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Tiago

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Everything posted by Tiago

  1. try to mesh the surface on HyperMesh and when it is ok you import into AcuConsole. Is it failing in the surface mesh creation or in the boundary layer generation?
  2. Thank you. I managed to figure it all out. Now I am having a bit of trouble with the residuals that don't want to drop below 1e-02 but the forces are reaching an almost constant value so I think its converging.
  3. Hey guys, I have been using Acusolve to make a cfd analysis on a car. I am using SST for the turbulence equation without a transition model and have been working great. I wanted to use Gamma Re theta to see if the results get more or less accurate but I get an error when I try to use it. acuSolve: *** ASSERTION in Function <lesGmres> File <lesGmres.c> Line <1379> acuSolve: *** Error from fLesGetHbrgEig <40> acuRun: *** ERROR: error occurred executing acuSolve" What can this be guys? thank you in andvance!
  4. Hi guys, I have been performing an analysis in Acusolve and wanted to see an animation of the points but I cant click on the option Transient Data as the tutorial suggests. When I click build on the seeding panel, the points only appear one time in all the time steps and I cant visualize them moving. The global problem solution was defines as transient using SST and fixed mesh. Also I need to get the drag. How should I get the values to calculate drag or Lift after performing any Steady State or Transient analysis? Thanks in advance
  5. Hi George, I managed to low the simulation time. The quasi-static test is working. Thanks a lot for your advice and help.
  6. And what if I use a higher velocity? will the results be substantially different from a low velocity compression test?
  7. Hi George, Where can I find those documents? And thanks again for the help.
  8. I spotted an error in the material model. Corrected it and radioss runs now, the problem is that with a time step of 1ms, the mass error is getting to 5e+6. With this time step the calculation requires 2000 seconds to run. If i use an even smaller time step will raise the time to many hours or even more than a day Using a time step of 0.1 ms and reducing the time of the test i could get the calculation process down to 6000s but the mass error is still 1e+4
  9. I have seen many times explained that the time step must be in the order of the time that a sound wave takes to cross an element. In explicit dynamic analysis that works because the crash tests takes about 100 ms to occur. A quasi static test with a speed of 2mm per second takes more than 1 minute so the same time step traduces on a computation time of 14 days. If I try to impose a minimum time step of around 0.1s it is ignored and a time step of 9e-4 is used by radioss. I don't know why. And even if i can impose it, will it be accurate? There's any way to make it implicit so we don't have to worry with the time step? or can radioss perform it as explicit with a high time step and still have accuracy? Adding a control card DT_ELTYPE_KEYWORD_IFLAG it runs for a bigger time step but the error is getting to -95% since the start
  10. Ok I sent via dropbox. Can you check it please?
  11. Yes, i did that but the command is ignored.
  12. the speed must be in the order of 1 or 2 mm per second so the time step must be closer to 0.1s
  13. Hi George, The quasi static analysis must consist in a simulation of a compression test of a structure so I will impose a velocity in the end nodes of the structure and crush it onto a rigid wall. I increased the time step to 0.1 s but since the beginning of the calculation, radioss is using a time step of 9e-4 what makes the expected time raise to close to 300 hours. How can I impose the time step? I am using DT1 and DTIX control cards to impose minimum maximum and initial time step
  14. Hello, I have completed a dynamic crash analysis on hypercrash and wanted to convert it to quasi-static. The dynamic analysis lasts no longer than 100 ms so I can use a low time-step. How should I proceed to be able to use radioss for a 2 minute simulation with a higher time step? Is is possible with explicit analysis in radioss or should I use another software? I changed the velocity to an imposed velocity and I am using no mass in order to make it quasi static. The minimum time step that I am introducing is being ignored when the calculation software starts. Any advice? Thanks in advance.
