Difference between equivalent strain and total equivalent strain in modal analysis

- March 3, 2020 at 9:42 pm
  
  rajasekharbattu
  Subscriber
  
  I want the strain of the modal analysis and I don't know about these strains equivalent and total equivalent strains. In these two strains which strain gives values of (εxx,εyy, ?xy) values of each node like node1(εxx,εyy, ?xy),node2(εxx,εyy, ?xy)
- March 4, 2020 at 1:08 am
  
  peteroznewman
  Subscriber
  
  Relevant discussion.
- March 4, 2020 at 1:16 am
  
  rajasekharbattu
  Subscriber
  
  Hi Peter, can you please explain. I didn't understand the discussion
  
  Thank you
  Raja Sekhar
- March 4, 2020 at 2:04 am
  
  peteroznewman
  Subscriber
  
  Hi Raja,
  
  The relevant information from a Modal analysis is the frequency and the mode shape. Stress and Strain are irrelevant. Don't look at them in Modal.
- March 4, 2020 at 2:09 am
  
  rajasekharbattu
  Subscriber
  
  Hi Peter, thanks for your reply. I know that it is irrelevant but, I am working on reduction methods where I need strain data from modal analysis. To reduce the degrees of freedom in Matlab to use the data for some other work. If you know something about the modal strains in any analysis as the format I mentioned in the above post please let me know about that.
  Kind regards
  Raja Sekhar
- March 4, 2020 at 2:58 am
  
  peteroznewman
  Subscriber
  
  Does this mean that what you want is strain and not displacement, which you were asking for in this discussion?
- March 4, 2020 at 3:28 am
  
  rajasekharbattu
  Subscriber
  
  No Peter, that is another question. I don't want to mix the discussion. That discussion is for total deformation. Here my doubt about the strain data exported between equivalent strain and total equivalent strain
- March 5, 2020 at 8:41 pm
  
  peteroznewman
  Subscriber
  
  In a 3D model, the strain tensor has three normal strains and three shear strains.
  
  Are you asking about a 2D model? I ask because you don't mention the Z coordinate.
- March 5, 2020 at 9:23 pm
  
  rajasekharbattu
  Subscriber
  
  Yes you are right. But, my problem is I am in a need of strain tensor matrix for all nodes. I didn't mentioned the z because I want that data only. It is easy if I get whole tensor data of each node of the model in a txt file or as matrix. I can sort out the data which is needed from the matrix. When I am exporting the strain (equivalent vonmises or equivalent total) as txt file. The data contains only one value for node 1 and so on upto n nodes of model. I am struggling to extract all the different strains.