# Imre

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50

1. ## Second order element in composite modeling

Hey Rahul! Thanks for the quick answer. I am aware of this ebook and find it pretty useful. I think I will make a few test to compare the two methods.
2. ## Second order element in composite modeling

Hey Guys! I've just wondering, it is useful to apply second order element for composite in Hypermesh using Optistruct as a solver? I think the composite theories use pretty much linear approximation between layers that's why I'm asking this "silly" question. Thanks for answers in advance! Have a nice day, Imre ps.: if you have any good tutorial, books etc. for composite modeling I would be grateful if you can share with me! :)
3. ## Constraints in HyperMesh

Hey guys! I would like to do a linear thermal analysis. I would like to catch the proper behavior of my system that's why I used constraints in the thickness direction of a thick aluminium plate. The plate should dilate in all direction but the top side of it. How can I apply such constraint which allows the displacement of a node in the positive direction of an axis and obstructs the DoF in the negative direction? Should I use some kind of contact for this purpose? Thank you for your time and your answer in advance! Kind regards, Imre
4. ## Insert laminated into composite plies

Hi Premanand! Thanks for the answer, I couldn't find this topic because I had searched for keywords "inserts", "composite" etc... The topic what you linked in is very helpful, thank you for it. Do you or anyone know which is the best way to model this kind of "rip out problem" if it's important to catch the real behavior of the rupture of the composite plate? I think solid element would be better option in this case but I don't know how can I model properly composite with solids. Are there a same solution like in the case of shell elements: create plies and then a stack laminate or should I create all the solid elements separately? In that case it would be very thin solid element which could cause inaccurate results. Thank for the help!
5. ## Insert laminated into composite plies

Hello Altair Community! I would like to model a so called "bighead" insert which is laminated between the plies of a composite plate. I want to simulate the rip out and measure the force etc. So how can I model properly this problem? I attached an image where you can see how I want to model this insert. Should I use solid or shell element? If I use ply-based modeling I can not find a way to model a bighead between plies. Thank you for your answer in advance!
6. ## Polar chart in HyperLaminate

Hi Balázs! Thanks for the information, I will try it. Kind regards, Imre
7. ## Polar chart in HyperLaminate

Hey everybody! I've just tried HyperLaminate modul in HyperMesh and found that it can calculate the stiffness of a composite laminate, the [A] [D] matrices etc. as you can see on the attached images. Is there any tool which represent the stiffness of the laminate in polar chart? I think Ansys is capable of doing it, but I could not find this function in HyperWorks. Thank you for your answers! Kind regards, Imre
8. ## Unit of OptiStruct

Hey guys! I saw one composite optimization tutorial where the units of the results were not S.I. (lbs, ft etc.). My question is: how can I modify the unit of my input parameters? So far I thought that Optistruct use mm, s, MPa, ton as unit and I have to calculate the conversions between different units of measure. Thanks for your answer in advance! Best regards, Imre
9. ## OSSMOTH problem

Hi Prakash! Thanks for all of your help! I am aware of tip&trick topic on altairuniversity website. I like the support and the development of the Altair, thanks for all! Best regards, Imre
10. ## OSSMOTH problem

Hi Prakash! Thanks for your help! With Geometry ply smoothing I was able to get something similar. I think I have just to make some magic with the settings (iteration steps, area ratio etc.). I read a former topic about the ply-shape smoothing where you wrote that "Area ratio: local region area / total design area (real value between 0.0 and 1.0. Default=0.01)". Are the area ratio calculation method the same in OSSMOOTH and in the Geometry Ply Smoothing (in Aerospace menu)? Ps.: where can I check such tip&tricks that you wrote me before about the debug control card? I did not find the debug card in the HM, HW, or Optistruct help. In the help of control cards that is all about debug card: "Some special or custom features can be accessed through the use of 'debug, <string>, <real>' statements.", which is not so much help for me. Thanks for your help in advance! Imre
11. ## OSSMOTH problem

Hi Prakash! I add control cards DEBUG, FS-SPLIT. After the free-size I got 16 plies just like in the tutorials, and the shape and thickness of the plies were the same. But OSSMOOTH algorithm seems a little bit problematic as you can see on the picture. I sent you the updated .fem file via your file transfer page. Could you run an OSSMOOTH with the same settings to see what kind of results you got? Thank you for your help!
12. ## OSSMOTH problem

Hi Pagadala! Of course I can share the file. I send it via FileTransferLink.
13. ## OSSMOTH problem

Hey guys! I made a tutorial of composite optimization which contains a ply smoothing steps. The name of the tutorial: OS-T: 3400 Design an Open Hole Tension (OHT). The model setup was the same and I got the same result for linear static analysis just like in the tutorial. The optmization went well, I got the same result as you can see on the attached picture. In the tutorial the name of the plies are different because I use the version 2017.2 . I have 2 plies which contain the same element like in the tutorial. After free-size optimization I made the next step: OSSMOTH. It gave me some funny result as you can see on the pictures. You can see the settings are the same and the results still different. On the 3rd picture you can see the OSSMOTHING result from the tutorial. You can see that the settings are the same but the results are very different. Could someone explain why I got so different result? Thanks for your answer in advance! Best regards, Imre
14. ## Sizing design variable

Thank you very much, it is working fine.

Thanks you!
16. ## How can I check the composite stress in the fiber direction?

