Jump to content

Jan Grasmannsdorf

Members
  • Content Count

    35
  • Joined

  • Last visited

  • Days Won

    3

Everything posted by Jan Grasmannsdorf

  1. Hi, if you would like to transfer and copy a mesh from one surface or component to another, please use these functions (described in the pulldown menu): Mesh - Translate - Elements - if you would like to translate the mesh along an axis Mesh - Rotate - Elements - if you would like to rotate the mesh at an axis Mesh - Project - Elements - If you would like to adapt the mesh to a new plane Morphing - Map to Geometry - if the mesh should adapt to a new (e.g. curved instead of planar) shape To create a copy, make sure that you select the "Elems - DUPLICATE" option in the yellow entity selector. For this you first need to select the original elements and then hit the yellow selector and select "duplicate" to create a copy that will then be translated, morphed etc. Jan Mesh_Transfer.mp4
  2. Dear Altair Teams, please find attached the starting document and data for the science hack this weekend. We would like to wish you a good start. Post your questions within this Forum. You might also upload data or models within this Forum. Thomas, Lorenzo, Jan and the Altair Team Altair_Climate_Model_StartHere.pdf ChallengeData.xlsx
  3. Hello, as you are using shell elements, the material orientation x-axis (= E1) is by definition always in the local XY plane of the shells. In your case, you might need to consider a Solid Element model, to have a local E1 orientation in parallel to the z-axis. The material law would then be MAT9 or MAT9ORT. Jan
  4. You could use the "GPAD" Option in your contact parameters, to define a certain thickness of the contact, derived from your beam section. This could be probably done automatically, using a script.
  5. Maybe Morphing with "Map to Geometry" would be a faster approach to your task: https://www.screencast.com/t/xSRuc0nQX
  6. Here is the link to the video, explaining the contact definition: https://www.screencast.com/t/nK1NO4swbn
  7. Hello, attached is a model, that describes the contact definition using the "adjust" option. To define a contact, you have a mesh of 2D Elements and an element set on the outside of your design space and a node set containing your 1D nodes. The adjust Parameter needs to have the distance in which to search for the contact and then pushes all slave (1D) nodes to the shell. In the standard definition, the Shell Thickness is considered but not the 1D Diameter. So to avoid penetrations please set the PSHELL Thickness larger than twice your maximum Beam Cross section. In this video, the beam section is 7.7, so I set the PSHELL to 16 > 2x7.7. The Pushout direction during the adjust is influenced by your Shell Normal direction, so you need to seht the "MORIENT" option in your contact definition. To get the final position, use the "position" measure in HyperView or the corresponding OML or TCL language command in COMPOSE after reading your H3D results. Jan contactProblem1D_Altair.hm contactProblem1D.h3d contactProblem1D_Altair_ManyContacts.hm contactProblem1D_Altair_manyContacts.h3d
  8. There is no visco elastic material in Optistruct. You can implement User materials for this.
  9. Currently I’m working on my thesis and for this I’m using Hypermesh 2017. I have a few questions regarding Hypermesh 2017 and I would be really thankful if you could help me: I’m using a model, with 6 sides, which should be constrained with MPC on 3 sides and also be restrained on the other 3 sides. I actually couldn’t find the exact option for the restraints, so I guessed the best option is to use the “Suport1”. So I wanted to ask you, if you would recommend this “Suport1” for restraining the model or is there another option to restrain? The question here is: what do you want to achieve? To constraing the structure by locking single degrees of freedom to zero displacement, please use the SPC type for constraints. The MPC type is meant to lock a degree of freedom from one node to another node (e.g. Node 1 should move the same amount in x as Node 2) The Suport Constraint is meant only for inertia relief analysis - so for cases in which you constrain a structure by defining an opposing force (e.g a plane wing in the air is held by an opposing inertia force). The Force/Pressure which should be applied to the model increases in proportion. So I wanted to ask you, where do I find the option to solve this Please use the "equation" option in the forces panel to define a force / pressure distribution which is e.g. linearly increasing Which is the best Material Card for ABS (acrylonitrile-butadiene-styrene) in Optistruct? I have the stress-strain-curve and also the values for E, Nu, and Rho? I can't really answer this, as it depends on your material curve (which I do not know). For a general stress strain curve, please use the MATS1 Material model MATHE would be the correct material, if your material has a hyperelastic behaviour Is there a Material Card for Visco-Elasticity Material in Optistruct? Is there an option to define MPCs and Restraints in Radioss Block100? Or is this only possible in Optistruct? You can define constraints also for the RADIOSS Solver by using the RADIOSS User Profile in HyperMesh
