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Simon Križnik

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  1. Thanks for your response. Hopefully, NLFE will be supported in a future version of HM. As a workaround, is it possible to append Motionsolve xml commands with BULK or CASE_UNSUPPORTED_CARDS?
  2. Hi, can Non Linear Finite Elements (based on Absolute Nodal Coordinate Formulation or ANCF) be created with Hypermesh preprocessor?
  3. Hi, actually only one SPRING2N element is created; the other two elements on either end of spring are plot elements (1D elements with 2 nodes used for display purposes only). Use proper post script to realize connectors upon creation. Otherwise use the realize subpanel.
  4. Without the model file, my best guess is the contact at the edges are not detected. If that is the case, define an additional type 11 or 19 contact. You may find helpful Free eBook: Introduction to Explicit Analysis with Altair RADIOSS. I have recently revised the third edition which should be available in the near future.
  5. You need to define local skew and Def_orth=1 only for those plies that have an invalid orientation assigned by /STACK (in your case Vx=1, Vy=0, Vz=0 means only plies whose normal points in global x-direction has to be corrected). All elements with PCOMPP prop_ID type must belong to a ply (/PLY) inside a stack (/STACK). CarbonBox_edit_0000.rad
  6. The first anisotropic direction of material could be defined with angle ϕ and global vector (Vx ,Vy ,Vz ). It is also possible to use angle ϕ and skew. In this case, x-axis of skew replaced the global vector V. The orthotropy direction is set with Vx, Vy and Vz parameters in /STACK card (laminate). To override laminate direction set up ply with local skew and Def_orth=1. CarbonBox_edit_0000.rad
  7. Hi, when assigning material orientation, make sure the direction is not perpendicular to shell elements. You have probably assigned material orientation in the height direction for the whole component, which is invalid for the elements on top (check material orientation of element 1600). The best practice is to assign material orientation for each surface one by one.
  8. Welcome, refer to step 8: https://connect.altair.com/CP/SA/training/self_paced/aero_v13/PDF/chapter10_demonstration.pdf
  9. Upon looking into the model again I found the reason why the buckling initiates at the base of upper crashbox. Looking at the cross-section (deformation scaled 5x) it is revealed the clamping region at the base of upper crashbox slightly rotates inwards, which initiates the buckling. The reason for this behavior is the primary load paths are not aligned (crashbox diameters are different) which induces bending moment.
  10. Hi, the geometry has to be properly partitioned before using automatic hexa mesher (one volume, multisolids). In case of complex shapes, it is challenging to properly partition the solid in order to be mappable in one or more directions- it is even more challenging to strategically plan how these mappable solids come together to produce a structured mesh. Unfortnately, there is no easy fix for hexa meshing as it is the most difficult type of meshing. Refer to the following for details: https://www.altairuniversity.com/wp-content/uploads/2012/04/HM_SolidMesh_Extract.pdf https://altairuniversity.com/wp-content/uploads/2012/03/Bracket_Geometry.pdf https://blog.altair.com/art-of-map-meshing/
  11. Hi, this is a strange issue. However, the issue is resolved in recent versions as /ADMAS no longer requires visualization node and the COG is computed correctly. Therefore I recommend updating the version you are using.
  12. Hi, there are modeling errors: -3 beam elements have collinear nodes (invalid orientation node). Use the 1D>beam>update panel to resolve this issue. -remove intersections and penetrations with tools>penetration check -the timestep imposed is a bit too high TP004_2_edit_0000.rad The deformation starts at the base of the upper crashbox due to random mesh flow lines that behave as a geometric imperfection. 2-D quad mesh should be systematic (ruled or mapped), avoid 2-D auto mesh: Flow lines should be maintained with minimum number of trias and diamond or rotating quads should be avoided. Use of the auto mesher on surfaces sometimes results in a zig-zag or random mesh which might lead to unexpected problems later. Better Mesh Flow: For crash or non-linear analysis, systematic mesh flow lines where all the elements satisfy the required quality parameters is very important. Using a mix-mode element type instead of pure quad element type helps to achieve better flow lines and convergence of solution. Refer to the page https://www.altairuniversity.com/wp-content/uploads/2014/02/2Dmeshing.pdf
  13. Glad to help. You need to split the geometry into design & non-design components using geometry>solid edit>trim with nodes, lines or plane/surf. Solid_Edit_Panel.pdf
  14. Hi, it is common practice to create a rigid (RBE2) spider and apply the load to the independent node. In general, it is best not to apply loads and displacements directly to design spaces, as this often leads to incorrect results. Instead, you should split the part into design and non-design spaces, and apply loads and displacements to the non-design spaces.
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