Hi,
I have modelled a cantilever beam without assigning ant damping to the model. Yet, I accelerations response is damped. It seems there is a default damping ratio was assigned by the software itself. Do you know how can I find this ratio?
Thanks
Perhaps your frequency range is just too limited (if you are doing a frequency sweep). If so, try increasing around the resonance and hit many frequencies around there.
About numerical damping in Abaqus/Explicit look at 9.5.1 Bulk viscosity: http://wufengyun.com/v6.14/books/gsa/default.htm
Dear Mohammad,
you can use Rayleigh damping. for this first you should frequency analysis then determine Rayleigh coeffecients.
https://classes.engineering.wustl.edu/2009/spring/mase5513/abaqus/docs/v6.6/books/usb/default.htm?startat=pt05ch20s01abm43.html
By default, Abaqus does not assign any damping. You should consider increasing the resolution, the response would tend to infinity
Hello Dear Mohammad,
What kind of analysis you performed? Is it implicit dynamic analysis? If yes, then abaqus bydefault considers a certain amount of numerical damping in the dynamic analysis because implicit method in abaqus is based on Hilber-Hughes-Taylor operator involving alpha, beta and gamma factors in which alpha factor plays a role of numerical damping. On the other hand, Newmark family methods involve only beta and gamma factors with no consideration of numerical damping. If you put alpha=0 in the implicit step module then you can avoid an unwanted numerical damping in your analysis. Hope it will help you somehow.
Best,
Khawaja Ali
Abaqus does not assign any default damping but depending upon your problem, you can easily define the damping ratio.
Dear Khawaja Ali
What about default damping in Abaqus Explicit? If Rayleigh damping is not introduced, then how does the software introduce damping?