  10. Hello, you can export any mesh point coordinates by using the File -> Export -> Solver Deck function in HyperMesh. Please make sure that you choose a user profile (at the start of HyperMesh) and format that is supported by Catia V5. Then you should be able to import the HyperMesh generated data into your CAD system. Jan
  11. Dear Mr./Ms. currently, I am looking for a way to generate points (in 3D) over a random surface. So far I see some very impressive futures in HyperMash. I wonder if there is an opportunity to export the points that are generated with the mesh. Ideally, i would be able to generate a mesh and then export the points to CATIA V5 where I can use them.
  12. Hello, there might be many reasons, why you wont get the same result between two different solvers. For a linear static analysis in HyperWorks, your model looks fine, so I would definitely trust the results that you are getting. The reasons why they differ from Ansys might be: 1) In Ansys, you might have different Element Type (e.g. Tetras instead of Hexa / Brick elements) or a different element order (you use 2nd order elements in HyperWorks) 2) Ansys workbench might change or adapt your input or boundary conditions without notifying you, e.g. at the constraint locations 3) maybe you use a linear static analysis in HyperWorks and have defined something different (large deformation or non-linear analysis) in Ansys? 4) You might have a different location of your stress ( in HyperWorks stress is at the element center by default)?
  13. Hello, there are several ways to put two or more parts into contact in HyperWorks for the OptiStruct (and other) FEM solvers: 1) To have a defined identical and connected mesh node pattern on both contacting surfaces 2) To have a defined "FREEZE" Contact definition between non-identical mesh patterns The first way - identical mesh patterns - is described in the first flash video attached to this post. There is a second video that describes the creation of identical meshes in case of unconnected contact surfaces (gap between the two CAD parts) The third video describes the automatic seupt of FREEZE contact between multiple parts. I also attached the HM 2017 models to reproduce the videos. Best Regards Jan 01_03_Kontakt_Geom.hm 01_Mesh_Identical.swf 02_Kontakt_Geom_Gap.hm 02_Mesh_Identical_Unconnectes.swf 03_Contact_Freeze.swf
  14. How can the display of the applied the load vector in HyperMesh be changed from the load tip to the load tail point? Answer: There is a display option (HyperMesh 2017) to change this display - see screenshots
  15. Question 1 I tried to create a Tetra Volumemesh, but unfortunately can't pick the surfaces that are requested in the menu Answer: Please change to the "Element" or "Comp" Selection in the submenu "Tetra mesh". This will allow to create a tetmesh based on surface elements. The submenu "Volume Tetra" asks for a selection of "CAD surfaces", which you do not have in your model. Question 2: I performed a re-analysis of my results. Now I will see two different result windows - one for the design results and one with the structural loadcase results. Is there an option to see the two results in one common result plot (= 1 result file with density and displacement results)? Answer: You can define the Entry "DENSITY, H3D, ALL" in your optimization inputfile (in HyperMesh through setup - create - control cards - DENSITY): this will allow to plot the displacement or stress contour on the optimized iso surface in HyperView (density and displacements will be in one common result file). Jan
  16. In addition, there are some more issues in your model: 1) the "bellkrank nondesign" parts are not connected to the shaft (2D mesh hits a 3D mesh, but there is no connection made) . Therefore no load is transmitted via this interface. I recommend to use a TIE Contact between the two parts. 2) The "rotation" of the shaft in the mounting will not transfer any load from the shaft to the SPC at the end of the mounting. You will get a rigid body mode. I would suggest to use a Slide Contact between the Shaft and the mounting, instead of the "Rigid + Revolute Joint". Another approach would be to use "Multibody dynamics" in solidThinking Inspire and model the kinematic behaviour first. After this, the resulting forces could be mapped to the single parts and then used for optimization.
  17. Hello, in your model, you used the Joint of Type "JOINT", which is meant for Multibody (Kinematic) analysis only. Therefore, currently your shaft and mounting are not connected via the joint. To consider a revolute joint in FEM (Static), you should use the joint type "JOINTG", which is defined in the same way and menu in HyperMesh, except for the option "FE" instead of "MBD". To Model the JOINTG within your model, you also need to define a local coordinate system prior to modelling the joint. Here is a flash video, how to do so: Unable to display content. Adobe Flash is required.
