Yes - attached paper shows for example how to convert Burger's model into Prony series.
On Tue, Feb 21, 2012 at 9:08 AM, Robert Cimrman <cimr...@ntc.zcu.cz> wrote:
Quick googling told me, that Prony series is a sum of exponential terms with different decays, right? As such, a single term in the series IMHO directly corresponds to the ETH version of the fading memory term. One could simulate the whole series by adding several ETH terms. The TH terms are more general, as the fading memory kernel can by any (even weird) function.
Looking forward to the tutorial.
r.
On 02/21/2012 03:41 PM, Andre Smit wrote:
Brilliant!
I'm closing issues #172 and #114. When I get some time I'll work in a tutorial on these terms. A comparison with Abaqus that uses Prony series for viscoelastic definition may be interesting.
a
On Tue, Feb 21, 2012 at 7:52 AM, Robert Cimrman<cimr...@ntc.zcu.cz> wrote:
Hi Andre,
the new terms for evaluating fading memory stresses are implemented now, check [1]. It was a little bit tricky for the 'eth' version of terms because to compute stress one needs to know whole history of loading - there is no cut-off. Therefore 'preserve_caches' argument has been introduced to ProblemDefinition.evaluate() - it must be set to True to evaluate such terms correctly.
I have also changed the loading according to your suggestion. To get the time history plots, follow the instructions at [1] (or in the example docstring).
r.
[1] http://sfepy.org//doc-devel/****examples/linear_elasticity/**<http://sfepy.org//doc-devel/**examples/linear_elasticity/**> linear_viscoelastic.html<http:**//sfepy.org//doc-devel/** examples/linear_elasticity/**linear_viscoelastic.html<http://sfepy.org//doc-devel/examples/linear_elasticity/linear_viscoelastic.h...>
On 02/17/2012 06:50 PM, Andre Smit wrote:
Even better would be to remove the load after 10 steps, say, to see
delayed stress/strain recovery.
On Fri, Feb 17, 2012 at 9:37 AM, Andre Smit<freev...@gmail.com> wrote:
The stress/strain response of these materials are non-linear with time. I
suggest extending the example to show these responses with plots of stress vs. time and strain vs. time. Can the de_cauchy_strain/stress terms be used for this?
Andre
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