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Ivan

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Ivan last won the day on January 16

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  1. Ivan

    Topographieoptimization - Beadfrac

    The idea of first performing optimization at the lower and upper bound of beadfrac parameter is to gain an understanding of the range of performance metrics you are trying to improve. In the following step (minimize beadfrac as objective) use the relevant performance metrics from upper/lower beadfrac optimization runs as constraints to formulate a reasonable/feasible optimization problem. The optimization to minimize beadfrac can be run with initial beadfrac=0, but you can also run with initial beadfrac at lower and upper bounds (-1 and 1) to evaluate if the design converged to local or global optimum.
  2. Ivan

    Plot Head Injury Criteria in Hypergraph

    Hi, you need to load the Vehicle Safety Tools preference file in HG (File > Load > select Vehicle Safety Tools > Load) Next, injury>HIC>Hic-Curve, chose the acceleration curve (shift+click) and set 36 ms windows length and finally clicked on apply.
  3. Ivan

    Element Orientation

    Hi, for material orientation review/edit use 2D>composites>material orientation panel. To assign nodes to a cylindrical coordinate system use analysis>system>assign panel. In the same panel, there is also an option for material orientation.
  4. Maybe the contact was not detected because shell thickness is smaller than the gap between solid and shell midsurface. Measure the gap (F4) and use Vicinity tolerance instead and provide a slightly increased gap. If other unwanted contact pairs are then detected consider creating the problematic contacts manually.
  5. Ivan

    How to remove intersection in solid elements

    Also try interface type 24: Try setting similar flags to type 7 crash recommended setup
  6. Ivan

    time step calculation

    Hi, the difference is because the characteristic element length is computed differently for shell and hexahedral elements: -Quad Shell: The square root of the shell area The critical length can vary with: • Shell formulation • Hourglass control parameters • Numerical damping • Membrane damping -8-node Hexahedral: Volume / largest face area I think the characteristic element length should be the same if element shape is close to ideal (square and cube), but could be different for distorted shapes.
  7. Ivan

    How to remove intersection in solid elements

    Hi, clearing intersection in this model should be easy- just translate one of the components in z-direction so there is a small gap, that is required for contact type 2 (tied) and 7 (general). If no physical gap is required then go for type 20 contact. Share the model if the issue persists.
  8. Glad to hear it is working. It's not working when the master/slave are swapped because nodes lying on the master surface can freely penetrate on slave surface. Interfaces are based on master / slave treatment. Contact can only occur between a set of slave nodes and a set of master segments. Master segments are defined depending on the type of element they lie on. If it is a 3-node or a 4-node shell, the segment is the surface of the element. If it is a solid element, the segment is defined as a face, Finally, if it is a 2D solid element (quad), the segment is a side. Check the following documents: https://insider.altairhyperworks.com/wp-content/uploads/2015/07/T-T-1119-OptiStruct-Defining-master-and-slave-roles-for-contact-surfaces-in-a-contact-pair.pdf http://blog.altair.co.kr/wp-content/uploads/2013/03/CONTACT_Card.pdf
  9. Ivan

    Topographieoptimization - Beadfrac

    Hi, the attached subchapter from Free eBook: Practical Aspects of Structural Optimization (A Study Guide) should be helpful. If the issue is not resolved share the .out file or the model. beadfrac.pdf
  10. Hi, choose the nodes on the edge as slave and use node to surface contact (DISCRET=N2S). Note however the contact surfaces of solid frame will only engage one node (at the corner of shell) when displaced in positive z-direction, because the shell mesh is so coarse only one node overlaps contact surface. Check the sample model with edge to surface contact. edge_contact.fem
  11. Ivan

    Displacement load

    Create a rigid body on impactor cylinder and then constrain its independent/master node in all DOF and apply the SPCD on the same node. Attached is the edited model. Check the modifications and compare to 3pt bend example. The analysis takes a lot of iterations to converge so perhaps there is a more efficient analysis setup. ESE in the global output request will output strain energy and strain energy density. steel_20kN_SPCD_edit1.hm steel_20kN_SPCD_edit1.h3d
  12. Ivan

    Displacement load

    Create rigid body using 1D>rigids. Boundary conditions are applied on the master/independent node. Output requests like displacements, forces,... can be requested by Analysis>output block.
  13. Ivan

    Changing hole location

    Hi, try with Geom>dimensioning However, for Hyperstudy parameterization Hypermorph should be used. Hypermorph is a really powerful tool, limited only by user's imagination
  14. Ivan

    Remaining time increasing.

    You're welcome! The following document could also be helpful (from Radioss Help) Interface Hints.pdf
  15. Ivan

    Bolt Pretension

    Hi, the best way is to use Pretension manager Pretension Manager - Altair University check the following examples and tutorials: OS-T: 1390 Pretentioned Bolt Analysis of an IC Engine Cylinder Head, Gasket and Engine Block System OS-E: 0015 Pretension Analysis using Gasket Material OS-E: 0140 Pretension Analysis of Piston
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