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Nondetermistic material models

I am currently working on design optimization of nondeterministic systems and
would like to find realistic tolerances for the values of material
properties.  Does anyone know of a (standard) reference for material
values that is probabistic or at least shows a range of values?

PLATE WITH CRACK

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i have relations for tensile and bending stress in a rectangular plate due to a central surface crack for a constant thickness plate . i need to have these relations for a varying thickness plate . can any body help.

How to use ansys to model the tangential deformation of a rotating blade.

Dear all,

I have one question here. A blade is mounting on a rigid disk's outer rim. The disk is rotating at a variable angular speed. The system is  used to model a turbine wheel with a blade mounted on it when the engine is ramping up or shuttng down.

The thing I want to calculate is the blade tip deformation in tangential direction during this engine ramp up -steady state -shut down process. Does anybody know how to use ANSYS to model it?

Aman Haque's picture

Symposium on Multi-physics of Materials and Interfaces @ USNCTAM 2010

Dear Colleagues:

As a part of the 16th US National Congress of Theoretical and Applied Mechanics conference (from June 27 to July 2, 2010 at Penn State University), we are organizing a symposium on the multi-physics, or the coupling among physical domains (thermal, electrical, mechanical, magnetic, optical, chemical to name a few).

Arash_Yavari's picture

A Geometric Theory of Thermal Stresses

In this paper we formulate a geometric theory of thermal stresses.
Given a temperature distribution, we associate a Riemannian
material manifold to the body, with a metric that explicitly
depends on the temperature distribution. A change of temperature
corresponds to a change of the material metric. In this sense, a
temperature change is a concrete example of the so-called
referential evolutions. We also make a concrete connection between
our geometric point of view and the multiplicative decomposition

Publicly-available fatigue test data

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Can anyone help point me to publicly-available fatigue or fracture test data? I am interested in obtaining a variety of data for statistical processing. It seems many authors have used the data collected by Virkler and Hillberry which seems to be widely used, but I have not found raw data for their tests so far; is this data available somewhere for me to use? Any help is very appreciated.

Henry Tan's picture

Journal Club Theme of December 2009: Impact Behaviour of Materials with Cellular Structures

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Welcome to the forum! Discussion topics were suggested initially as follow:

Metal foams, cell deformation (bending, buckling, plasticity and fracture), constitutive stress-strain behaviour of cellular materials, energy absorption, hypervelocity impact, shock wave behaviour, 1D shock modelling, shock attenuation, shock enhancement, Material Point Method (MPM) simulation and microscopic tomography experimental observation;

and later were extended to many related:

Zhigang Suo's picture

A new Technical Committee on Soft Materials

A growing number of mechanicians are entering the field of soft materials, such as polymers, gels, and tissues. While they interact with researchers in technical societies traditionally identified with the field, they also maintain connection with researchers in applied mechanics.

VUMAT for Nitinol --- why VUMAT and not UMAT?

Dear all,

 I'm new in imechanica. I need some informations about VUMAT for Nitinol. I would like to implement in fortran a subroutine for the behaviour of shape memory alloy.I looked for some subroutines already implemented but they have been developed in the implicit way.

It's true that with the VUMAT(explicit) I could have some problems of stability and convergence.Could someone suggest me any reason to make this model in the VUMAT?I know that in VUMAT I can't redifine the time increment so before running the analysis It's important to pay attention on Dt.

Fracture mechanics

hi all..

 

i am having one doubt, please help me.

 

In a isotropic plate,  if crack tip is present then to model the crack tip we use quarter point element ( IN ANSYS).

if we wants to model more than one crack tip than ,, ansys will give following error

" Only one stress concentration can be specified per area"

Please let me know what is the procedure to model more than one crack tip.

Thanking you

vinaya 

 

vinay.kumar233@gmail.com

 

Help needed with interpretation of received P h curves during NANOINDENTATION

Dear iMechanicas,

 

I just started doing nanoindentation tests on dry biological samples (wood) with a flat punch tip and I have problems analyzing the results! I would be happy if anybody could give me some suggestions.

While running a test I receive quiet good force-displacement curves (no adhesion, good surface find, no time-depend behavior) but the values for the recieved elastic modulus are not stable! The value scatters over the whole range of displacement.

modelling of rectangular composite plates using ANSYS

I have to analyse the carbon/epoxy composite laminate in ANSYS,  to determine the natural frequency of rectangular composite plates. The plate is simply supported . I  am not able to model the composite lay up with the correct orientation of the fibre. so any body have the step by step procedure for modelling the composite lay up in ANSYS and how to determine natural frequencies  please give it to me on my e-mail:  sharma_avadesh@yahoo.com

plastic analysis of a plate containing an edge notch and a piezoelectric inhomogeniety with ansys

Hi,

I am rojin ghandriz,study M.c civil engeeniring at sharif university in iran,

I study on my tesis a bout plastic analysis of a plate containing an edge notch and a piezoelectric inhomogeniety.

I have questions a bout the crack initiation in Ansys v11.0..How could i get initiation of crack whit increasing tensile loading on plate in ansys?

thanks

rojin

Ning Wang's picture

Rac activation by stress does not depend on Src

It is known that platelet derived growth factor (PDGF) induced Rac activation depends on Src activity. However, we find that a local stress of physiologic magnitude via integrins can directly activate Rac GTPase rapidly, independent of the Src activity. Our finding on the stress-induced rapid Rac activation challenges the conventional wisdom on mechanotransduction and suggests that stress-induced signaling via focal adhesions does not follow signal transduction pathways induced by growth factors. To view the whole paper:

Hydrostatic stress as Fracture/Damage criterion?

Hi all,

       Can Hydrostatic stress be used as a fracture criteria? If so can critical hydrostatic stress be found experimentally? Thanks.

Two post-doctoral researcher positions in computational materials sciences available at Academia Sinica in Taiwan

Two post-doctoral researcher positions focusing on the two topics listed below are available immediately at Research Center for Applied Sciencs at Academia Sinica (中央研究院) in Taipei, Taiwan.

1) Ab initio MD simulations of Li ion diffusion on / inside novel electrode materials using accelerated MD. Candidates with expertises in ab initio MD, in particular, BOMD,  are highly desirable.

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?

Thermo-mechanical Modeling of Friction Welding

We present an application of ADINA in the thermo-mechanical analysis of friction welding. Please see: 

http://www.adina.com/newsgH61.shtml

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

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

Sakdirat Kaewunruen's picture

Civil Engineering Conference in the Asian Region and Australasian Structural Engineering Conference 2010

Civil Engineering Conference in the Asian Region and Australasian Structural Engineering Conference 2010

The 5th International Civil Engineering Conference (CECAR5) hosted by Engineers Australia, together with the Australasian Structural Engineering Conference (ASEC 2010) will bring together a broad cross-section of the civil and structural engineering professions who want to learn, network and advance their technical skills.

Two-point Tensors

I am confused about the use of two-point tensors in elasticity. The deformation tensor F and first PK tensor are two point tensors, and the "two-point" property arises from use of two different Coordinate System When a continuum body is deformed, why it is necessary to move the Coordinate System as well? (or alternatively, why the coordinate system is attached to the body itself??, isn't it possible to use a general coordinate system which can represent the deformations and also account for the rigid body rotations of the continuum body?).

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