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    • Rahul Ponginan

      Please click here for a short but important announcement   03/26/17

      Dear Users Our Commercial and Academic users around the world can use these same forums here as before i.e. the Altair Support Forum , Commercial users from India with solver queries can go to the Solver Forum for India Commercial Users , Academic Users from India and AOC India Participants are requested to go to the Forum for India Academic Users and AOC India Participants , We will be tending to all queries in all the forums promptly as before, thank you for your understanding. 


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Showing most liked content since 02/21/18 in all areas

  1. 3 likes
    Hello Everyone Firstly thanks a lot Livil for all the help. Really grateful for it. Secondly, here is the file which Livil wrote, in case any one needs it in future. merged.tcl
  2. 2 likes
    Hello, You can do this using TCL. First open the command Window Go to View>>Command Window Then type the following code: *createmark elems 1 displayed hm_getaverageelemsize 1 This will give you the average element size. credits @tinh Thankyou
  3. 2 likes
    Hi, For an elasto-plastic material you can use /MAT/LAW2 or /MAT/LAW36. If the user is having a stress-strain curve use /MAT/LAW36. Create the function usinig curve editor (XYPlots>>Curve editor) and in the material card recall this function as shown below. Please note that the stress-strain curve should have post yield values. Also,the first point of yield stress functions (plastic strain vs stress) should have a plastic strain value of zero. As an example, If the yield value is 90, the curve starts with X Y 0 90 For rigid bodies always use /MAT/LAW1. /MAT/LAW13 is an obsolete card now. As in Dyna you can create a self/global contact in RADIOSS using the Type 7 contact. Select the master and slave as the same and a self contact between them will be established.
  4. 2 likes
    Hi, It's simple: *displaynone *createmark elems 1 "equal to value" propertyidflag 1 *findmark elems 1 0 1 elems 0 2
  5. 2 likes
    Thanks all ! What I want has been achieved by creating the result of { Z1(or Z2) - Mid } layer's von mises stress in "derived results"
  6. 2 likes
    Hi, I have worked in FOAM Material using LAW 70 in one of my project. I tried validating LAW 70 for different scenarios. Attaching some sample validation case for reference. Hope it may help you. Thanks. Comp_20mm_0000.rad penetration_1DOF_0000.rad E_1100_0000.rad
  7. 1 like
    I think if you change your model, you have to rerun the simulation because it is a particularity of fem
  8. 1 like
    @dracu777 That means if you applied the displacement at the node for dof1 in type SPCD. You need use the SPC to constraint the same node for dof1.
  9. 1 like
    Hi Pohan, You don't need startnotehistorystate and end endnotehistorystate. All you have to do is: *createmark components 1 "RW_left" "RW_right" "Compresseur" *deletemark components 1
  10. 1 like
    Hi try removing space in front of comp names you have excessive createmark and clearmark commands at line 2 & 3, they are unnecessary.
  11. 1 like
    Hi Abhi, Is this an explicit run? If yes, the event time is very huge and I think it will take a long time to run... and this is why you see "1 Engine Running" Also, you should see A01 files in your working directory which are interim animation files. If you are using student editions, you cannot use these to view results though. Apart from this, I see that there are no slave nodes defined for Rigid wall. Please check and update and select the event time accordingly. 1e6, I think very huge
  12. 1 like
    Hi Tinh, Thanks for your reply ! I already did this In place of Geometry i have selected all the given surfaces of the geometry, it has executed but created really wierd surfaces and also this program has detected only few surfaces to execute. Thanks ! Regards, Ashish
  13. 1 like
    Hi, It keeps a track of all the operations you're doing in HM. It saves automatically in background.
  14. 1 like
    I can make template for that. Please describe your vtp and vtu formats If it is not so long, it's free for you!
  15. 1 like
    please constraint all its nodes by rbe2 and rerun
  16. 1 like
    Thank to symmetry, we work only with 1/8 Splitting plate surface Mesh 1/4 circle area (of plate) and named "2D_1" component: Mesh all surface: Make 3D mesh of Cylinder part by using "drag elem" Get 3D mesh of Cylinder Drag elem (2D_1 and 2D_2) to make 3D mesh of plate: Get 3D mesh of plate: Make symmetrical operation: And finally make equivalent of nodes: The final mesh: HM Model: Square_Cyinder2.hm HTH,
  17. 1 like
    Hello, Try to export your model as h3d including FE and geometry (see picture). In Hyperview you can import it as model. The geometry is represented by STL triangle elements, i think. If you need it separately, move or copy the geometry into extra components. Best Regards, Mario
  18. 1 like
    Hi, I said above, you need to enter 2 commands: hm_setpanelproc hm_resetmenu hm_pushpanel penetration
  19. 1 like
    You can export these parameters to the *.out file. Presently this option can only be enabled in EDITFEKO under the CS card. Basically after setting the up your model and meshing it in CADFEKO, from there, run EDITFEKO. Find the CS card(s), click on them and hit F1 to edit, and check the box "Export cable parameters to *.out file", save and run FEKO.
