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Everything posted by Hyperman

  1. Hi, there are a number of ways to find master node ID:
  2. 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
  3. 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.
  4. 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
  5. 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
  6. 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
  7. 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.
  8. 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.
  9. 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
  10. 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
  11. Hi, To define a membrane, please leave MID2 and MID3 blank on the PSHELL property, or use PARAM,SHL2MEM.
  12. Hi, this error was already posted: Which version are you using? Can you share the model?
  13. Hi, use Analysis>pressures>linear interpolation. More details: https://insider.altairhyperworks.com/wp-content/uploads/2018/02/T-T-1291-AcuSolve-Map-Pressure-to-a-Structural-Solver.pdf
  14. Hi, only linear elastic composite material models (MAT8, MAT9, MAT9OR) are available in Optistruct. Altair Multiscale Designer does support nonlinear composite materials.
  15. Hi, there are many techniques to connect shell and solid elements: -using rigid elements -inserting a layer of shell elements inside solid elements -inserting a layer of shell elements on the face of solid elements shell2solid.fem
  16. Glad to help. Refer to the attached document for contact interface types and their applications. RADIOSS_for_Impact_Analysis_v14.0.pdf
  17. Hi, the negative energy error can be considered acceptable in this case due to sliding contact with friction and the energy is transferred through the contact interface. As the contact energy is increasing at a slower pace than the total energy (plots are diverging) the energy error percentage will reduce throughout the simulation. Only type 7 contact interface can be used since there is no edge penetration issue.
  18. Hi, Points are one of the fundamental construction elements for multibody models built in MotionView. Also, almost all the entities that can be created in MotionView need to use points either for defining their location or orientation. Therefore the creation of points is an important task in model building within MotionView. Points.pdf
  19. Hi, Large contact energies relative to total energy can cause large negative Energy Errors because contact energy is not part of the Energy Error equation. If the simulation has friction and a lot of sliding contact, then the large contact energy and resulting energy error can be considered acceptable. example-edit_0000.rad
  20. Hi, Use the recommended contact parameters for interface Type 7: Istf=4 Igap=2 Fscale_Gap=0.8 INACTI=6 Gap_min=1 Fric = 0.1 Iform=2 Another reason for timestep drop and energy error is because Interface type 7 does not deal with edge to edge impact. When the mesh is fine enough, edge to edge penetration is often followed by a node to shell contact. The main problem with edge to edge impact is the locking situations. If there is a change of load after edge penetration, locking is unavoidable since a node to surface contact is detected. This usually leads to high penetration; therefore, the analysis comes to a standstill as time step is reduced. If locking occurs, the use of interface type 11 in this area is necessary to solve the problem. Share the model file if the issue persists.
  21. Hi, negative energy error represents energy dissipated from the system and this can be from many sources like plastic deformation, hourglass energy, contact with friction, damping,... Review the energy balance to identify the source of this error. Since the energy error is high in combination with timestep drop (remaining time increasing) my guess is hourglass issue. Use Isolid/Ishell=12 or 24 and try running the simulation. Check the out file for warnings and errors. In this case the error 1109 is because no variable is defined for output request. The default output requests are defined by entering DEF in the Data: Var table.
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