Jump to content

Ivan

Members
  • Content count

    56
  • Joined

  • Last visited

About Ivan

  • Rank
    Advanced User

Profile Information

  • Country
    Austria
  • Are you University user?
    Yes

Recent Profile Visitors

981 profile views
  1. Ivan

    tension only 1D element

    Hi, how to set up tension only (no compression, bending and torsion) 1D element in Radioss? I have tried with truss and spring elements. However, truss elements have axial compression stiffness and there is discrepancy in the plots, possibly because of geometric non-linearity. compression (truss in blue, spring in red color) tension spring_truss.hm
  2. Ivan

    Pin hinge and torsion spring

    Hi, thanks for the hint. How to model torsion spring (similar to Motionview): -Produces a moment between two bodies that is a function of the relative angular displacement and the relative angular velocity between the two bodies. -Free Angle specify the angular displacement produced when a torque is applied to the linear torsion spring.
  3. Ivan

    Pin hinge and torsion spring

    Hi, what is the procedure to define pin hinge with torsion spring in Radioss with similar functionality as in Motionsolve? In the file attached bellow I have modeled continuous pin (piano) hinge through type 2 contact with spotflag=4. This works great except there is no option to define small translational compliance (play in the hinge) or joint friction. The other option is to define the hinge through Kjoint2 spring, which requires rigid body on adjacent elements that adds artificial stiffness. How can torsion spring with rotational stiffness, damping, free angle and preload be added on pin joints? pin & torsion.hm
  4. Ivan

    fatal error #8004

    Hi, my observations is the same: this error only comes up when ESLM optimization is run with pattern repetition.
  5. Ivan

    fatal error #8004

    Hi, the optimization has stress constraint in DSIZE card. The same error happens when optimizing for minmax compliance subject to volume fraction constraint. ERROR _ 8004_minmax comliance.hm
  6. Ivan

    fatal error #8004

    Hi, the same error # 8004 occured when free-size ESL optimization is run with pattern repetition. Error termination happens after first outer loop, just after updated master CMS flex file is generated. The message from out file is: ERROR # 8004.hm
  7. Hi, what is the procedure to transfer MBD models created in Hypermesh to Motionview and vice versa?
  8. Ivan

    Polar array system/assembly

    Hi, sorry for the inconvenience. Please find the requested files attached bellow. I am using version 2017.2. Is there a way to orient & position flexible bodies? Regards, Ivan polar_graphic.h3d polar.fem
  9. Ivan

    Polar array system/assembly

    Hi Praful, thanks for your response. The described approach only seems to works for primitive graphic entities and is not applicable to the model I have shared (containing imported CAD graphics). As a workaround, on import CAD dialogue there is a Locator points option to later position, orient and scale CAD graphics in Location tab on the graphics panel. The main drawback with this approach is it can only locate one graphic at a time so it can not be used efficiently for systems/assemblies.
  10. Hi, I need help modeling polar array (rotational symmetry) using system/assembly. When instancing the sub-systems they stay at their original position and orientation. There is an option System translation, but no rotation. The 4 sectors needs to be attached to central polygon as well as to adjacent sector. Is there a way to automatically align subsystems with attachments? polar_array.mdl SECTOR.mdl
  11. Ivan

    rigid body mechanism

    Hi George, thanks for the tip. I will try to simulate with flexible body in Motionsolve.
  12. Ivan

    rigid body mechanism

    Hi, Is it possible to simulate a rigid body mechanism similar to rigid MBD? Bodies and joints have to be perfectly rigid to avoid jamming/binding closed kinematic chain mechanisms. Attached is the sample containing RBODY elements connected through revolute Kjoint2, which is defined with stiffness so there is some unwanted compliance. Any ideas or workarounds to carry out kinematic studies in Radioss? rigid_body_mechanism.hm
  13. Ivan

    Multi point Constraint

    Thank you for the tip, however I am unable to properly apply this workaround. The reason is this model probably needs node to node constraints like MPC. Could you please look into the files?
  14. Ivan

    Multi point Constraint

    Hi, I would also like to know how to create MPC in Radioss user profile to model cyclic symmetry. An example using this type of kinematic constraint would be appreciated.
  15. Hi George, I have tried with Isolid=17, which eliminates horglassing, but the run stil terminates with negative volume. There is also the problem with contact type 3 stiffness between soft (rubber) and hard (wood) parts. Attached are excerpts form Radioss User Guide 2017 which discusses such situations. To get the stiffnes ratio of hard over soft material the Young's or bulk modulus is required, but I only have ogden material parameters. I have also unsuccessfully tried type 5 interface with arbitrary contact stiffness scale factor of 170. planestrain_hinge_convolute.hm
×