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Haimin Yao's picture

Science Channel Tonight at 9:00pm

Dear Colleagues,

May I have your attention please? It's air time for the second episode of "Popular Science's Future of...Combat".  The show will air on The Science Channel (science.discovery.com) at 9pm ET/PT on 9/07/09. The research on biological armors by Christine Ortiz's group from MIT will be reported.

Enjoy.

 

4th international confrence on Artificial intellegence

4th Indian International Conference on Artificial Intelligence (IICAI-09). IICAI-09 will be held during December 16-18 2009 in Tumkur (near Bangalore), India. IICAI is a series of high quality technical events in Artificial Intelligence (AI) and is also one of the major AI events in the world.

How to implement the Cohesive Zone Model in COMSOL?

Dear all,

I am trying to simulate a three-laminated composite considering the cohesive effect between the interfaces.

How can I implement this in COMSOL? Are there any Samples to follow? 

Thanks!

Binglun

Nanshu Lu's picture

The effect of film thickness on the failure strain of polymersupported metal films

We perform uniaxial tensile tests on polyimide-supported copper films with a strong (111) fiber texture and with thicknesses varying from 50 nm to 1 μm. Films with thicknesses below 200 nm fail by intergranular fracture at elongations of only a few percent. Thicker films rupture by ductile transgranular fracture and local debonding from the substrate. The failure strain for transgranular fracture exhibits a maximum for film thicknesses around 500 nm.

Disk vs blade natural frequencies

I'm trying to determine the coorelation of a blade natural frequency and disk (nodal diameter) natural frequency on a Turbine wheel in ANSYS Modal analysis.  Is it possible for a blade natual frequency to be excited even though a disk natural frequency is not being excited??  I'm having trouble determining if a blade frequency is related to any disk nodal diameter.  Thanks for any incite on this subject.

Zhijun Zheng's picture

Two positions for guest researchers(post-doc) at NIST on biomechanics

 Closed!!!

Two positions for guest researchers(post-doc) at NIST on biomechanics

Email: martin.chiang@nist.gov
Homepage: http://www.nist.gov/msel/polymers/biomaterials/martin_chiang.cfm
Research area: Biomechanics

Practical and graphical remarks about Moving Least Squares

I have had some time to write down an informal introduction to Moving Least Squares, from my coding perspective. It is supposed to be a condensation of experiences after some years of using it, although it does not contain any new theoretical aspect.

http://www.scribd.com/doc/19409754/yanrMLS

Hung Nguyen Huu's picture

I would like !!

Dear,

I would like to

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a fracture problem

  Dear everyone

  If we considerer a 3D fracture stress and strain field as a combination of numerous 2D fields in thickness direction, the J integral at each 2D plane can be obtained according to Rice’s definition (Abaqus and Ansys also include this function). What I concerned is the ratio of J integral at the surface of SEB or CT specimen to that at the mid-plane of the specimen. What factors have influence on the ratio? How to find the quantitive relationship between the factors and the ratio in linear elastic model?

Understanding continuity

Worth reading

 http://www.dpmms.cam.ac.uk/~wtg10/continuity.html

in case you need to explain the epsilon-delta  definition of continuity to an engineering student.

-- Biswajit 

fhuera's picture

PhD STUDENTSHIPS:FLUID STRUCTURE INTERACTIONS IN MARINE ENGINEERING AND IN BIOINSPIRED DESIGN

The Department of Mechanical Engineering at the Universitat Rovira i Virgili (URV) (www.urv.cat) in Tarragona (Spain), is looking for several enthusiastic research students with a strong interest in fluid dynamics. Successful candidates will join a small but very active multidisciplinary team, working in fluid-structure interaction problems. The research will be mainly experimental and focused in the area of fluid structure interaction with application to several engineering problems.

Input Steel Properties in Abaqus

Hi,

 

I am trying to model a reinforced concrete element in Abaqus. I have been running a couple of models for a few weeks. Recently, I tried to validate an new experiment but ran into this error, "The Plastic Strain At First Yield Should Be Set To Zero". For my steel material model, i used elastic = 29520ksi and for the plastic, i keyed in the yield stress followed by the plastic strain. At the first input, plastic strain is zero for the initial yield stress. 

Mario Juha's picture

Why ANSYS not ABAQUS?

I would like to know why ABAQUS is the dominant FEM program (in terms of comments) in this forum? Why do you consider ABAQUS over ANSYS?

