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How to deal with negetive plastic strain increment in FEA in an elasto - plastic problem

Submitted by Suman.Guha on

In case of elasto-plastic problem it is mentioned that unloading of an integration point should be started along the elastic moduli when the solution gives a negetive increment of the plastic strain at the integration point. If anyone could elaborate it a little more, it will be really helpful.

Thanks 

Wendtland (1972) experimental results on natural frequencies of cracked cantilever beams

Submitted by aysha.kalanad on

The effects of edge cracks on the natural frequencies of cracked cantilever beams have been extensively studied by Wendtland (1972). These results are referred to by quite a number of related journal papers; the refernce is:

Wendtland D. A¨ nderung der biegeegenfrequenzen einer idealisierten Schaufel durch Risse. Ph.D. Dissertation, University of Karlsruhe; 1972.

Does anyone know how this can be accessed online, or atleast the complete set of results for eigenfrequency (first three modes of vibration) changes due to edge cracks at different positions and depths?

Post Doc position available in hybrid design of armor panels (with ceramics, composites) @ NTU, singapore

Submitted by karthic_newbee on

There is a Post doctoral Position available with my supervisor Prof.Sridhar Idapalapati.  The candidate should have PhD degree with background in  impact mechanics, fracture mechanics and exposure to finite element modeling packages such as AUTODYN software. Exposure (handson) to drop tests or Hopkinson bar tests is an added advantage.

If u are interested plz contact him directly @ msridhar [at] ntu.edu.sg

 

Experimental Observations of Stress-Driven Grain Boundary Migration

Submitted by Tim Rupert on

My coworkers (Dan Gianola, Yixiang Gan, and Kevin Hemker) and I have published research results in the December 18th, 2009 issue of Science.  In this work, we perform tension tests on specially designed thin film samples to studying the influence of different stress and strain states on mechanically-induced grain growth in nanocrystalline aluminum.  Our results indicate that shear stresses drive grain boundaries to move in a manner consistent with recent molecular dynamics simulations and theoretical predictions of coupled grain boundary migration.

 

New methods of analyzing indentation experiments on very thin films

Submitted by Li Han on

Abstract - Indentation experiments on very thin films are analyzed by employing a rigorous solution to model elastic substrate effects. Two cases are discussed: elastic indentations where film and substrate are anisotropic, and elasto-plastic indentations where significant material pile-up occurs. We demonstrate that the elastic modulus of a thin film can be accurately measured in both cases, even if there is significant elastic mismatch between film and substrate. 

This manuscript has been accepted for publication in Journal of Materials Research.  

Help regarding Tutorials on Creep using Abaqus

Submitted by guptavk_70 on
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My research area is modeling of creep in MMC. I am trying to use Abaqus for this purpose but I am unable to find any tutorial that can provide me some help that how to use creep module provided in Abaqus. Will any body can help me by providing some tutorial related to that topic. It will be highly apprecioated.