  15. The connectivity is ok and the rigid body too. I followed that tutorial and I am making a new simulation now but it takes 10 times more time than the old one to run. I am trying to use the exact same material and connections to see if the problem has another source. For that kind of steel and an element characteristic length of 5mm i am using an inicial timestep of 5 as they recommend. But in my calculations it should be closer to 1 if I am not mistaken. It will take an hour to run. I let you know if its working.
  16. Hello, I am making a setup of a simple bumper structure colliding with a rigid wall on HyperCrash. I am using the Johnson-Cook model for the material. The structure is made of a beam with 2 crash boxes attached with spot welds. In the beginning of the test the structure is already vibrating (Capture2) and seems that the boxes are colliding with the beam instead of being attached. Can anyone help me to solve this vibration problem? can it be from the type of connection that I am using? Should I use other? see the print screens and tell me what you think. There are stress concentration close to the spot welds because they are completely rigid elements (Capture3) Another big problem is that the material is not having the desirable behavior. It is aluminum and should bend on crash but is not bending, its fracturing (Capture4)
  17. I have been 3 days with this problem... Thanks a lot. RADIOSS is running. I let you know if I have good results
  18. I have seen other posts with this problem and I have tried to assign card image but I dont know how to do it in HyperCrash
  19. I have done all of that and im having this problems: ERROR ID : 194 ** ERROR IN HIERARCHY REFERENCE DESCRIPTION : -- NODE GROUP ID : 4 -- INIVEL_group_4_of_PART TITLE : PART REFERENCE TO UNEXISTING ID=7 WARNING ID : 690 ** WARNING IN NODE GROUP DEFINITION .. INITIAL VELOCITIES .. DOMAIN DECOMPOSITION .. ELEMENT GROUPS .. INTERFACES ** ERROR TRAPPED : REPORT TO LISTING FILE ERROR ID : 760
  20. I think I am having the same problem. But in this version (12) I cant find the way to assign part image. Cant find the export options. This appears:
  21. Im having the exact same problem. How do i check the hierarchy? there's a strange image in my parts in the browser tree, maybe its because of that but I don't know how to solve it . The errors are these: ERROR ID : 194 ** ERROR IN HIERARCHY REFERENCE DESCRIPTION : -- NODE GROUP ID : 4 -- INIVEL_group_4_of_PART TITLE : PART REFERENCE TO UNEXISTING ID=6 ** ERROR TRAPPED : REPORT TO LISTING FILE ERROR ID : 760 WARNING ID : 690 ** WARNING IN NODE GROUP DEFINITION .. INITIAL VELOCITIES .. DOMAIN DECOMPOSITION .. ELEMENT GROUPS .. INTERFACES
  22. Hello, I am trying to setup a crash of a bumper geometry. The bumper consists in 1 curved beam and 2 crash boxes. I used contact interface type 7 but I am having some errors. ERROR ID : 59 ** ERROR IN PROPERTY/ELEMENT DEFINITION (NUMBER) DESCRIPTION : INVALID PROPERTY ID=0, FOR SHELL ELEMENT ID=2553 ERROR ID : 61 ** ERROR IN MATERIAL/ELEMENT DEFINITION (NUMBER) DESCRIPTION : INVALID MATERIAL ID=0 FOR SHELL ELEMENT ID=2554 ** ERROR TRAPPED : REPORT TO LISTING FILE ERROR ID : 760 ERROR ID : 194 ** ERROR IN HIERARCHY REFERENCE DESCRIPTION : -- SURFACE ID : 7 -- INTER_group_8_of_PART TITLE : PART REFERENCE TO UNEXISTING ID=6 ERROR ID : 119 ** ERROR IN INTERFACE SURFACE DEFINITION DESCRIPTION : -- INTERFACE ID : 1 -- INTERFACE TITLE : New INTER 1 MASTER SURFACE IS EMPTY WARNING ID : 692 ** WARNING IN SURFACE DEFINITION Some of them refer material/proprety problems but I am sure that my material and property are well defined. On top of that I have this image for the parts and I don't know why. (see attachment)
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