Stiffness calculation

[Arul 3]

Is it possible to calculate the Stiffness (N/m or N/mm) of the structure from any analysis??

[Q.Nguyen-Dai 293]

Yes, it's possible. Apply a force and compute the displacement.

So :

stiffness = force / displacement

 

[Rahul R 316]

Are you looking for Global Stiffness Matrix Output? If so then  use the DMIG approach to generate stiffness matrix for the entire model. 

[Arul 3]

Hi Rahul ,

 

Not Global stiffness matrix. I am looking for stiffness value as output (like Stress, Strain,Displacement). Is there any other way to find out by analysis?

[Rahul R 316]

This information should be written in the .out file of Optistruct Run for different types of analysis.Normally we call this as OUTPUT in loadsteps or Global output request under control cards.(Stress, Strain,Displacement)

[Arul 3]

Hi,

 

Is it possible to extract stiffness value  ( instead of Global stiffness matrix using DMIG)  ?

[Guest]

Hi Arul,

 

If you are looking or stress, dispalcement, strain etc.. in ASCII format, Yes, it is possible.

 

goto Control cards>> Global Output Request>> Stress>> change output format to Opti/OUTPUT. Similarly do the same for Strain, displacement, etc... based on your requirement.

 

If you want to output STIFFNESS (other than global stiffness matrix), no it is not possible. Compliance will be written in .out file, though.

[Arul 3]

Hi ,

 

Thanks for your reply.  How to write Compliance?

[Guest]

Arul,

 

Compliance will be written in the out file by default for each subcase.

 

Search for compliance in .out file.