Learning Forum

[Audy Maulizar]

Dear all. I want to ask if it is possible to assign a VIV wind load on a bridge deck that varies with velocity and displacement of a node. The load is defined by the following function according to model by Scanlan. 

The nodal loads are applied on the bridge deck as follows. 

The y and y_dot are bridge deck displacement and bridge deck velocity respectively. The load for a time step will change based on the value of deck displacement and deck velocity from the previous time step. I wonder if it is possible to program this routine in ANSYS Mechanical or LS-Dyna?

 

[Erik Kostson]

 

 

Hi

Normally for VIV one would use in Ansys tools 2 way FSI (Fluent and Transient).

 

We do not have anything for this, but have a subroutine (you would need to code it) called USRCAL that could be perhaps be used without knowing the details (as we do not have anything specific for viv and associated loads).

 

LS-Dyna has smilar and easier to use *Define_curve_function keyword, or *define function that could be used here perhaps. See the keyword manual Vol I of LS-Dyna.

 

So all the above describe ways to define loads that depend say on the current or previous velocity of a node etc.

All the best

 

Erik