  20. 1 like
    The Characteristic Mode formulation for dielectrics solved with the surface equivalence principle (SEP) results in a set of eigen modes that contains both internal and external resonances. The internal modes (sometimes call non-physical or fictitious) do not radiate any power, and are thus removed from the result set. It is advised to increase the number of modes requested when dealing with such models.
  21. 1 like
    Hi, which option would you like? I see thickness option is "component thickness" which is same as in v14 v2017 can check it base on contact so I think it's better It just hides the original panel. If you still want to use it, try enter commands (in menu View>Command Window): hm_setpanelproc hm_resetmenu hm_pushpanel penetration
  22. 1 like
    Hi Prakash, Thanks for your time in trying to solve this issue I however managed to solve this issue. In my input deck, there is a line which I forgot to comment out. DIAG 8,13 This line was used in my Nastran input deck. When i convert it to Optistruct, i forgot to comment out this line.
  23. 1 like
    ooh, I should have mentioned that I also changed the MORIENT in the contact group to NORM and in PCONT, I activated STFEXP. It was blank before. That might have been the reason for the contact error. Not sure though because I am new to this.
  24. 1 like
    Hi tinh, thanks for your answer but finally I could do the script. Anyway, what I had was this (bolt made with several 1d elements): And what I wanted was this (a tag with a ID for the bolt, i.e.5003) : But as I said before I could develop de script. You can delete this topic if you want considering it doesn't contribute to the forum. Many thanks.
  25. 1 like
    Hi @LKZ Makes sense. I will check with experts if there is a better to use RBODY in OptiStruct.
  26. 1 like
    Hi sure, hm_getclosestnode is not working with local coordinate, you have to provide global coordinate maybe, there is some commands to calculate global coordinate, please search them below I will create a node at that position, and retrieve its global coordinate to provide to hm_getclosestnode *createnode 0 0 25 658001 ; #create a node at the coordinate set NodeId [hm_latestentityid nodes] set gx [hm_getentityvalue nodes $NodeId globalx 0] set gy [hm_getentityvalue nodes $NodeId globaly 0] set gz [hm_getentityvalue nodes $NodeId globalz 0] *createmark nodes 1 -1 *nodemarkcleartempmark puts [hm_getclosestnode $gx $gy $gz]
  27. 1 like
    Please refer attached video. Deformed_with_fem_format.mp4
  28. 1 like
    Hi, if the quads have 2 nodes sharing same position, they will have minsize = 0, so please check F10>min length 0 (set calculation as "shortest edge"), you will catch the quads
  29. 1 like
    Hello, You can assign mass to node using the 1D>>masses. Please keep in mind the units system. Then to add inertia go to card edit panel: select the proper element, assign the config as mass and type as CONM2: then click on edit and enter the appropriate values. Thankyou
  30. 1 like
    Hi Novak, Are you able to get the desired result from the file? If you're getting what you want you will have to return lst_dispInfo from GetNodalContourValue and set sigma values directly in the below loop like this: foreach n_id $::curSel { set sigma_1 [::hw::post::custom::GetNodalContourValue $n_id "YourResultType" "YourResul/direction"]; #should be matching the file. set sigma_2 [::hw::post::custom::GetNodalContourValue $n_id "Displacement" "Y"]; #should be matching the file. set sigma_2 [::hw::post::custom::GetNodalContourValue $n_id "Displacement" "Z"]; #should be matching the file. ShowCurves $sigma_1 $sigma_2 $sigma_3 #Stress values } If you're authorized to share files, please share result and developed code in the below link. I will give it a try. https://ftin.india.altair.com:8443/filedrop/~QUK1Ji
  31. 1 like
    Hi @LKZ According to OptiStruct help, Pretension force/adjustments are output in OptiStruct result format (.pret file) and right now it is not available in H3D format.
  32. 1 like
    I would typically start with Spalart Allmaras. It's pretty good with most flow conditions. Also - you may want to upgrade to the latest software version.
