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Equivalent strain in large torsional deformation

Submitted by AAGP on

Dear All

Looking for a methodology to convert shear stress-shear strain data from a torsion test in large deformations into true strain-true stress curve, I found two schools of thought: 

 

and

 

I found also in recent papers a strong debate on which should be the correct method. For example:

Comment_on_A_comparison_of_the_von_Mises_and_Hencky_equivalent_strains_for_use_in_simple_shear_experiments

Looking at references in the paper and simply searching with google about this topic, it is easy to find many papers where both schools of thought defend their positions. In your opinion, on the basis of current knowledge of continuum mechanics of finite deformation, which is the correct method?  

Thank you in advance  

The question is important and difficult to answer with the limited capabilities for writing equations that iMechanica provides.  It's to provide a forum where such questions can be answered (and answers improved over time) that I had proposed the Stack Exchange Q&A forum.

Many other important questions remain unanwered on iMechanica because of the following:

1) Writing a good answer takes times and a lot of thought

2) There is no direct benefit to answering questions on iMechanica

3) Why answer on iMechanica when one can publish a short paper on the topic instead.

-- Biswajit

Thu, 05/15/2014 - 22:00 Permalink