Transient analysis with longer duration
Hi,
This is very general query and asking this out of curiosity.
Assume there is a plastic part which is undergoing temperature variations for 7 hours of time. The part is heated for 1 hour and held for the same
Temperature for 2 hours. Then it is cooled to sub-zero temperature for 1 hour. Again it is held for the same temperature for 2 hours. Then it is brought to room temperature
for 1 hour.
To understand the structural behaviour of this part, how to proceed in FEA?
Is it a combined transient and creep analysis?
What are the material properties required apart from mechanical properties at elevated temperature and sub-zero temperature?
What kind of material model is required for this analysis?
Doing a transient analysis for 7 hours duration will lead enormous run time?
Pls throw some light on this?
Regards,
F Benjamin Franklin
Senior Manager
CAE - PD
Ashok Leyland Technical Centre
044-2539 8868
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I forgot to add a point here.
There are two long and slender plastic parts which have minimal gap between them. FEA is done to monitor the gap in all temperature ranges.
Is a Static analysis with some creep behaviour sufficient to do this task?
Reagrds,
Benjamin Franklin F
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Hi,
This is very general query and asking this out of curiosity.
Assume there is a plastic part which is undergoing temperature variations for 7 hours of time. The part is heated for 1 hour and held for the same Temperature for 2 hours. Then it is cooled to sub-zero temperature for 1 hour. Again it is held for the same temperature for 2 hours. Then it is brought to room temperature for 1 hour.
To understand the structural behaviour of this part, how to proceed in FEA?
Is it a combined transient and creep analysis?
What are the material properties required apart from mechanical properties at elevated temperature and sub-zero temperature?
What kind of material model is required for this analysis?
Doing a transient analysis for 7 hours duration will lead enormous run time?
Pls throw some light on this?
Regards,
F Benjamin Franklin
Senior Manager
CAE - PD
Ashok Leyland Technical Centre
044-2539 8868
[Description: Email_Signature]
The information contained in this communication is privileged, confidential and proprietary, and is intended for the sole use of/by the addressee. Usage by anyone other than the addressee is misuse and infringement to Proprietorship of Ashok Leyland Ltd. If you are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this email or any action or omission taken by you in reliance on it, is strictly prohibited and may be unlawful. If you have received this email in error, please contact the sender by reply mail and destroy all copies of the original message.
The information contained in this communication is privileged, confidential and proprietary, and is intended for the sole use of/by the addressee. Usage by anyone other than the addressee is misuse and infringement to Proprietorship of Ashok Leyland Ltd. If you are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this email or any action or omission taken by you in reliance on it, is strictly prohibited and may be unlawful. If you have received this email in error, please contact the sender by reply mail and destroy all copies of the original message.
Hi Benjamin,
This is similar to what we do in the thermo mechanical simulations of
electronic packaging. Where the loading in the form of thermal cycles with
certain ramp times for heating and cooling and dwell time for “holding” the
temperature at required levels. Our my main is the response of the solder
joints which are expected to deform plastically and creep (or
viscoplasitcity) is dominant.
From a recent experience, I had a structure with 50k elements. A nonlinear
material model (Anand Model) was incorporated and thermal cycle is 1 hour
long. The simulation was executed for 5 cycles using static analysis. The
ANSYS run time was around 2 hours and a half. I believe the simulation time
is driven by the number of elements (model size), number of solved
substeps, and the computer capabilities.
For the required material parameters, of course you will need to define the
elastic part of the stress-strain diagram. For the plastic part, this is
highly dependent on the expected behavior of your material. Is it creep?
Viscoplastic? Viscoelastic or something else? I would recommend that you do
some literature review before digging into it.
I hope this helps!
Best,
Mohammad
--
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Mohammad A Gharaibeh, Ph.D.
Associate Professor
Department of Mechanical Engineering
The Hashemite University
P.O. Box 330127
Zarqa, 13133, Jordan
Tel: +962 - 5 - 390 3333 Ext. 4771
Fax: +962 - 5 - 382 6348
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