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Glass behaviour-viscoelastic or viscoplastic?

I am a bit confused about glass (silicate glass) material behvoiur. If it is viscoelastic how does it deforms? Does anyone knows any good reference?

 Thanks

FRacture Growth - Abaqus Explicit

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Hi,

        I want to model 3D crack propagation in Abaqus Explicit. For this I am thinking of using the *shear failure option with element deletion. The path of the crackin my models is not known. I have some basic questions in this regard.

 

1. Is *shear failure a good approach to model crack propagation ?

 

2. I am modeling crack growth in geological materials. Usually cracks propagate in the trail of a damage zone. Can this (damage zone) be reproduced in Abaqus Explicit with *shear failure option ? 

Thanks in Advance,

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Seeking a logarithmic operator for a 4th order tensor

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I don't know whether this question has an answer, but I'd like to see what you all think:

Does anyone know whether or not the following operation is meaningful, whether it is described and defined algorithmically somewhere, and / or how to do it?

ln(Aij) = Bkm ln(Cijkm)

A and B are second order tensors

C is a 4th order tensor

The left hand side involves the natural logarithm of the 2nd order tensor A, which is no problem. 

Is anyone here doing simulation on Carbon Nanotubes

Dear All,

I am new to simulations of carbon nanotubes, especially in their mechanical properties. My supposed tools are ab initio codes or md codes. I am looking for some references. Can someone introduce some classical papers or leading experts in this field.

Thanks.

Problems with FEAP compilations in Visual Studio 2008

I have a problem when a try to compile FEAP with visual studio 2008. The error is the next:

error #6633: The type of the actual arguments differs from the type of the dummy arguments.

I have tryed to compile several times but the error is the same.

I do not know if I have configure properly my visual studio or if it is a problem with mi FEAP.

 

Calculation of potential energy in conditions of prescribed displacement and prescribed loading

A question has arised when I read a book about fracture mechanics recently.

This question is about the calculation of potential energy in "fixed-grips" (prescribed displacement) and "dead-load" (prescribed displacement).

Stresses in Elastic Materials in Non-uniform Cooling

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Hi,

 

I am having confusions about the concepts of thermal stresses of an un-constrained elastic body when heated/cooled.

Let's say if I have an elastic body of an arbitrary geometry. If I subject it to a uniform temperature change without any constraints, then there will no thermal stresses at the end of the analysis. I guess I am right till here.

Guy M. Genin's picture

Journal Club Theme of June 2009: Bimaterial interfaces in nature: attachment of tendon to bone

The June journal club entry was written jointly with Stavros Thomopoulos  from the Department of Orthopaedic Surgery at the Washington University in St. Louis School of Medicine.

Corotational Elements / Methods

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I'm a MSc (Applied Math) student modelling vibrating bridge hanger cables using corotational method. I'm interested in chatting with anyone using this method, especially for cables/beams but also other contexts. Thanks, John.

New paper: Cloaking of matter waves under the global Aharonov-Bohm effect

Cloaking of matter waves under the global Aharonov-Bohm effect

Authors

De-Hone Lin and Pi-Gang Luan

Abstract

Obesco Gad's picture

Elastic-Perfectly Plastic in Abaqus Explicit

Dear Mechanical Engineers,

It's my pleasure to be one of your group. I have a question in Abaqus Explicit and all my friends recommended me to as iMechanica as the explicit Abaqus is more popular to you than us as civil engineers.

I’m trying to simulate a tensile test for an elastic-perfectly plastic material as a quasi-static analysis in Abaqus Explicit. I have solved the same problem in Abaqus Standard and the results were fine as follow.

Nonlinear oscillation of a dielectric elastomer balloon

This paper studies the dynamic behavior of a dielectric elastomer balloon subject to a combination of pressure and voltage.  When the pressure and voltage are static, the balloon may reach a state of equilibrium.  We determine the stability of the state of equilibrium, and calculate the natural frequency of the small-amplitude oscillation around the state of equilibrium.  When the voltage is sinusoidal, the balloon resonates at multiple frequencies of excitation, giving rise to superharmonic, harmonic, and subharmonic responses.  Whe

Xuxin_Tu's picture

geomechanics @ Northwestern featured in LiveScience

 

http://www.livescience.com/environment/090527-science-lives-andrade.html

LiveScience is a pretty cool initiative targeted to the general public,
specially the younger generations to communicate the impact and
value of science and the people around it.