I have been using ANSYS for at least 8 years and I am very please with the capabilities of it. But I have not seen ABAQUS or used it. Beside, reading all the comments that are posted in imechanica, I feel like I am using the wrong FEM program. 

Which are the advantage of ABAQUS over ANSYS?

 

Thank you,

 Mario J . Juha

www.eng.usf.edu/~mjuha/

Modeling Nitinol

Hello,

I'm new in this forum and I've a problem that i can't resolve.

I need to model nitinol in Abaqus: I've red the documentation and many topic in Internet but I don't understand if I must use a VUMAT subrutine or it is sufficent the tool of user defined material in Abaqus/CAE. I need something simple like an elastoplatic behaviour with hysteresis given by the different states of austenite and martensite.

Thanks in advance,

 Jam3s

Open Call for Journal Club Themes and Discussion Leaders

Attention all iMechanicians!  If you have a theme you would like to see in the Journal Club next year, please feel free to:

  1. post it here for discussion
  2. send it to me via email
  3. reccommend discussion leaders

Thanks in advance!

Konstantin Volokh's picture

Journal Club Theme of September 2009: Elasticity and Failure

Let us consider interaction of two atoms/molecules/particles. The reference distance between them corresponds to zero interaction force and zero stored energy. The interaction passes three stages with the increase of the distance. At the first stage the force increases proportionally to the increasing distance: the linear stage. At the second stage the force-distance relationship deviates from the linear proportionality: the nonlinear stage. At the third stage the force drops with the increasing distance: the separation or failure stage.

16th US National Congress on Theoretical and Applied Mechanics

The Congress will be held on 27 June – 2 July 2010, at the Pennsylvania State University.  The deadline for submitting abstract is 15 October 2009.

Pradeep Sharma's picture

The origins of electromechanical indentation size effect in ferroelectrics

The attached paper was recently accepted for publicaiton in Applied Physics Letters. Here we try to speculate on the origins of a type of electromechanical indentation size-effect. Although we have decent supporting evidence, I think that our assertions are still on the speculative side and hope that future experiments can shed further light on this.

Pradeep Sharma's picture

Revisiting Quantum Notions of Stress

I plan to submit the attached paper on quantum mechanical definition of stress in the next few weeks. Comments and feedback are welcome. Fair amount of work has been done on stress definition in the context of classical molecular dynamics (also attracting some controversies). In contrast, there appear to be several open issues in the quantum case. Hopefully, the attached paper provides a starting point.

tadmor's picture

Multiscale Postdocs at Minnesota

Several postdoc positions are available immediately at the University of Minnesota to work on the development of a variety of cutting edge multiscale methods and atomistic simulation techniques.  The work will be done in close collaboration with a group of leaders in the field including Prof. Ellad Tadmor, Prof. Richard James, Prof. Mitchell Luskin and Prof. Ryan Elliott.  For more information, visit www.multiscale.umn.edu or check out the attached announcement.

Green-Lagrange Strain Components

How can it be proved that the Green-Lagrange strain components include the rigid body motions?

Jean H. Prevost's picture

Postdoctoral position at Princeton University

Postdoctoral position available at Princeton University to participate in a multi-disciplinary research project sponsored by the US Army Research Office (ARO/MURI) at Princeton and Harvard Universities on: Innovative Design of Multi-Functional Adaptive Structural Materials. The candidate will be involved in the Modeling of Hierarchically Porous Material Structures Optimized for Strength and Transport. The candidate must have a strong background in Finite Element Analysis (both solid and fluid), and in Topology Optimization.

3rd International Conference on Mechanics of Biomaterials & Tissues - program now available!

Program for the 3rd International Conference on Mechanics of Biomaterials & Tissues now available at http://www.icmobt.elsevier.com/programme09.htm

Plenary and keynote speakers include:

Professor Julian Vincent, Professor of Biomimetics, Bath University, UK
-Stiffness and toughness of biological materials

Free Online Mechanics of Materials Textbook

I have posted the second edition of my book “Mechanics of Materials” online for free educational use. The book was reviewed and checked for accuracy by 30 faculty across the USA and was line edited by a professional editor.

The preface in the book describes the objectives and the design of the book, with details elaborated further in “Note to the Instructor”. The “Note to the Students” elaborates the many pedagogical features of the book. All these are in the file labeled “Table of content and front end material”.

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