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large deformation

Extrusion, slide, and rupture of an elastomeric seal

Elastomeric seals are essential to two great technological advances in oilfields:  horizontal drilling and hydraulic fracturing.  This paper describes a method to study elastomeric seals by using the pressure-extrusion curve (i.e., the relation between the drop of pressure across a seal and the volume of extrusion of the elastomer).  Emphasis is placed on a common mode of failure found in oilfields:  leak caused by a crack across the length of a long seal.  We obtain an analytical solution of large elastic deformation, which is analogous to the Poiseuille flow of viscous liquids.

rajan_prithivi's picture

Large Deformation - Definition of total work energy density

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Like we have the elastic strain energy density for small deformations  defined as 0.5* σ :e  .

Is the equation PK2:E valid for the total work energy density for elastoplastic regimes ? If not, what would be a valid equation for total energy density ?

How can we decompose total work density into elastic work and plastic work densities for a large deformation case.

Where,

PK2 is the second piola kirchoff stress tensor

E is the Green-Lagrange strain tensor

 

Thanks,

Prithivi

 

 

Shape Bifurcation of a Spherical Dielectric Elastomer Balloon under the Actions of Internal Pressure and Electric Voltage

Under the actions of internal pressure and electric voltage, a spherical dielectric elastomer balloon usually keeps a sphere during its deformation, which has also been assumed in many previous studies. In this article, using linear perturbation analysis, we demonstrate that a spherical dielectric elastomer balloon may bifurcate to a nonspherical shape under certain electromechanical loading conditions.

Davide Bigoni's picture

Elastica arm scale

Can configurational forces be exploited to design a new type of scale?

See the explanation and an example of use at http://www.ing.unitn.it/~bigoni/elasticscale.html

If you're having trouble playing videos on YouTube, click here to watch it.

 

Jiang Chen's picture

How to get the update the local material coordinate in large deformation for hyperelasitc rubber-like materials?


Hello, 


I want to ask things about the updation of local material coordinate in large deformation. 


Does there exist two ways for this?


1. Polar decomposition of Gradient Deformation Tensor F to get the rotation tensor.


2. Update each basis vector of local material coordinate system using modified Gradient Deformation Tensor F_bar = F*J^(-1/3).

PhD studentship position on "modelling of surface defects transformation in hot rolling of steel"

a PhD student ship is available for UK/EU nationals (ONLY) to develop a Finite Element model of the rolling
operation to predict the behaviour of surface defects on the rolled
material during hot rolling of steels. The effects of geometrical parameters along with the material
properties and the rolling geometry, such as bite angle, on the behaviour of
the surface defects during rolling will be investigated. The
project is partially funded by Tata Steel Europe, 

bazant's picture

Objective Stress Rates in Finite Strain of Inelastic Solid and Their Energy Consistency

In many practical problems of solid mechanics, it is sufficient to characterize material deformation by the small (or linearized) strain tensor. But there are also many problems where the finiteness of strain must be taken into account.

Cardboard rolls on the nanoscale

Everybody knows that cardboard paper can be a highly
anisotropic material. You can easily bend or roll it in one direction
and it is stiff in the other. If you take a close look you will find
that the paper is periodically buckled along one direction. We have now
exploited this phenomenon on the nanoscale to define the roll-up
direction of ultra-thin membranes on a substrate surface.

Disparity in Simple Shear solution in ABAQUS

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Dear All,

FSI Analysis to Understand Carpal Tunnel Syndrome

1. We present an interesting application of ADINA FSI in the study of carpal tunnel syndrome. The analyses involve large deformations and contact of multiple flexible bodies which are immersed in a fluid:

http://www.adina.com/newsgH71.shtml

2. Please recall that we offer a very attractive academic package, for research and teaching, for university users. For more information see

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

FSI Analysis of the Human Coughing Mechanism

We present an application of ADINA FSI in the study of the human coughing mechanism. The aim of the study is to help surgeons to position tracheal implants effectively. Please see

http://www.adina.com/newsgH69.shtml

You can find many other examples of applications of ADINA in the analysis of multiphysics problems here:

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

FSI in Cardiovascular Mechanics

We present an interesting application of ADINA FSI in cardiovascular mechanics, specifically, a potential cause for heart attacks is studied.  Please see     

http://www.adina.com/newsgH63.shtml

ANSYS Modelling 3D Surface-to-surface Contact, need help

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I am fairly new to ANSYS and have been trying to model the interaction between glass micro-spheres and silicone polymer micro-structures for my dissertation research.  I've been working through the online manual, but have been getting very odd results when running the simulation.  Any help at all would be appreciated.  The summary of my problem is as follows:

 Modelling:

It may help to first refernce the first two images at : http://bdml.stanford.edu/twiki/bin/view/Main/AnsysModelling

ALE (Arbitrary Lagrangian-Eulerian) mesh adaptivity in ABAQUS/Standard

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Dears,

 I'm doing some numerical analysis on penetration of infra-strucutres on soils (such as CPT tests) in ABAQUS/CAE .. what I'm recently challenging with is to overcome the element excessive distorsion due to large deformations... I have to apply contact constraints in my model...I would appreciate it if you share your expriences with me regarding the following tips:

1- Is it possible to use the ALE (Arbitrary Lagrangian-Eulerian) mesh adaptivity in ABAQUS/Standard? If yes, do you know of any accessible examples (.cae files) or references?

Fluid-structure Interaction in Cell Mechanics

We present an application of fluid-structure interaction analysis to the mechanics of red blood cells. For more information see the following link:

http://www.adina.com/newsgH60.shtml

Please recall that we offer a special academic package, for research and teaching, for university users. For more information see:

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

Bending and wrinkling as competing relaxation pathways for strained free-hanging films

A thin film subject to compressive strain can either bend (for large strain gradient) or wrinkle (for small strain gradient). The bending is traditionally used in thermostats (bimetal stripes), but couple of years ago, it was extended to the nanoscale thin films which can bend and roll-up to tubes with defined number of rotations. The wrinkles are also rather common in macro- and microscale thin films.
Here, we developed an equilibrium phase diagram for the shape of
compressively strained free-hanging films by total strain energy
minimization.

Wei Hong's picture

Large deformation and electrochemistry of polyelectrolyte gels

Immersed in an ionic solution, a network of polyelectrolyte polymers imbibes the solution and swells, resulting in a polyelectrolyte gel. The swelling is reversible, and is regulated by ionic concentrations, mechanical forces, and electric potentials. This paper develops a field theory to couple large deformation and electrochemistry. A specific material model is described, including the effects of stretching the network, mixing the polymers with the solvent and ions, and polarizing the gel.

Boundary conditions in corner nodes

Hello Dear

 

I have a problem about informing boundary conditions of a CFFF plate. How can I inform the boundary conditions of corner nodes?

With best wishes 

Details About "NLGEOM"Command in ANSYS

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I am developing an FEA code for a viscoelastic contact analysis. Right now the formulation is assuming small deformations. After deformation I am getting the volume of the body to be less than the original. I want to preserve the volume. ANSYS gives exact results as my code by carrying a normal contact analysis.

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