Adrian S. J. Koh's picture

Maximal energy that can be converted by a Dielectric Elastomer Generator

Mechanical energy can be converted to electrical energy by using a dielectric elastomer generator.  The elastomer is susceptible to various modes of failure, including electrical breakdown, electromechanical instability, loss of tension, and rupture by stretch.  The modes of failure define a cycle of maximal energy that can be converted.  This cycle is represented on planes of work-conjugate coordinates, and may be used to guide the design of practical cycles.

Looking for a PhD Position in welding Engineering

I did my Master in Material Science from IIT Roorkee in year 2007. Worked on GMAW of steel to aluminum joint in ISF, Aachen University, Germany under DAAD fellowship. Joined in Tata Steel Research and Development Division, India. Working in the field of Welding and Joining. Work on Adhesive Bonding and Weld Bonding of Advanced High Strength Steel sheets for automobilr. Now working on MIG-Brazing of High Strength GA steel sheets for automobile and also work on Friction Stir Welding of EIF steel to steel and EIF steel to Aluminum alloy sheets. Now looking for a PhD position preferably in Europe to do research in Welding Area.

Abaqus 3D model and 2D meshed cross-sections

I have a 3D model in Abaqus of a wind turbine rotor, modelled with shell elements (S4R and S3). To use the same blade in an aeroelastic wind turbine code (HAWC2 from Risoe), I want to convert selected cross sections of the 3D model to Timoshenko beam elements.

Coupling Abaqus with an aeroedynamic code - PART 2

In a previous post some months ago (see here), I mentioned some of the questions I had considering the aeroelastic response of a wind turbine rotor. In this post I just want to give, for those interested, a brief status report.

Gibbs free energy and constitutive equations

I don't know if my understanding of the following is correct, so I would appreciate your comments. I have an expression for Gibbs free energy of a material G=G(σ,T,...). Is it correct to derive the equation for strain as ε=∂G/∂σ ?

Composite plate analysis using ansys. coding using matlab

hi friends,

 

 I  have coded for laminate  using matlab. for further analysis i want  code for composite plate simply supported at all 4 edges. 

 then analyse with ANSYS. and use optimization techniques for optimizing the plate.

material : Graphite /eposy

thickness of each lamina : 0.127

Seq [45 0 -45]

 

Please anybody know how to code for composite plate and do stress analysis using Ansys.

feel free to share ur thoughts 

soil modeling

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My name is Bash Phd  in colorado school of mines and I am newbie in soil modeling  and I just started my PhD study  months ago. I am experimentally and numerically studying the stress distribution undernath the padfoot roller at the first stage, I need to have a constitutive model for soil with both dilatancy and hardening behaviors.

zishun liu's picture

International Journal of Applied Mechanics (IJAM) Vol.1 No.2

Dear Colleagues:
I am pleased to inform you that the papers to be published in International Journal of Applied Mechanics (IJAM) Vol.1 No.2 will be online available soon.

IJAM Vol.1 No.2:
1.  “Postbuckling Of Nano Rods/Tubes Based On Nonlocal Beam Theory”, C. M. Wang (National University of Singapore); Y. Xiang (University of Western Sydney); S. Kitipornchai (City University of Hong Kong).

Fracture Mechanics vs. Damage Mechanics

I was wondering what are the advantages of damage mechanics and fracture mechanics over each other? Specially in order to model the delamination phenomenon.

please help for postbuckling analysis in ANSYS

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I am trying to perform postbuckling analysis of plates in ANSYS. But something confuses my mind. After linear buckling analysis I use scaled firtst buckling mode shape to generate initial imperfections. Then I initiate nonlinear geometric analysis by NLGEOM command. Collapse load or final converged iteration changes according to NSUBST option. I am trying to give higher Substep to obtain more sensitive and reliable results like 10000. But NSUBST with 100 sometimes reaches higher loads than using 10000. Which one is a correct approach?

Could anyone help me?

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