I am trying dynamic design of structure for rotary machine in staad with the help of Time history analysis command.
The shaft of the machine is parallel to vertical axis & is mounted on structure over 2 base plates.
So i have defined TH command Type 1 force(sine function) & Type 2 force(cosine function) for Z & X direction.
Then i have assigned both forces in single load case for FZ & FX direction at same arrival time.
All parameters for TH Type 1 & Type 2 are same
Question:
1) Is above procedure right?
2) In case of seismic analysis, we have to assign inertial masses (self weight, joint load,member load in X Y Z directions) in dynamic(TH) load case.
Do we have to follow the same procedure with machine vibrations defined as FORCE in TH command definition? If yes then Why?
3) I have considered 2 cases for analysis.
Case 1:Type 1 force (sine) in FZ direction &Type 2 force (cosine) in FX direction
Case 2:Type 1 force (sine) in FX direction &Type 2 force (cosine) in FZ direction
For both cases post processing results were different? But this should not happen i think .
Bec what i read from another post from community that for TH, staad only consider maximum values of forces.
Please give suggestions.
Any reply will be appreciated.
Thanks.