assemblages", Journal of the Royal Society Interface, accepted for publication. Impact factor 4.241.

ABAQUS:Negative Pressure with “Hard” Pressure-Over Closure

Hi,

I'm using ABAQUS for my research o soil-pile interaction. For the initial modeling of soil-pile interface I have used the "Hard" pressure-over closure relationship. According to the definition negative pressure is not possible with that type of normal contact behavior. But when I check the contact pressure still I can see that negative pressure is applied. What could be the reason?

Thanks,

Thanu

Varying material properties spatially in ABAQUS

Hi,

In an ABAQUS 2D-planar model, is it possible to vary the material properties spatially, say defining modulus (E) as a function of coordinates, E = f(x,y)? One way is to use *DISTRIBUTION feature, but that allows variation based on element-sets and does not allow varying the material properties as function of coordinates. If anyone has solved this or similar problem kindly suggest.

 

Thank you

Vaibhav

Yuli Chen's picture

Fracture Toughness of Carbon Nanotube-Reinforced Metal- and Ceramic-Matrix Composites

Hierarchical analysis of the fracture toughness enhancement of carbon nanotube- (CNT-) reinforced hard matrix composites is carried out on the basis of shear-lag theory and facture mechanics.

ravitejk4u's picture

Contact issues in abaqus

Hi All,

I am dealing with contact problems. Can you please post if you have any information on how to resolve the general contact problems.

 thanks and Regards,

Ravitej

Virtual Heart Surgery

1. We highlight a study performed by researchers using ADINA in which they investigated a computational approach to construct patient-specific ventricle models based on in vivo cardiac magnetic resonance (CMR) imaging for surgical planning and optimization. The study was motivated by the fact that the use of such computational models can help to assess different surgical hypotheses and replace empirical and perhaps risky clinical experimentation. For more information please see

http://www.adina.com/newsgH81.shtml

How to get the uncoupled natural frequencies

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Hello Everybody,

A wing was simplified with 8 dumbbelss or concentrated mass. The weight of the 8 dumbbells are:

{W}=[1.240 1.050 0.964 0.862 0.733 0.628 0.634 0.457]T

The static unbalance is:

{SA}=[0.2680 0.2910 0.1810 0.1610 0.1220 0.0884 0.0854 0.0598]T

The moment of inertia is:

{IA}=[0.412 0.437 0.272 0.230 0.157 0.143 0.115 0.055]T

The flexibility  influence coefficience for torsional and bending shape is also known, using [CTT] and  [CZZ] for torsion and bending respectively.

The Mass matrix is diagonal:

drying modeling in abaqus

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Good morning

I'm working in Abaqus on drying modeling. Regards this i have two questions.

1)Drying modeling is possible in Abaqus

2)I would like to ask if it is possible for Abaqus to model drying how can i create automatic crack propagation in 2D or 3D

P.S. sorry for my english, i hope everything is clear enough to understand this post. i hope someone can help me.

Regards

Vikram Gavini's picture

A Field Theoretic Approach to the Quasi-Continuum Method

Dear Colleagues,

I wish to bring to your attention my recent work with Mrinal Iyer on a field theoretic approach to the quasi-continuum method to appear in Journal of the Mechanics and Physics of Solids. Below is the abstract and attached is the preprint of the article. I will very much appreciate your comments and suggestions.

A Field Theoretic Approach to the Quasi-Continuum Method

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