In this movie taken at 1 Mfps using our new Kirana camera (courtesy Y. Rotbaum), one can see a dynamic tension test of a grroved specimen in a tensile Hopkinson bar. The groove is relatively sharp and 10% of the diameter in depth.
It so happens that the dynamic neck inception occurs outside the notch area, in other words a strong geometrical flaw does not dictate the failure locus. We have performed over a hundred of such experiments. This is a very interesting and challenging observation....
Re: Dynamic necking
That's an amazing video! What is your explanation ?
-- Biswajit
In reply to Re: Dynamic necking by Biswajit Banerjee
To Biswajit: Waves (plastic?) interaction and buildup of strain.
D. Rittel
merittel [at] technion.ac.il
rittel.net.technion.ac.il
In reply to To Biswajit: Waves (plastic?) interaction and buildup of strain. by D.Rittel
Re: Dynamic necking
Why then is the strain localized away from the groove? Do you think the groove is acting as a boundary and reflecting waves?
I have added this question to the list in Stack Exchange. If you find it difficult to reply on iMechanica you can post a comment on Stack Exchange. The link is http://area51.stackexchange.com/proposals/67726/theoretical-and-applied-mechanics/68904#68904 .
-- Biswajit
Sorry, I can't find how to reply to comments :=(
D. Rittel
merittel [at] technion.ac.il
rittel.net.technion.ac.il
Some additional info may be required:
What was the material tested ?
Was the location of the "extra"-neck approximately the same ?
Dimensions? Velocity?
I am curious about the test conditions, namely the velocity imposed and the dimensions of the specimen.
Matt Lewis
Los Alamos, New Mexico
In reply to Dimensions? Velocity? by Matt Lewis
everything is in our papers
www.rittel.net.technion.ac.il :=)
D. Rittel
merittel [at] technion.ac.il
rittel.net.technion.ac.il
D.
D. Rittel
merittel [at] technion.ac.il
rittel.net.technion.ac.il