Stiffness calculation

Arul

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

Q.Nguyen-Dai

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

So :

stiffness = force / displacement

 

Rahul Rajan_21763

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

Arul

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 Rajan_21763

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

Hi,

 

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

Altair Forum User

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

Hi ,

 

Thanks for your reply.  How to write Compliance?

Altair Forum User

Arul,

 

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

 

Search for compliance in .out file.

<?xml version="1.0" encoding="UTF-8"?>