# Contact\_Primary model and Secondary model **URL:** \ **Category:** General Questions\ **Tags:** results\ **Created:** [January 3, 2024, 12:29am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382 "2024-01-03T00:29:37Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 3, 2024, 12:29am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/1 "2024-01-03T00:29:37Z")
Dear Sir, Regarding the presentation in the below, the model interest is the Bracket which shown and display the mises stress, however in case the model interest is the tube, how to set the parameter, so that I can determine how much stress for the tubes. Summary: How to set the parameter for primary model and secondary model? Primary model: Able to display the Von mises stress, displacement, etc. Secondary model: is just load distributor only. [PrePoMax & CalculiX - GUI Contact (youtube.com)](https://www.youtube.com/watch?v=AaeLSLotwi0&t=181s) Thank you for your kind support. Best Regards jess ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [January 3, 2024, 7:52am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/2 "2024-01-03T07:52:59Z")
In this analysis both parts are deformable so you can check their stresses. However, you could also make one part (the one for which you don’t need the stresses) rigid using a rigid body constraint: [How to treat a body as rigid?](https://prepomax.discourse.group/t/how-to-treat-a-body-as-rigid/1279) ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 5, 2024, 11:08pm UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/3 "2024-01-05T23:08:13Z")
Dear Sir, Regarding implementation of Rigid Body, yellow line is existing rigid body (this is doable as it is available already in Prepomax). However, is it possible to connect all 3-reference point connected by another Rigid body element (red line)? I need to provide upper rigid body to consider the load moment distance. Please see attached snap shot ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/8/8e18c84fe2f2037f325e882beca2bfad3384a932.jpeg) Thank you sir and appreciate for your kind help. ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [January 6, 2024, 12:17am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/4 "2024-01-06T00:17:24Z")
Try this way: [Rigid bodies connected.pmx](https://prepomax.discourse.group/uploads/short-url/ua1aerAoWCpPLFetQkj8kQ9n55j.pmx) (1.3 MB) ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 1:40am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/5 "2024-01-06T01:40:21Z")
Dear Sir, thank you so much that’s brilliant idea 😍. Now I understand that reference point is not just a point, but it actually mimic a rigid body element where able to transfer the load, even it is not connected directly to the model or another rigid body element. Thank you always sharing your brilliant ideas. ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 9:22am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/6 "2024-01-06T09:22:50Z")
Dear Sir, I apply in the model I created; however I cannot find any reason why in my model does not run and warning message occur. I did my trial in the model you send and it works very well. But in my model Job failed-no results exist. ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/1d078ac83350e123b4cfb83c72f8c11cd0e41681.png) Do I need to apply sub modeling since I divide the model into 2. This is because I have load on left side and right side, in addition to the load moment at upper side Fz? Kindly see the attached model for your details of my model in the following message. Thank you and really appreciate for your kind help. ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [January 6, 2024, 9:51am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/7 "2024-01-06T09:51:27Z")
Can you share your .pmx file ? ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 10:01am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/8 "2024-01-06T10:01:31Z")
Sorry I am trying to compress the file but still more than 8MB. ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/0/0f09c333716e738a5229831c75d2002501da9350.png) ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 10:04am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/9 "2024-01-06T10:04:27Z")
Sir, Is there any way how I can share my file more than 8MB other than zip file. Any link I can use? Thank you appreciate any advice, ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [January 6, 2024, 10:16am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/10 "2024-01-06T10:16:37Z")
You can upload it to some hosting website like WeTransfer, Google Drive or Dropbox and paste the link here. ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 10:20am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/11 "2024-01-06T10:20:06Z")
Ok sir, thank you for your kind advice I will do that. For the mean time Sir I just make my mesh using BASIC and not use ADVANCED setting. Then my file is become small. See attached file sir. [3D\_LUG\_CUT-Mid\_Static\_SmallFile.pmx](https://prepomax.discourse.group/uploads/short-url/pzhGbB7yBVMDMN3qoYBpUMwZebU.pmx) (314.3 KB) ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 10:49am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/12 "2024-01-06T10:49:52Z")