Hi there! Thanks for the quick answer. I was aware of these output requests but I did not know that proper meaning of the composite stresses: P1, P3, normal stress X, normal stress Y direction etc. How can I check the stress in X direction of a ply? X direction is respect to the fiber orientation of the ply, so these stresses is interpreted in the ply system?
17. ## How can I check the composite stress in the fiber direction?

Hey Guys! I would like to check the stress in the fiber direction in a composite body. I did not find XX stress, or P1 stress for a given ply in the fiber direction or perpendicular to that. How can I check these stress and strain values? Thanks for your help in advance! Best regards, Tüki
18. ## Sizing design variable

Hey guys! I have a problem with composite optimization. I would like to ask you to help me modify a script. I have made a composite skateboard tutorial and after size optimization there were many plies. These plies have initial values like 0.41535 mm, and upper bound value something similar, but bigger. The manufacturable thickness was 0.5 mm, so I had to alter the upper bound value equal to multiple of the manufacturable thickness. I found a script on the script exchange, which is attached, that can change the upper bound, initial value and lower bound of the design variables for the multiples of the manufacturable plies. I think it would be useful if this script would be able to modify the upper bound value of the design variables in the following way: If the initial value (IV) is less than or equal to the manufacturable thickness (TMANUF) then the upper bound value of the design variables (UBV) has to be equal to the manufacturable thickness (TMANUF). If TMANUF < IV <= 2 x TMANUF then UBV = 2 x TMANUF Generally: If n x TMANUF < IV <= (n+1) x TMANUF then UBV = (n+1) x TMANUF; where n = 0, 1, 2, 3 ... Could someone modify this script with this changes? Thank you for your help in advance! Best regards, Tüki Readme.txt Update_sizing_desvars.tcl

Hi there! I'm also interested in such case of connectors. I've looked into the connectors training what Sanjay attached and I think the best way to model adhesive bonding is the adhesive connectors with mid thickness option. In that way the real adhesive thickness is used unlike the shell gap option. If you use area connector thickness within 5 and 10 mm your results could be very confusing, and I think it is not so realistic. It would be useful if you have any measurements data to validate your model, without that I would not use such unrealistic thickness. "The maintaining perpendicular constraint" is interested. I do not know the proper answer. Sanjay, what do you think, why is this perpendicular? In this case could be a geometry nonlinear problem? I think the displacement is too large for Linear Static analysis and for small displacement theory. Sorry that I couldn't help, but I wanted to comment here, because I'm interested in this adhesive bonding problem. Thanks for the question and the answer guys! Best wishes, Tüki
20. ## Composite coupon test in Optistruct

Hi Prakash, Thank you for your support and help. Is it possible to apply displacement for load in Optistruct? In RADIOSS I saw a tutorial for 3-point bending so it would be perfect for me but later I want to use my material card to calculate some linear static problem on more complex composite structure. That's why I would like to use Optistruct in first place. Is it recommended to use RADIOSS for material card validation/creation and use that material card in Optistruct? What do you think the overlap of these two solvers? Thanks for your help in advance! Best regards, Tüki
21. ## MotionView importing problem: CAD or FEM model (with mass and inertias)

Hi Prakash! After you wrote that you haven't had a problem to import the file, I tried a few things. In nutshell, my problem was that there was an accented character in the reaching path (my name was the folder name too). So problem solved, thanks for your quick help, I am obliged! Best regards, Tüki
22. ## Composite coupon test in Optistruct

Hey Guys! I have experimental data for composite tension compression and bending (3-point and 4-point) due to my university and I want to make a material card that can describe all of the mentioned test (and behavior) with proper accuracy. I would like to make tension, compression and bending (3-point and 4-point) test in Optistruct but I haven't make coupon test before. In the real tests the loads (movement of the clamping jaws) move at constant velocity. I have no experiment how to model such kind of load in Optistruct. I think there should be some non-linearity in the test because of the large displacement. How should I properly model such kind of problem? Do you have any experiment in modeling with velocity load in Optistruct? A further problem will be the bending tests where I think I should use contact surface to model the geometry of the bending machine tool's head. In Optistruct I used slide contact before, but it didn't work to well because of large displacement. Is it possible the handle open gap contact and make the 3-point/4-point bending in Optistruct? If you have any model for bending and tension and compression could you share with me? I would like to study the pre-process method to understand the nature of the coupon test in Optistruct. Thank you for your help and advise in advance! Best regards, Tüki
23. ## MotionView importing problem: CAD or FEM model (with mass and inertias)

Dear Praful, I'm using the version 2017.2, regarding to ConnectMe it's up to date. I've tried to import in HW 14 too but hasn't work as well. I've tried what you wrote (import, save and reopen) but didn't work. I share an assembly step file with you, please try to import it and share the result with me. Thank you very much in advance! Regards,
24. ## MotionView importing problem: CAD or FEM model (with mass and inertias)

Hey Guys! I have faced the next problem when I tried to Import CAD or Fine Element Model With Mass and Inertia in Motion View. The STEP file was imported and you can see on the attached image the „bodies” but the „graphics” aren’t visible. It is written at the Graphical source that "error evaluating". I tried to import in the 2017 version of HW, but it didn't work due to importing/conversion error. What did I do wrong? Could you please help me in this matter? Thank you for your help in advance! Best regards, Tüki
25. ## Import from .csv to .rad

Hey Guys! I would like to ask you that do you know such kind of script that could import data from a .csv file and export it to a .rad file to change material data or something. I would like to accelerate my work in RADIOSS to manipulate the .rad file. I would like to change the .rad file as fast as possible, that's why I thought about script. Thanks for your anwer in advance! Best regards, Tüki
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