# donggua

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1. ## assembly hex global stiffness matrix

@tinh Thanks a lot for your advice. Yes, what you say is right. Before this I mess up the DOF of global matrix. Now it can work. Thank you indeed. (^_^)
2. ## assembly hex global stiffness matrix

@tinh Thanks a lot for your time. Is this means, I can use the order directly? Just input the order's node coordinate, then calculate the element stiffness matrix. And put the correspond DOF into global stiffness matrix? But I have tried that. It seems not work. Might you give me more detail? Thanks Donggua
3. ## assembly hex global stiffness matrix

Hello, everyone I have a model with hex elements, like below(model.png) : I want to get this model's global stiffness matrix. for element stiffness matrix, I use the local coordinate like the coordinate.png show: I ouput the ( node id, node coordinate, element id, node list of element) for get the global stiffness matrix. But it seems the local coordinate or the order of the node list of each element of hypermesh is different from mine. I don't know how to reorder the node list which I get from hypermesh. The node list order Which I get from hypermesh is show in nodeListHypermesh.png. It seems is anti-clockwise. Thank you so much for your time. Any advice will be appreciated. (^_^)
4. ## How to apply constrains to empty mass center of model

Hi, @tinh Thank you so much for your patient. But I don't learn a lot of FEA, I am a student of computer science. So... I don't know how to calculate it by theory expression. I really don't want to trouble you more. But en~~ may you give me some detail material about this problem? Thank you so much ~~(^_^) I don't know if the problem I want to solve has other method. I just want to add some random forces to model, and get the correspond strain energy. The directions and magtitude of force both random, so the model may fly away. Since this, I want to add a constraint to the mass center.
5. ## How to apply constrains to empty mass center of model

Hi, @tinh I have try to runing it without constraint. But It seems I get the wrong answer, I wonder if I miss something or make some mistakes...The result is shown in the following picture. As I search something from website, I set the inertial relief by using anlysis --> control cards --> param --> inrel set it to -2. When I solve this problem I get different stress distribution and strain energy(calculate by using derived result) from using spc constrain as shown in following picture. I have no idea about how to judge whether the result is correct or not? Thank you so much for your help~~(^_^)
6. ## How to apply constrains to empty mass center of model

Hi, @tinh Yes, yes. I mean this. May I get more detail about inertial relief support from you? Thank you so much for your time and this advice.. Thanks a lot~~(^_^)
7. ## How to apply constrains to empty mass center of model

Hi, @Prakash Pagadala Thank you so much for your reply. (^_^) I have tried the RBE2 element. I think I didn't make the problem clear enough. I can't constrain the node of the cubic, since every node may have force in x, y and z direction, because I add random force to this cubic. The direction and the magnitude are both random. So I can't fix any node on the cubic. I am not very sure if this problem is solvable. Thank you so much for your any advice. Waiting for your reply.(^_^)
8. ## How to apply constrains to empty mass center of model

Hello, everyone As shown in the picture, I add some forces to the model to do the linear static anlysis. I don't want to it move or rotation under that conditions, but the node of the cube can't be fixed in my problem. So I want to fixed the six DOFs in mass center which is the red point in the picture. But the mass center is empty i.e. don't have material and don't have connection with the model. So, the problem is : Is there any method to constrain the six DOFs of mass center and won't effect the result? Can the reb2 element use for solve this problem?(I am a newbie of FEA, I don't familiar with this element) Thank you so much for your time. And any advice will be appreciate. (^_^) Best wishes.
9. ## How can I get stress vs. time curve in hypermesh

Hi, @Prakash Pagadala Thank you so much for your time and patient. I am currently try another method to do my work. I will try your method if my current method can't work well. Thank you again. (^_^) Best regards, Dongying Fu
10. ## How to use force as response

@Prakash Pagadala Thank you for your time. When come to what type of optimizaiton, I think it's not shape/size/topology optimization. Since I have gotten the model, I just want to know how much froce when I apply, this model will get the specific stress. I am not very sure is this idea very strange. Thank you so much. (^_^)
11. ## How can I get stress vs. time curve in hypermesh

@Rahul R Thank you for your time. May you tell me what I can do to get this curve? Thanks a lot.
12. ## How to use force as response

