Energy & Mass error
Hi,
I am trying a snap fit in radioss,
I am facing the issue ' RUN KILLED : ENERGY ERROR LIMIT REACHED' and 'RUN KILLED : TOTAL MASS ERROR LIMIT REACHED'.
I checked for the Energy plot , I found steep rise in K.E just before termination.
Please guide me to resolve it.
out files attached for reference
Thank you
N.K
Answers
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Hi Karthic,
this error is common with inapropriate mass scaling, that is when you impose a time step which is too high. Check the mass error due to mass scaling in the .out file: in your model the mass scaling increases the system's mass by 57x. It is suggested to keep the overall mass increase bellow 2% and even then it has to be checked if mass is added to parts that are moving, which would increase the kinetic energy and therefore decrease the simulation accuracy. Short video for energy and timestep error
Alternatively you could try with advanced mass scaling (AMS) which does not add mass.
You can find more information from Introduction to Explicit Analysis using RADIOSS – A Study Guide in Time Step Control chapter. Also recommended is 2017 Radioss user guide starting from page 30.
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Hi @Ivan,
I have tried to keep the mass scaling below 2%, but still I am facing the same issue.
Please have a look at the out file attached.
<?xml version="1.0" encoding="UTF-8"?>
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Hi,
the reason could be that some elements get severely distorted which is causing excessive penetration. Since you are using hyperelastic material law you should try with hyperelastic property:
Try to increase the gap and use the following contact settings for type 7:
Istf=4
Igap=2
Fscale_Gap=0.8
INACTI=6
Gap_min=0.1
Fric = 0.1
Iform=2
Also, there is type 11 contact, which is actually causing the error. If it is defined on the same elements as type 7 then the gap should be 0.9x the value of type 7 and if using friction then also use Iform=2.
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