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dracu777

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About dracu777

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    Andorra
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  1. Hi guys, I share the solution with you in case anyone else had the same issue. My screen settings were set to 150% (see picture attached). FBD panel fully displays both with smaller and medium settings. Thank you for taking the time to help me out.
  2. Hello Sanjay, I tried but it's the same. I also tried to go through the options pressing the keyboard tab but at the end of the panel visualised, the selector moves to the visualization option. I am thinking to connect the laptop to another video to see if the problem is the screen size.
  3. Thank you Rahul, This is exactly what I was looking for!
  4. Hello Sanjay, Thank you for the reply. I tried to delete the file settings but it still doesn't work. Would it be possible to move the FBD window panel? In some CAD, like the model tree, it is possible to move it with the mouse to another position. I was thinking maybe, in that case, I can access the bottom by resizing it once free to move.
  5. Hi Prakash, I tried to move and fit the FBD area but It doesn't display the last part of that window. The version is HyperWorks Desktop 13.0.112 - June 2015 I don't know how to reduce the subcase area. I remember I had the same problem with Hyperworks 11.0 when I was following the training course in an Altair center but I don't remember how they made it work...I should have taken a note. Please, advice if you find a solution.
  6. Hi Rahul, Sorry, I saw your reply to my question only few days ago. I don't have the input file relating to the picture because I took it from a document. I would like to plot the eigenvectors, like in the picture above, using Optistruct (it would be great if it appeared in the .out file). I need the results only for "educational" purposes. If it wasn't possible I could obtain the same results using Hyperview, measuring the response of the modal analysis node by node, but honestly I hope there is a better way to do it.
  7. Hi all, I am testing the free body diagram functionality (FBD) but there is no way for me to display the all panel (see picture attached). Do you have any suggestions on how to do click the create button at the bottom of the page?
  8. Thank you Prakash, I will update you if I find a smarter way to calculate the preload.
  9. Thank you for the answer LKZ, yes it works like you said.
  10. Hi guys, I am reading the book "OptiStruct for Linear Dynamics" from Altair and trying to run direct and modal FRF analysis. If I apply a variable load all is good but I don't understand how to apply a variable displacement, velocity or acceleration. I defined the unit load as SPCD but I don't really understand the sentence on page 51 (see picture attached). It seems that I have to put a constraint on the node and direction that I want to excite. Can you help me?
  11. Hi all, I am exploring the Optistruct pretension manager capabilities instead of preloading the bolts in a "manual" way. Do you know if Optistruct iterates to find the right preload values starting from my input? Example: I need to apply a bolt preload of 20000N. Once applied, I calculate the sum of the gpforces on a section of the bolt and I find the total force to be 18000N. So I have to increase the input preload to 22000N to obtain an actual preload of 20000N. This is because of the elasticity of the components connected. Does Optistruct iterate starting from the input value to find the right preload value? As an additional question, is there a faster way in Hyperview to measure the gpforces on the section of the bolt? It is time-consuming exporting the value to excel to sum them all. Thank and Regards
  12. Hi Raul, Thank you for the answer. I can't dowload the .fem you uploaded (I don't know why) but I would like to do something like in the picture that I am attaching (I took it from an old Nastran output). I want to see if my hand calculations are right on a few dof system.
  13. Hi all, How can I plot the eigenvectors of a mass-spring system? I have a system like this: constraint ----spring-----mass-----spring-----mass-----spring-----constraint A 2 degrees of freedom system, in a modal analysis will output 2 eigenvectors. I would like to see the vectors in the output file along with the eigenvalues (it is only for educational purposes). How can I do it?
  14. Hi Prakash, There is a technique to evaluate the stress on a component at its natural frequency without running a frequency response analysis. Clearly, it is an approximation since it does not take into account the damping effect. I want to investigate what the error is in terms of percentage. In order to do so, I need evaluate the normal modes of the component (it can be done by running a modal analysis). For each natural frequency (eigenvalue) there is a modal shape associated (eigenvector). I need to apply as "displacement load" one of the modal shapes found in the modal analysis. The eigenvector that I need to apply to the part should be normalized to the largest displacement of the eigenvector. Namely, the largest nodal displacement should be 1 and the other displacements between 0 and 1. There are 2 things that I am not able to do yet: 1) save the modal shape for a natural frequency (NORM=MAX may normalize the vector the way I need) 2) apply the shape vector obtained in point 1 to the structure Sorry if I didn't make myself clear in the first post. I can also make a little presentation to explain it better.
  15. In few words I need to apply a static displacement to the nodes of the model. The displacement should be the normalized eigenvector a the first modal frequency. But I am still trying to understand how. The only thing that I have understood so far is that with RESVEC i can output the normalized eigenvector (see picture).
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