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Help with surface stress on microcantilever

Hi all,

I'm a PhD student with Electronics Engineering background. I'm doing a research in microcantilever based biosensors.

I'm having difficulties in understanding the adsorption-induced stress in microcantilever.

I would appreciate any advice or pointers on what materials that I can refer to. Besides that, what is the software that I can use to simulate this adsorption phenomenon? 


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.

Sprunger's picture

Abaqus 6.9 release has XFEM

Hi All,

The new Abaqus 6.9 release offers new capabilities for fracture and failure (XFEM) and much more.

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?

ennio curto's picture

NDE residual stress

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More information about residual stress tester

In search of articles on mesoscale FE modeling of sintering

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Hi. I'm now starting my PhD on a project on sintering of hard metal.

I'm doing a literature study, but I have failed to find any articles that uses FE analysis on the micro/mesoscale. All of them seems to handle this only with a homogenized model on the macroscale.
If I get to be picky, I would prefer something with hardmetal, but at this point, anything would be great.
I would also be very happy to find any suitable reading on FE-analysis on solid-liquid-pore mixtures.

Failure Surface Graphics in Stress Space

 A new section has been added to the website on failure criteria for engineering materials.  This new work displays many different three-dimensional computer graphics of failure criteria surfaces in stress space. The full range of isotropic materials are covered from ductile metals to brittle ceramics and glasses and beyond.  All of these computer generated graphics can be seen at


Jianliang Xiao's picture

Prof. Ares Rosakis has been elected to a fellow of the American Academy of Arts and Sciences, 2009

Solid mechanician and Caltech Faculty Member Named to American Academy of Arts and Sciences: Caltech professor Ares Rosakis, is among the 210 new fellows elected to the American Academy of Arts and Sciences this year. They join an assembly that was founded in 1780 by John Adams, James Bowdoin, John Hancock, and other scholars to provide practical solutions to pressing issues.

Stroh formulation

I want to know about the basics of stroh fromulation and its application in Piezoelectric material.I didn't find the basic lecture notes or the material regarding that on the internet.

kuldeep sharma 

Geometric non-linearity basic question


I've been reading the book on Non-Linear Finite Element Analysis by Crisfield and have the following questions:

1.Considring the equation 1.10 in Crisfield's book on page 4, it is:

Kt = EA/l (z/l)^2 + EA/l (2zw + w^2/ L^2) + N/L


Kt->is the tangent stiffness matrix
z->in itial displacement
L->Length of the bar-as an approximation the undeformed length of the bar is considered.
N->internal force in the bar.

Ajit R. Jadhav's picture

What Platform Would You Prefer for a Software That Helps in Learning FEM---Windows or Java?

Ideally, this post of mine should carry a poll, but I guess as an ordinary user, I cannot insert one.

Currently, I am writing a small software program that is especially designed to help learn FEM. For instance, I will be providing detailed listings for every intermediate step, e.g. all those [D], [B], [k], etc. matrices for each element, as well as the final assembled global system {F} = [K]{d} and its solution separately at each Gauss point. Only linear static problems for the time being; will add transients/eigenvalue problems in near future.

Arash Massoudieh's picture

Post Graduate Researcher or post doctoral position in developing fish life cycle model

Post doctoral associate or post-graduate researcher position is available in the Department of Civil Engineering at the Catholic University of America ,Washington, DC. The candidate should be proficient in C++ programming and OOP concepts and preferably (but not necessarily) GIS applications. PhD degree is not necessary. The project involves developing an agent-based fish life cycle model for San Francisco Bay and Delta.

Thermal Ratcheting in Cylindrical tubes

Hi ,

Due to  Thermal ratcheting in cylindrical pipes carrying hot fluids that are used in nuclear applications, the pipe bulges. I am about to start a project to study why this bulge comes and how to rectify it. It would be very helpful to me if  some of you can give your valuable suggestions and references in the area of Thermal Ratcheting in pipes.

Thanks and Regards,


Arash_Kheradvar's picture

Effect of Fiber Geometry on Pulsatile Pumping and Energy Expenditure

Myocardial fiber orientation is a topic that has recently received much attention in connection with cardiac pumping function. The twisting motion of the cardiac base to apex can be a direct result of this geometric orientation of these fibers. One important question that has not been addressed yet is whether there is any relationship between the contractile energy expenditure and the geometric orientation of myocardial fibers. In the present work, we study the effect of contractile fiber orientation on pumping function.

Strain Based Fracture Mechanics

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Can anyone give me some tips within strain based fracture mechanics. My problem is predicting the fatigue life of a gusset speciemen, using strain based FM. I have read some litterature, but have problems on understanding the order of calculating, and methods of solving the equations. If anyone could help me understanding, I would be greatful.


Sean Angus

Nanshu Lu's picture

Singular stress fields at corners in flip-chip packages

An electronic device integrates diverse materials, and inevitably contains sharp features, such as interfaces and corners. When the device is subject to thermal and mechanical loads, the corners develop intense stress and are vulnerable sites to initiate failure. This paper analyzes stress fields at corners in flip-chip packages. The stress at a corner is a linear superposition of two modes of singular fields, with one mode being more singular than the other. The amplitudes of the two modes are represented by two stress intensity factors of dissimilar dimensions.

Ken P. Chong's picture

MRI-R2 has been posted

The NSF Major Research Instrumentation Program (MRI-R²) Recovery and Reinvestment is now posted. This is a good way to build up the needed major research instrumentation

The deadline for proposals will be August 10, 2009.

A link can be found through the page (preferred to keep abreast of updates) or through the NSF-wide page at

WaiChing Sun's picture

potential functional for material exhibts non-associative elastoplastic response

Does anyone knows where I can find any paper discuss the existence of potential functinoal for materials that violate the maximum plastic dissipation principle (due to non-convex yield function and/or non-associately fluw rule)?

Geometric non-linearity:Incremental (Euler) solution


Geometric non-linearity:Incremental solution

1.I've been reading the book by Crisfield on Non Linear finite element analysis and have just started with the first chapter wherein the author introduces geometric non-linearity.

I have some questions on the incremental (Euler) approach here:

I want to know whether my inetrpretations below are correct:

1)The incremental approach makes use of the tangent stiffness which relates small changes in load to small changes in displacement.

Teng Li's picture

Faculty Position in Fluid Mechanics at University of Maryland

Assistant Professor, Fluid Dynamics

Department of Mechanical Engineering
A. James Clark School of Engineering
University of Maryland, College Park

I want to choose a book on Tensor Analysis

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Tensor analysis is a very useful tool for continuum mechanics as well as other courses. I wonder which book is best for me. 

I have background of anvanced mathematics, linear algebra.  The book should be comprehensible.

Learning Continuum Mechanics

I would like to make a career in Finite Element MEthod with concentration on topics like XFEM,Mesh-free methods--

However, I am yet to mmake a start.To give you my background I ahve a good knowledge of subject of Strength of Materials,Linear Finite Element Analyis-including coding structrial analysis involving beam elements,plate elements,plane stress and plane strain elements-all linear FE.

I have good programming skills-C,VB,MathCAD and know basis of C++ well

I havee just undergone a course on Linear Algebra through the MIT opencourseware.

Does anyone use FEAP here?

Hi everyone,

Does anyone using feap software?

Currently I'm attempting to compiling FEAP at Visual Studio.  After I successfully building of both library and executable,

It shows "========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========".  I considered this as a successful compilation.

However when I run in command prompt: feap -itherm_2d  (It's the 5th example input file in FEAP software),  the errors pops up as :


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