FRF direct/modal - variable acceleration

Altair Forum User

Hi guys,

 

I am reading the book 'OptiStruct for Linear Dynamics' from Altair and trying to run direct and modal FRF analysis.

If I apply a variable load all is good but I don't understand how to apply a variable displacement, velocity or acceleration. 

 

I defined the unit load as SPCD but I don't really understand the sentence on page 51 (see picture attached). It seems that I have to put a constraint on the node and direction that I want to excite. Can you help me?

 

 

 

 

Altair Forum User

@dracu777 

 

That means if you applied the displacement at the node for dof1 in type SPCD.

 

You need use the SPC to constraint the same node for dof1.