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STAAD Time History using Primary and Secondary Unbalance Load

STAAD Time History using Primary and Secondary Unbalance Load

STAAD Time History using Primary and Secondary Unbalance Load

(OP)
Good day to ALL:

I would like to ask for advise on INPUT in Time History Analysis using STAAD.
I have a vendor data which which states PRIMARY and SECONDARY unbalanced loads/couples for the given Compressor. I'm familiar with Time History Analysis for ROTATING MACHINES (which has 1 Unbalanced Input only), but for CENTRIFUGAL MACHINES like compressors, Primary and Secondary Foces and Couples are given.

Here it goes:
1) Machine Speed
Primary 10Hz
Secondary 20Hz
2) Unbalanced Load:
Primary (vertical) 1000 kN Phase 150 deg
Secondary (Vertical) 10 kN Phase 0 deg
3) Time Duration = say 2.0sec

From Above unbalanced loading, I have the following Time History Input:

DEFINE TIME HISTORY
TYPE 1 FORCE
FUNCTION SINE
AMPLITUDE 1000 FREQUENCY 10 PHASE 150 CYCLES 20 STEP 0.0083
FUNCTION SINE
AMPLITUDE 10 FREQUENCY 20 PHASE 0 CYCLES 40 STEP 0.0042

I consider only 1 Type since both functions will act on same node.
CYCLES = Time Duration / Period
STEP = Period x (1/12), where 1/12 is the STAAD recommendation (default)

Are my input correct? Or did i overlooked something?

Regards.


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