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Hallo Group
I want to have value of frequency response function Mobility defined as (Normal velocity/ force) at some points on my structure.
I am doing direct frequency response analysis with optistruct. How do I go about it.
Regards
Pratik
Hi Pratik,
Please refer to Frequency response function tutorial on our help documents.
OS-1300: Direct Frequency Response Analysis of a Flat Plate
OS-1305: Modal Frequency Response Analysis of a Flat Plate
In addition refer to RLOAD2 card (used in above mentioned tutorials) to learn how to apply velocity as a freq function.
Step 8: Create a Set of Frequencies to be used in the Response Solution
can you elaborate this steps? does is it calculate the response for only this 49 freqencies (20 hz -1000 hz)
Modal frequency response : does it used some Modal matrix reduction method? any literature for optistruct about this method?
Can i use EIGRA instead to EIGRL for Mode frequency extraction
Yes, response is calculated from 20-1000Hz.
You can use EIGRA for modal FRA. You can refer to OptiStruct user guide form more information on FRF analysis.
Altair OptiStruct > User's Guide > Structural Finite Element Analysis > Solution Sequences:
Hello Prakash
In Step 5: Create a Unit Load at a Point on the Flat Plate
7 Uncheck all the dof's; except dof3, and click the = to the right of dof3 and enter a value of 20.
what dies the value 20 stand for? Isn,t it unit load?
Pratik,
that is the load/exitation you are giving in Z-direction.
If you are giving load type as enforced displacement for instance, then the node will be displaced by 20 units.
so what exactly is Modal Frequency Response , how does it differ from drect frequency response
for example If i want velocity response between excitation frequency between say 1000 to 2000 hz , but i want response only at eigen frequncies in this range should i do Modal Frequency response analysis?
OptiStruct > User's Guide > Structural Analysis:
Hello Group ,
I want to have value of frequency response function Impedance defined as (Acceleration / force) at some points on my structure. I am doing modal frequency response analysis with optistruct. How do I go about it
Also Suggest Control Cards and other inputs
