Dear RG members,
I'm carrying dynamic analysis on retaining walls using UDEC software (DEM).
I'm asking myself what kind of damping should be used (Rayleigh damping, local damping, no damping) for my analysis.
In fact, it seems that Rayleigh damping is more appropriate for dynamic analysis. However, on an identical model, changing the damping (from no damping to rayleigh damping or from local damping to rayleigh damping) led to an decrease of the timestep from 1e-5 to 1e-7 (depending on the values (freq, damping) chosen for the rayleigh damping). This new value of timestep make the simulations hundred times longer which is not satisfactory.
Do you have any ideas to deal with this problem? Do you know why the timestep is decreasing?
I've read the UDEC manual and the described methodology to compute the timestep in dynamic analysis, but it does not match the values given by UDEC.
Thank you !
Nathanaël
Thank you Chitaranjan Pany,
I won't put too many damping in my dynamic analysis.
What kind of damping (rayleigh, local, other) do you suggest ?
What influence does it have on the timestep ?
Ok, many thanks,
then it's the rayleigh damping (viscous and mass damping) in my case.
Ok thank you for this point.
Do someone have an idea on explaining why, when i'm using rayleigh damping the timestep is becoming incredibly low (1e-10), so that it's making the simulations too long.
Indeed, adding a rayleigh damping make the timestep lower but not at the level observed in my cases. Do you have any ideas to explain it ?
Thanks a lot,
Nathanaël
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