question on using viscous material with zero length element

Lanka · Post by **Lanka** » Tue Feb 26, 2008 9:09 am

Hi Silvia,

I am trying to use viscous material with zero length to represent a damper. I understand from the manual, viscous material can be used to used to construct a uniaxial material object with a non-linear elastic stress-strain-rate relation given by:

stress =C(strain-rate)^alpha.

My question is- With a zero length element, can I use the same material to construct a Force-deformation-rate (i.e force-velocity) relation given by:

Force=C(velocity)^alpha

Thanks.

-Lanka.

silvia · Post by **silvia** » Tue Feb 26, 2008 10:35 am

Yes, you should be able to.

Lanka · Post by **Lanka** » Tue Feb 26, 2008 11:29 am

Thanks,

I calculate C as a factor of critical damping (C= damping ratio*critical damping) to use in the second relationship. The unit of C in second case is kg/s , which is different from that of first case (kg/s/m).

How the "C" (i.e tangent) values are related between two relationships? How to specify C when I use this material with a zero length element? Is that Ok to use calculated C from second case , when I use this viscous material with a zero length element?

Thanks