Hi, everyone I am a newbie in hpermesh. As you can see in the picture, I have apply the load to the model. But now I want to know how much force I apply that the model will get the specific stress. So the problems I met are: 1. how to make force as response 2. how to add this specific stress (I guess maybe is the static stress=specific value) I don't know if this is possible. Thank you for you any advice. Thank you for your time. (^_^)

14. ## How can I get stress vs. time curve in hypermesh

Hello everyone, I want to get stress/strain vs. time curve in hyperview, but I have only learned how to do linear static analysis in hypermesh. I try it in hypermesh, but I only get one point in the hyperview 2D plot as the picture shown. I want to know if there are any video or may you tell me how to choose those cards can I get the stress vs. time curve in hyperview. Thank you so much for you time. ~~（^_^）
15. ## How to get strain energy of hyperview

Hi @Prakash Pagadala, Thank you for your reply. When I see your advice and I reopen this model in hyperview, the strain energy is in the result--> scalar. Maybe I made some mistakes at before. Surprising~~ Thank you so much~~(^_^)
16. ## How to get strain energy of hyperview

Hi, everyone I have get some problem when I try to get the strain energy in hyperview like this video show:http://www.altairhyperworks.com/training/new_feature_videos/11/videos/result_math_PartTotalStrainEnergy_final/result_math_PartTotalStrainEnergy_final.htm. And I get a screenshot --video.png-- for easy to understand. The GLOBAL_OUTPUT_REQUEST of control card have been set in hypermesh as the screenshot hm.png shown. But when I use Optistruct to analysis this model, it doesn't have the strain energy in result->scalar as hv.png shown. I am not very sure if I have miss some points. I want to get the strain energy of whole model to make sure my matlab code is correct. Thank you so much for your help, any advice will be appreciated. (^_^)
17. ## how to get the directions of principal stress

Hi, @Q.Nguyen-Dai I send the question to support@altair.com..They reply that hyperworks doesn't support to get this direction.. thank you so much..
18. ## how to get the directions of principal stress

hi, @Q.Nguyen-Dai Thank you so much for you reply. I am so sorry for I didn't express my question clearly. As your screenshot shows, different element have principal stress with different direction. I just want to get the direction/angle in numerical. Then I can calculate something based on this direction. I don't know if I have right expressed what I want to get. I want to a direction in numerical, such as l=(0,0,1) which means the major principal stress direction of one element parallel with Z-axis. Then the l=(0,0,1) is what I want to get. best wishes Donggua
19. ## how to get the directions of principal stress

hello,everyone I just want to know how could I get the direction or angle of principal stress, as it show in the tensor plot. I have been struggling with this problem since yesterday, but I didn't get anything. Thank you for you time..so..much.. Any advice will be appreciated.
20. ## how to get principal stress direction in hyperview by TCL

hello everyone, I want to get the principal stress direction in hyperview by TCL, as direction showing in the figure. I have get the principal stress(tensor value) of this element, but I don't find how to get the directions correspond with the principal stress. Thank you for your time..so..much..
21. ## How to get Elements density of each element in hyperview by TCL

I have solved this problem by polQueryCtrl and polQueryIterator, as code showing in the picture.
22. ## How to get Elements density of each element in hyperview by TCL

hello, everyone I want to get the topology optimization result in hyperview, such as displacement, stress state, elements desity and so on. But I don't know how to get those data. Hyperworks do not write out the hyperview command to command.tcl. And I try to get it throught hyperview hierarchy, as show in the figure. I do not find what I need. I have no idea if somethig wrong. Thank you for you any advice.
23. ## get node id of *createnodesbetweennodes

O.K..It worked... Thank you so much...
24. ## get node id of *createnodesbetweennodes

Hello everyone, I want to create node in TCL, and then I use the *createnodesbetweennodes command, but I can't get the node id of the node it's created, because the result is store in reject mark, I think, but I can't access this mark. I think the hypermesh's modify command is used in display. And the query command is used to query info. I don't know if it's correct. Thank you for you any help so much..
25. ## lattice analysis using pbeaml

Hi Prakash Pagadala Thank you for your help.. I have solve this problem by updating bar2 with all upadate options.. Thank you all the same..
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