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VABS-Input file format for recovery analysis

  1. Debaleena Chakraborty

    Can someone explain the Timoshenko format to be appended to the VABS input file to perform recovery analysis especially the last four lines( distributed forces and moments)? Also, the forces and applied at section level(F1, M1 etc.), are they applied or reaction forces/moments?

  2. Debaleena Chakraborty

    Any help on this aspect?

  3. Su Tian

    Hi,

    F and M are sectional resultant forces and moments calculated from the global analysis.

    f and m are distributed forces and moments, with primes indicating derivatives with respect to the beam axis.

    The VABS manual provides the complete input format for recovery. If you can provide more details about your question, I can help you better.

  4. Debaleena Chakraborty

    The displacements, u and the forces and moments, are they with respect to the same co-ordinate system, or are they extracted with respect to a local system each sectional position. Some sample recovery files would be of great help.

  5. Wenbin Yu

    I am not clear about your question. The displacement, force, moments are what you obtained from a beam analysis. They are with respect to the same coordinate system. ---- Emailed forum response from wenbinyu@purdue.edu

  6. Wenbin Yu

    Several data files contained in the VABS release are also able to be used for recovery. 

  7. Debaleena Chakraborty

    Thanks for helping me understand the recovery process. A pictorial description describing my doubts has been attached below for better understanding. Could you please help me further understand some doubts regarding the recovery analysis?

    VABS input format for recovery: pictorial description of doubts

  8. Wenbin Yu

    According to your picture, the values you used for recovery should be in the coordinate system which you computed your cross-sectional stiffness, which could be your cross-sectional coordinate system if you created the cross-section model using that coordinate system. ---- Emailed forum response from wenbinyu@purdue.edu

  9. Debaleena Chakraborty

    Thanks for your help and sorry for the late reply. About the C matrix, how do we get that? As per my understanding, it is the angle between the deformed and undeformed (each beam section, i.e pink section and green section in image) and evaluated at that local CS. Please help me understand if I am going about it the right way.

  10. Wenbin Yu

    Yes. However, if you are not interested in the 3D displacement distributions over the c/s, you can input it as an identity matrix because it is only used for computing the displacements, not the strains and stresses.  

  11. Debaleena Chakraborty

    Thank you. One more thing. How does one evaluate the distributed f, m? I mean, what we get from the 1D beam analysis are forces and moments and displacements at particular locations. How do we then estimate the distributed forces and moments?

  12. Wenbin Yu

    Those are the loads applied when you solve the 1D beam analysis. ---- Emailed forum response from wenbinyu@purdue.edu

  13. Debaleena Chakraborty

    Thanks for helping me understand the recovery format and going ahead with the process. 

    When VABS processes the recovery files, .ELE files are generated, which contains strains and stresses for each element at a section level. It seems there are two layers, at which the elemental strains and stresses are calculated, and that is how we end up with 25 columns in the .ELE files rather than 13. Could you please help me understand the format of these .ELE files? Is it a layer level calculation or something else?

  14. Debaleena Chakraborty

    Thanks for helping me understand the recovery format and going ahead with the process. 

    When VABS processes the recovery files, .ELE files are generated, which contains strains and stresses for each element at a section level. It seems there are two layers, at which the elemental strains and stresses are calculated, and that is how we end up with 25 columns in the .ELE files rather than 13. Could you please help me understand the format of these .ELE files? Is it a layer level calculation or something else?

  15. Su Tian

    Hi Debaleena,

    In the .ELE file,

    • column 1 is the element id,
    • columns 2-7 are strains in the beam coordinate system,
    • columns 8-13 are stresses in the beam coordinate system,
    • columns 14-19 are strains in the material system, and,
    • columns 20-25 are stresses in the material system.

  16. Wenbin Yu

    Debaleena, your question is unclear to us. Can you elaborate? ---- Emailed forum response from wenbinyu@purdue.edu

  17. Debaleena Chakraborty

    Sorry for the second question Sir. I am clear on my part now. Thanks.