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Everything posted by Hyperman

  1. Hi, you are not getting the animation output because the simulation runs so slow it does not even reach the animation output interval defined. The reason simulation runs so slow is because of the low timestep which is 1.3e-7 ms, while the usual timestep is on the order or 1e-3 ms. The timestep is related to the Size of the smallest element (characteristic length) and Sound propagation speed (stiffness and density). While you can not change the material properties, you can remesh with larger element size and apply timestep control. For more details see the attached document from free Radioss ebook: timestep.pdf 3_Timestep - Altair
  2. You're welcome. No animation is output because the simulation ends at 3e-3 which is far less than TFREQ=1. 20-50 animation frames are usually output so TFREQ should be /RUN/Tstop divided by 20-50.
  3. Hi, you have shared the starter file which does not contain simulation controls. Use Tools>engine file assistant to set up the simulation controls. Define animation output frequency ANIM/DT to get the animation output.
  4. Hi, imposed velocity (and other boundary conditions) can not be defined by a vector. It can be defined in a global coordinate system (by default) or a local coordinate system (skew). The procedure to create a skew (from 25:00:
  5. The increment can be fixed using either: DTmax=DTmin PARAM>EXPERTNL>NO However NLADAPT>DIRECT>YES does not work for some reason.
  6. Hi, Increment adjustment is automatic by default PARAM>EXPERTNL>AUTO. Try with PARAM>EXPERTNL>NO instead.
  7. Hi, -you have created rigid with the master node on a structural element- this is not allowed. Make sure you use the "calculate node" or pick a free node (not connected to other elements) as independent node when creating rigid elements. Set Icog=3 or 4 so the master node will not be moved to CG -check unit consistency: the material properties are in tonne, mm, s so the gravity should be 9810. Also, define appropriate units in the begin card -gravity was acting in the wrong direction, so a negative scale factor was applied to reverse the direction -the boundary condition on the tilted platform constrained 1236 DOF. It should constrain 12345 instead -the contact sets between wheels and tilting platform were swapped -advanced mass scaling AMS is used instead of DT/NODA/CST mass scaling -the run time was extended to allow the bus to hit the ground -the floor is not large enough: rigid wall can be used as ground instead simple_bus_7_edited.hm
  8. Hi, looks like the plyxfem functionality is still in beta version so it can only be set up manually with text editor. from Radioss help: plyxfem_0000.rad
  9. Hi, Use Tools>Model Checker>RadiossBlock to find modeling errors. https://insider.altairhyperworks.com/wp-content/uploads/2017/09/T-T-1248-HyperMesh-Model-Checker.pdf Review the starter out file for errors and warnings. The following modeling errors were found: No card image and material were defined for the "PLYdown" component the SHELL GROUP ID : 1 was empty INPUT ERROR IN MATERIAL LAW 25: no material properties were defined in SIG fields the imposed displacement load collector was referencing an empty group of nodes prova_radioss_edit.hm
  10. Hi, here is the Procedure to apply Initial_velocity around an axis 9- Procedure to apply Initial_velocity around an axis - Altair University Also, make sure to constrain de independent node of a rigid body in all other degrees of freedom. Share the model if the issue persists.
  11. Hi, there are a number of ways to find master node ID:
  12. Hi, you can use pin a / pin b of beams to specify the degrees of freedom which are not intended to transmit force. For more details refer to: https://altairuniversity.com/wp-content/uploads/2017/03/1D_Elements_Extract.pdf
  13. Hi, If you want to explore attaching hat sections stiffenerse then the mesh used is way too coarse. At least 3 elements through-thickness of sheet metal stiffener are required as optimization results are mesh denendant. Consider using a single draw>stamp manufacturing constraint.
  14. Hi, I am able to download on my end. userlaws-dll.pdf You may also find the following useful: https://www.altairuniversity.com/wp-content/uploads/2012/08/radioss_user_code_interface_jun_2012.pdf
  15. Hi, Use Tools>Model Checker>RadiossBlock to find modeling errors. https://insider.altairhyperworks.com/wp-content/uploads/2017/09/T-T-1248-HyperMesh-Model-Checker.pdf There are solid as well as shell elements at the core of the sphere in the same component collector as the plate shell elements- this is invalid. Move the solid elements into another component referencing a solid element property. This will also resolve initial penetrations. In case of penetrations use the tools>penetration check. The velocity and Sphere SPC load collector should refer to the master node of a rigid element. the shell property is modified advanced mass scaling is applied Test-edit_0000.rad
  16. In the model you shared the optimization problem was actually min volume fraction with a constrained frequency of the first mode. The objective and constraint should be switched as you proposed (min 1st frequency s.t. 0.5 VF). To make sense of topology optimization results it is useful to output ESE- strain energy. I have reduced the order of tetra elements and meshed the design space with hexahedral elements to save computation time. Note however the model is stiffer due to 1st order tetra- the plate should be structured hexahedral meshed for accuracy and efficiency. The minimum and maximum member size were used on topology>parameters. Door_opt_Topo_Opt-edit1.hm Refer to a similar example OS-E: 3005 Eigenvalue Maximization for alternative approaches (topography + multi frequency optimization setup). OS-E_ 3005 Eigenvalue Maximization.pdf eigenplate.fem
  17. Glad to help. 1. Yes. 2. In ply based modeling the resin and fiber material properties are usually homogenized on a ply level. Multiscale Designer can be used to model the composite behaviour at the constituent scale.
  18. Hi, bolt pretension is also supported for linear static analysis however, no such tutorials are available. It is possible to perform sequential linear and nonlinear static analysis with bolt pretension.
  19. Hi, always review the out file for warnings and errors: Use Tools>model checker>Optistruct to find modeling errors & warnings and apply autocorrection. Or use Check Elems Panel (F10)>1D>free 1d nodes. https://insider.altairhyperworks.com/wp-content/uploads/2017/09/T-T-1248-HyperMesh-Model-Checker.pdf Tp desenho casca-edit.hm
  20. Hi, refer to tutorial OS-T: 1390 Pretensioned Bolt Analysis of an IC Engine Cylinder Head, Gasket and Engine Block System. Pretension.hm OS-T__1390_Pretensioned_Bolt_Analysis_of_an_IC_Engine_Cylinder_Head,_Gasket_and_Engine_Block_System.pdf
  21. Hi, To define a membrane, please leave MID2 and MID3 blank on the PSHELL property, or use PARAM,SHL2MEM.
  22. Hi, this error was already posted: Which version are you using? Can you share the model?
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