This paper reports the quantitative measurement of a full spectrum of mechanical properties of fivefold twinned silver (Ag) nanowires (NWs), including Young’s modulus, yield strength, and ultimate tensile strength. In-situ tensile testing of Ag NWs with diameters between 34 and 130 nm was carried out inside a scanning electron microscope (SEM). Young’s modulus, yield strength, and ultimate tensile strength all increased as the NW diameter decreased. The maximum yield strength in our tests was found to be 2.64 GPa, which is about 50 times the bulk value and close to the theoretical value of Ag in the <110> orientation. The size effect in the yield strength is mainly due to the stiffening size effect in the Young’s modulus.

Dear Colleague:

You are cordially invited to attend Nanobrücken II:  A Nanomechanical Testing Workshop, jointly presented by INM - Leibniz Institute for New Materials and Hysitron, Inc., with co-sponsorship from the JEOL company. This is the second workshop in the Nanobrücken series.

Hi all,

I am trying to use ABAQUS to study stress-strain distributions in a polycrystalline material. To this end, my first goal is to simulate elastic deformation (small strain) of a polycrystalline sample of an elastically anisotropic material. What I am looking for are some tutorials or case studies of polycrystal deformation, where I can learn how to set up and simulate polycrystalline deformations. I found lots of literature on plastic deformation of polycrystalline materials (mainly using crystal plasticity finite element method). I am not concerned with plasticity and would like to know if there are simpler programs (or subroutines) for elastic deformation of polycyrstals. Any suggestions are highly appreciated. Thank you for your time.

Hello Everybody, this is my first post here.

I am currently working on finding the analytical solutions of deformation of thin elastic ring on elastic foundation, with centre fixed. A radial point load is applied at a point. I have derived equations of motion, but i am stuck at boundary conditions. What will be the boundary conditions(BC's) here in rings? In beams, the displacements and moment/force at the ends were specified,(4th order equation and 4 BC's, so the complete solution)  but here its all absorbed in periodicity. Equation of motion came out to be of 6th order, for that i will be needing 6 BC's , I am unable to figure out what they will be.  

Can anyone please help? 

Read Dr Marcin Kaminski's (Technical University
of Lodz) September 2011 Editorial for ICE-journal Engineering and Computational Mechanics for free here.

Hi
all,

I am Mohammad Aramfard senior student of mechanical engineering and I joined this
great forum yesterday, so I am not very familiar with regulations and rules.

Dear Colleagues,

I would be glad to present symbolic-numeric CAE system for frame structures analysis.

It will be available soon as Preview version for enthusiasts

The main features are:

It is with great sadness that I report the passing away of Prof. Don Carlson. The link below describes his life and work.

http://mechse.illinois.edu/content/news/article.php?article_id=410

I would like to know simply how to solve efficiently elasticity problems with Neumann boundary conditions? Neumann bc implies that I have 6 null eigenvalues in 3D (3 in 2D) associated to rigid body modes  and iterative methods such has conjugate gradient are not likely to work (because the problem is no longer positive definite, but only semi-definite). Is there any way to use iterative solver anyway by filtering rigid body motions or something like that ? However has anyone a good idea to solve such problem? For now, fixing aribrarily the displacement of some nodes (3 in 3D but not aligned, 2in 2D) is the only way I see, but I would like to have your smart advise on the subject...

Thank you !

How can we derive dynamic beam equation from navier equation in elastodynamic? I tried with the displacement vector field:

u=-z*w(x,t)

v=0

w=w(x.t)

and put it in navier equation, but it does not work.

I am looking for a source which has a good explanation of the pill box argument to prove continuity of the traction vector. If you know of such a source (url, book etc) please let me know. 

Thanks,

-Nachiket

Hello There,

I'd like to discuss here my result about residual stress. I calculated with Abaqus a thermal transient from 20 to 300°C +relaxation(unconstrained, keeping the same final T=300°C) on a planar model of a composite material (simplified).  The 2 circles are tungsten (W), the Matrix is copper (Cu). Stress (eigenspannung) should arise from mismatch of expansion coeffiecients (CTE_W~0.3*CTE_Cu), but it should also desappear after relaxation, since circles and matrix are free to expand and both modeled as pure elastic phases. Despite the model is perfect elastic and free to expand in x and y (only BOTTOM nodes are fixed in y), I get non-zero stress across the region.

I am looking for stress and displacement fields for indentation of an elastic half-space with a rigid spherical indenter. Anthony C. Fischer-Cripps provides closed form expressions (no derivations) for stress fields in his textbook "Introduction to Contact Mechanics" (Chapter 5, Page 88-89). He cites the work of M.T. Huber[1] which is in German (Annalen der Physik, 1904). 

Can someone point me to an English language reference for the analytical derivation of displacement and stress fields in the interior of the specimen ?

Dear All,

 I think that many students are looking for some tutorials about writing a UMAT in ABAQUS.

You can find a comprehensive tutorial for elastic problems.

This file contains: 

• Motivation

• Steps Required in Writing a UMAT or VUMAT

An old book of elasticity with excellent and precise theoretical explanations. It is still valuable and inspiring book in elasticity up to now.

 Dear AllI has question about these stresses.1.Are deviatoric stress generate plastic deformation?2. Are hydrostatic stress generate plastic deformation?3.What is the advantage of transferring strain tenser orientation to the principle coordinate axes? 4. What is the difference between rupture and fracture stress?

Dear all,

Herewith I would like to announce that we have decided to make our CONTACT software publicly available. You can obtain a free copy at the web-site www.kalkersoftware.org. We hope that the software is beneficial to you. We further hope that you give us helpful feedback in return.

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.

I use the meshless Galerkin method for 3D simulation of plate movement. This method requires the volume integration over a test domain. Could somebody help me with the volume integration? I wonder if there are standard or open source algorithms that can be used for this problem.

I would appriciate any help.

The following is a (relatively minor) question which had occurred to me more than two decades ago. By now I have forgotten precisely when it was... It could have been when I was in my TE (third year engineering) at COEP. ... Or, perhaps, it was later on, when I as at IIT Madras (studying stress analysis on my own). ... I don't remember precisely when it occurred to me, only *how* it did---it was when I was poring over the first part of Dieter's book.

IMHO, a matter like this should have been explicitly dealt with by the undergraduate texts on solid mechanics / elasticity. But, none does. Without straining your curiosity any further, let me tell you what that (minor) problem is:

Hi

i like to run this Job.

would you please help  me.

 thanks

Dear Colleagues,

The deadline for submitting an abstract to the international
conference "Fluid and Elasticity 2009" is approaching.

   ABSTRACT SUBMISSION DEADLINE: DEC. 19

To submit your abstract, please follow the instructions on:
https://www.irphe.univ-mrs.fr/%7Efe09/abstracts.html

The following topics will be addressed:
- Aeroelasticity
- Biological internal flows
- Compliant walls
- Elasticity-capillarity coupling
- Flow-induced vibration
- Swimming/Flying
- Swimming of microorganisms
- Wind-plant interaction