  18. Dear Mr. Grasmannsdorf, I would like to ask how to define Revolute Joints for an FE Analysis with OptiStruct. I modelled a Shaft which should be constrained in a mounting, except for the revolution around the shaft axis. What would be the appropriate way to model this constraint? I used two Rigid Spiders within the shaft and mounting and a revolute joint to connect the rigids. However in simulation the model seems to be unconstrained and is not kept at its location. What do I need to consider when modelling revolute joints or how else could I model the desired constraint? Mit freundlichen Grüßen
  19. Hello, to answer the question on linear vs. other functions: A linear function is less likely to have local minimums or maximums, as opposed to more complex functions as shown below: You also asked via mail about the Global Search Option: This is documented in the help of OptiStruct under the Keyword "GSO" or "GLOBAL SEARCH OPTION". I think the comments section on the DGLOBAL Bulk Data Entry is also quite useful for additional information on how the parameters NGROUP etc. are defined? Jan
  20. Hello, it seems that your optimization setup has a high chance to be "caught" in a local optimum. When you start with 9.0 as your initial design variable, optistruct doesn't find a way to leave the local optimum and therefore converges in 1 iteration. The initial value of 1.0 however hurts the design constraint of displacement > 0,00012mm and forces the solver to "react" to this constraint violation - and leads to another (local) optimum. To overcome the effect of local optima, you can use the DGLOBAL search function and start your optimization with multiple starting points to find a global optimum. I see that this card is already included in your setup but hasn't been activated. Activate the DGLOBAL entry and you will get a solution with an optimum and the best setup for starting values of your Design Variable. Best Regards Jan
  21. Hello, the Issue is related to "German Language" in the "Preference Settings" of Basic FEA in Altair Student Edition 14. You can either upgrade to Student Edition 2017 on our website https://secure.altair.com/onlinestore Or you can try the following settings to "English" in the Basic FEA UserProfile - change then the User Profile to OptiStruct - and then back to Basic FEA to avoid the error: https://www.screencast.com/t/g7TWVY4h Jan
  22. Dear Jan, I have a question about HyperWorks. When defining the material orientation for composite rim design I tried to let it follow the outer part of the rim, but it isn't working. Do you know if it is possible and what the command is to do this? Another question we have is whether it is possible to use some kind of circular pattern command to use on plies and how it works. Thanks in advance! Kind regards, Pieter Dear Pieter, to define the material orientation along a rim or a certain shape, I would recommend to use the tool within the Aerospace toolbar to define orientation along lines or node paths. Here is a short video that describes how to access the function: http://screencast.com/t/oLcdJC8jH For circular patterns, please define a user defined coordinate system type "cylindrical". you can then use this system to define a circular pattern along the circular system axis. Here is another flash video that describes the procedure.http://screencast.com/t/UaoJGtQX Jan
  23. Hello, to define a composite failure criteria within HyperMesh (for the solver OptiStruct), you should define the following entries: 1) Define the allowable stresses and strains within the Material (MAT8) definition - Xt, Xc, Yt, Yc, ... 2) Define the Failure Theory (FT) within the PCOMP or PCOMPP property 3) Activate the "Output Results" option within your single PLY definitions 4) Create a "CFAILURE" output request within your load step (OUTPUT option) or globally for all load steps (Setup - Create - Control Cards - Output - CFAILURE) Jan
  24. There is no direct way to influence the automatically created crash.hm file. It should not happen that the automatic save goes wrong, but unfortunately sometimes it does. A way to restore your data is to import your last solver deck (like *.fem file for OptiStruct solver) through file - import - solver deck into HyperMesh. This solver deck is created everytime you run a simulation and therefore should contain all your relevant FE data. The solver deck does not contain the CAD geometry however. Best Regards Jan
  25. Hello, when HyperMesh closed down suddenly, a crash0.hm file has been saved on my computer. Unfortunately some of the entities (like Plies etc.) are missing after the HyperMesh Crash. How can I prevent this?
×
×
  • Create New...