Dear Sir, regarding the Rigid Body Element, for my reference and comparison I made a model where the actual pin is model. My purpose is to compare the result of Rigid Body Element result to actual 3D solid model so that I have further analysis. Therefore in this case I use contact. After run the basic analysis there is very big difference for Von mises stress. Appreciate sir any helpful advise. Kindly see the attached model. [3D\_LUG\_Contact.pmx](https://prepomax.discourse.group/uploads/short-url/aoCPe9r77XkKKqhkbpX0E3izvMP.pmx) (540.0 KB) Thank you and really appreciate for your kind help. ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 11:03am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/13 "2024-01-06T11:03:16Z")
> [@jsarocena](#): > > I did my trial in the model you send and it works very well. But in my model Job failed-no results exist. **Sir I would like to Update my query:** Apologized. After reducing the mesh size, successfully got the results. No job failed. **Updated query:** 1. RIGID Body: Do I need to apply sub modelling to avoid separation ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/3/3ac903334d3ef839aa7ac846abdc930c4ce6c5ba.png) 2. Rigid Body vs Contact: Rigid Body: 1089MPa Contact: 7820 MPa There are 7.18 x difference. Appreciate any advice. Thank you so much. ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [January 6, 2024, 12:13pm UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/14 "2024-01-06T12:13:52Z")
Contact requires very dense (locally) meshes to provide accurate results. This mesh is way too coarse. Check e.g. this tutorial: [https://www.youtube.com/watch?v=pEktnro0G0k](https://www.youtube.com/watch?v=pEktnro0G0k) To simplify the analysis in which the pin is modeled, you could make it rigid (by applying a rigid body constraint to it). That would be something between the case with a deformable pin and with only rigid body constraints replacing it. Another way would be to model the pin as a rigid surface (shell) and connect a rigid body constraint to it to provide this arm for loading. The case with only rigid body constraints might be too simplified to provide good results. Especially since the actual pin doesn’t pull the bottom part of the hole (you could split it for rigid body constraints or use the compression-only constraint). Also, you need some interaction (tie or contact) between the two parts of the lug in the case without contact. As you can see in the screenshot you attached, there’s an interference and separation between the parts. ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 6, 2024, 4:22pm UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/15 "2024-01-06T16:22:48Z")
> [@FEAnalyst](#): > > Another way would be to model the pin as a rigid surface (shell) and connect a rigid body constraint to it to provide this arm for loading. Dear Sir, I try hard to visualize this, however I cannot, appreciate if you could give me a hint like a simple sketch only will be very helpful. Thaks a lot. ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [January 6, 2024, 4:56pm UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/16 "2024-01-06T16:56:51Z")
Something like this: ![shell](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/7/7c041730302409f6b6d00bd9f7121af86d26c9d4.jpeg) But the shell should be rigid (either using rigid body constraint or large Young’s modulus). ![shell 2](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/7/7ed36d59ed2006600ff972d727dbb6fb16226f52.jpeg) ---
**Author:** ![TKemeny86](https://avatars.discourse-cdn.com/v4/letter/t/58f4c7/32.png) [@TKemeny86](https://prepomax.discourse.group/u/TKemeny86)\ **Post date:** [January 6, 2024, 6:22pm UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/17 "2024-01-06T18:22:50Z")
Try non-linear analysis. In this case, deformation can be large, therefore the stress to. With material non-linearity, the large deformation won’t cause large stress values ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 7, 2024, 12:25am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/18 "2024-01-07T00:25:49Z")
> [@FEAnalyst](#): > > Something like this: Thank you Sir @FEAnalyst . I appreciate sharing your ideas, beyond your technical expertise Sir, I just want to thank you for being such a generous and supportive mentor in the FEA world. Your willingness to answer my questions and share your knowledge has been invaluable. I am gaining and feel much more encouraged and not give up in the FEA world i.e. tackling complex analyses if there is someone in the community like you. Thanks to you. ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 7, 2024, 1:00am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/19 "2024-01-07T01:00:44Z")
> [@TKemeny86](#): > > Try non-linear analysis Thank you Sir @TKemeny86 , I will also try your suggestion doing material non-linearity. ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 7, 2024, 3:39am UTC](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382/20 "2024-01-07T03:39:53Z")
> [@FEAnalyst](#): > > Try this way: > > [Rigid bodies connected.pmx](https://prepomax.discourse.group/uploads/short-url/ua1aerAoWCpPLFetQkj8kQ9n55j.pmx) (1.3 MB) Dear Sir @FEAnalyst , Sorry I came back here. I miss very important question in your model. Would I know how did you connect the upper reference point since there is no Rigid Body assigned? Thanks… ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/d/d9fc019c88f175819bd80ac7709bde3156a97912.png) [Next page](https://prepomax.discourse.group/t/contact-primary-model-and-secondary-model/1382.md?page=2)