  33. 1 like
    Unless the structure is completely closed (waveguide or other non-radiating structure), it is difficult to predict what solution method would be the most efficient. You model does have a very thin substrate and that would lean towards FEM (usually). Since you have a radiating structure, you need to add a reasonably sized air box on the front of the structure (where the patches are). I would also use 1st order FEM, since you want to mesh fine. I hope some of these suggestion help.
  34. 1 like
    Invite me as ... contest jury!
  35. 1 like
    Hi, You can consider Mat LAw 28 for modelling honeycomb material in RADIOSS. Concerning the question about periodic boundary conditions: We have multi-point constraints for nodes but I think it would be a lot of work to define all the MPC for a large number of elements. Please go through Multi-Point Constraints (/MPC) in the Help Menu for more.
  36. 1 like
    The reason for the error is that lossy metals (copper) is not supported on the FEM / MoM boundary. You need to either make the outer metal PEC or add an FEM air region around the metal so that the FEM / MoM boundary is the "air" region that you add. However, looking at your model, I think the problem is rather the fact that the patches have losses and you will have to add an air region in front of the patches if you want to use FEM. Have you tried using MoM for this model? Is there a particular reason why you want to use FEM? Regarding the meshing, the only thing I can think of is that you can try to create a "unit cell" of the patches and then mesh it. Once you have the unit cell, you can duplicate the mesh for the unit cell. This makes editing the model quite a bit more complex, but it is possible. If I were to do that, I would use scripting. I don't have any other suggestions. We are working on features that would (or could) make meshing these repeating structures easier in the future (but it is still early and in a concept phase). Even with the meshing as you have it now, I'm not convinced the mesh is fine enough for accurate results. I would definitely do a mesh convergence study and also try a few solution methods and settings.
  37. 1 like
    Hi LKZ, The node which is given the enforced displacement (SPCD) must also be fixed in same DOF using SPC
  38. 1 like
    Hi You can get the solid id in the variable 'id' as following: set id [lindex [hm_measureshortestdistance2 0 76 81 solids 2 0 0] 4] or lassign [hm_measureshortestdistance2 0 76 81 solids 2 0 0] d dx dy dz id Hope it helps.
  39. 1 like
    Hello, Can you please try and deactivate this option: If this does not work, i don't think there is any other way to hide the points as those are topological points. You can only delete them or suppress them (ignore during meshing) Thankyou
  40. 1 like
  41. 1 like
    Hi Pratik, Explicit scheme is a function of time and the explicit algorithm works in time step increments.Time step is the time required for a shock wave (governed by the speed of sound) to propagate across the smallest distance of the element. A run is a single model simulation and it starts at time zero and continues till the user defined endpoint is reached. From the above relation, it is clear that both material modulus and density control the speed of sound. The solution time step is inversely proportional to the speed of sound. So, if the material is stiffer (higher modulus of elasticity), the speed of sound increases resulting in a lower solution time step. Thus, to keep a stable solution, the shock wave through a medium must not pass across more than one element per time step. This implies that the length of the element is the modeling parameter that affects the overall solution time. Usually explicit analysis lasts only for a certain milliseconds, like crash, impact, drop...etc. Basically the user should get enough experienced in explicit analysis so that before running the analysis user can estimate a rough run time. Based on the energy plots once the system is stable we will terminate the run and thus a run time is calculated. In your simulation in order to achieve such a high deflection the run time was estimated for 4sec and hence I asked you to run with OptiStruct as your case is not an explicit one. Regarding the number of animation files, we always recommend to write 30-40 animation files which will give a smooth result.
  42. 1 like
    Well, maybe this how it was programmed at the beginning. Proposed, In next version shuffling with MAXSUCC constraint will support all angles.
  43. 1 like
    Alot of work to make this H3D From your output.res => Extract nodes & elems information => make *.hmascii => Import into Hypermesh => Export to *.fem From your output.res => Extract results. In my test, I tested with nodal displacement of 1st step. => write to *.hwascii (I used Perl as scripting programming language) Run Hyperview: Open *.fem as "model" Open *.hwascii as "result" When you have all within Hyperview, you can export again into H3D format.
  44. 1 like
    OptiStruct can only accept one SPC and one LOAD component in a subcase, by default. In other words, multiple load collectors with e.g. different SPC's can't be referenced in the load step panel. There are two ways to apply multiple constraints and loads in a subcase. 1. Put multiple loads in one load collector, and include that one load collector in the subcase. The same method can be used in the case of multiple constraints. 2. Create load collectors for each and every load and constraint set. When you want to apply multiple loads in a subcase, a new load collector needs to be created with the LOAD card (=CardImage=Load). Then, individual load collectors can be combined using the LOAD card. The LOAD card also enables you to associate an independent weighting factor to an individual load collector. In the case of applying multiple constraints, create a new load collector with the SPCADD card (=CardImage), and follow the same procedure as in the multiple load case. Once the combined load collectors are created, they can be applied in a subcase.
  45. 1 like
    Hi Amar, The nodal time step equation is : sqrt (2m/k), where m is nodal mass and k is equivalent nodal stiffness. A scale factor will be also used to calculate the time step. Please go through https://altairuniversity.com/learning-library/considerations-about-time-step/ which is a webinar showing time step calculation in RADIOSS. RADIOSS will calculate nodal and elemental time steps of the model and will choose the highest of these to run. From Check Elems (F10) panel it is possible to determine the approximate minimum time step for explicit solvers based on element dimensions.
  46. 1 like
    Hi, By creating time history output for elements it is possible to output stress and strain for the elements. Go to Analysis>Output Block> elements, select elements. Card edit the created output block and change the keyword accordingly. Use DEF keywprd to output the default outputs. Please go through the Help Menu on Output Blocks which describes about the various outputs available in Time History. Also please go through ths webiniat at https://www.youtube.com/watch?v=Ef7Spn-j7fA&list=PL1u26y75SCrA_BOCLaSewVCNY7xRvCTnA&index=6 which describes about creating output blocks. Using cross plot option you can crate load-displacement curves...etc. The steps for cross plotting is shown in an example file below. Please go through the documents attached. Cross plot values along a specified node path.pdf Cross_Plot.pdf
  47. 1 like
    Hi Ram, There are many online learning sources available for learning tcl/tk scripting. As you get familiar with the language you can review and practice the online tutorials available in our Help Menu. Also please go through this link which is a tutorial on debugging of TCL script : http://www.altairuniversity.com/programing-2/introduction-in-debugging/debugging-tcl-script/
  48. 1 like
    Interface 7 is a multipurpose contact. The node set will be the slave and the surface set will be the master. Gapmin - Minimum gap for impact activation. Type 7 interfaces have a gap that determines when contact between two segments occurs. This gap is user defined. The gap will allow to distinguish the impact. The contact will be activated when the distance between node to surface is less than gap. Igap - If Gapmin is not provided, the contact activation gap can be provided using IGap. If Igap =1, gap will be computed as Gap (master) + Gap (slave), where Gap master will be gm = t/2, t is the thickness of the master element for shell elements and similarly for slave. The the gap will be directly assigned from the property. Similarly other flags can be seen in the Help Menu. FRIC - Type 7 interface allows sliding between contact surfaces and coulomb friction between the surfaces is modelled. No value (default) defines zero friction between the surfaces. Inacti - Type 7 interface is very sensitive to initial penetrations. Inact is used to auto correct the initial penetrations happening due to the defined contact.One method for solving the resulting problems is to use Inacti = 6, where it will automatically depenetrate. When using Inacti =1, the penetrating nodes are deleted from the modelThe correction is only applied to the initially penetrated nodes. The various flags for reducing the initial penetrations in contact using Inacti can be reffered in Help Menu. Idel - During contacts, when elements are deleted, using this option the segment can be removed from the interface. Using 1 option, when all the elements associated to one segment (master/slave) are deleted, the segment is deleted from interface. Where as for 2, it will be deleted if any one element is deleted from segment.
  49. 1 like
    Hi, it is simpler if you write a *.tcl file because tcl commands are not used directly in macro file, example file <Move2dElemsToComp.tcl> : proc ::p_Move2dElemsToComp {{CompName ^2D}} { if {![hm_entityinfo exist comps $CompName -byname]} { *collectorcreateonly comps $CompName "" 11 } *createmark elems 1 "by config" tria3 quad4 tria6 quad8 if {[hm_marklength elems 1]} {*movemark elems 1 $CompName} } ::p_Move2dElemsToComp Now your macro will be: *beginmacro("Move2D") *evaltclscript("C:\Users\demo\Documents\Move2dElemsToComp.tcl",0) *endmacro
  50. 1 like
    Thank you for the kind offer, but I had some help from the helpdesk and using Tool>edges>components>equivalence sorted out all the 312 Errors (it eliminated the free ends on my 1-d elements?):d/