# Unusual results with tie constraint **URL:** \ **Category:** General Questions\ **Created:** [May 7, 2025, 3:22pm UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681 "2025-05-07T15:22:42Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Rishabh](https://avatars.discourse-cdn.com/v4/letter/r/ea5d25/32.png) [@Rishabh](https://prepomax.discourse.group/u/Rishabh)\ **Post date:** [May 7, 2025, 3:22pm UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/1 "2025-05-07T15:22:42Z")
Hello I am doing a static analysis where I apply gravity load on my assembly. The problem I have encountered is with tie constraints. As you can see from the picture that the marked parts are tied with eachother with sufficient search distance to form tie constraint ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/9/907b24913c5f63e3bd6b891a3391114162f931bb.png) Still, when I look at the displacement contors, the tied regions look like to have relative displacement between each other. ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/b/b4af5ba880d9e55483a6c15c4062d5dfb29810f4.png) It does not make sense to me. Shouldn’t the tied regions show same displacment contors ? Here is the file > **[20250507\_E-cruiser\_sliding\_battery.pmx](https://wetransfer.com/downloads/c47063e9eb31a56da0144d6fb9838ebb20250507150014/47a162?t_exp=1746889214&t_lsid=543d2415-becb-4d2e-892d-217ffb51f1a7&t_network=link&t_rid=Z29vZ2xlLW9hdXRoMnwxMTI4MjI3MDUwMTIyMzgwMzYwNTc=&t_s=download_link&t_ts=1746630014)** > > 1 file sent via WeTransfer, the simplest way to send your files around the world can anyone please help me identify the error Thank you in advance ---
**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:** [May 7, 2025, 4:43pm UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/2 "2025-05-07T16:43:55Z")
You can easily check if tie constraints work properly by running a frequency analysis. If anything is disconnected, it will be visible in low frequency modes. ---
**Author:** ![Rishabh](https://avatars.discourse-cdn.com/v4/letter/r/ea5d25/32.png) [@Rishabh](https://prepomax.discourse.group/u/Rishabh)\ **Post date:** [May 7, 2025, 6:55pm UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/3 "2025-05-07T18:55:17Z")
Thank you for the suggestion. My first mode starts at 50.65 Hz. I will not see any rigid body motion as my side plates are properly connected to the bottom frame. I still have the doubt that something is wrong as I see the maximum deformation in the plate where I suspect that tied constrain is not working there properly ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/d/d20cbe9e12003e79d61f353c8dafaf2ccb241988.png) ---
**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:** [May 7, 2025, 7:14pm UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/4 "2025-05-07T19:14:43Z")
What if you animate the mode shapes ? The displacement values in frequency analyses are unphysical but deformed mode shapes can be very helpful. You could also check the warning messages about nodes involved in tie constraints. ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [May 8, 2025, 6:28am UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/5 "2025-05-08T06:28:04Z")
Your constraint is not working. If you use Automatic scaling of the results, you will be able to see it. ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/f/f862c015bd9537fffe4c6b693cf3e8d2eb7e17e6.png) In CalculiX, one surface must not be a master surface (red) in a tied constraint more than once. You have constraints part-81\_to\_part-49 and part-81\_to\_part-41, which violate this principle. You should merge such constraints into one (select both, right click, merge). ---
**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:** [May 8, 2025, 8:15am UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/6 "2025-05-08T08:15:46Z")
I couldn’t check the file yesterday but right, that’s also why there’s a bunch of warning messages such as: ```auto *WARNING in gentiedmpc: DOF 1 of node 168558 is not active; no tied constraint is generated *WARNING in gentiedmpc: DOF 2 of node 168558 is not active; no tied constraint is generated *WARNING in gentiedmpc: DOF 3 of node 168558 is not active; no tied constraint is generated ``` ---
**Author:** ![Rishabh](https://avatars.discourse-cdn.com/v4/letter/r/ea5d25/32.png) [@Rishabh](https://prepomax.discourse.group/u/Rishabh)\ **Post date:** [May 8, 2025, 10:06am UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/7 "2025-05-08T10:06:06Z")
Thank you so much. I really didn’t know this. I will try to correct it ---
**Author:** ![Rishabh](https://avatars.discourse-cdn.com/v4/letter/r/ea5d25/32.png) [@Rishabh](https://prepomax.discourse.group/u/Rishabh)\ **Post date:** [May 8, 2025, 3:42pm UTC](https://prepomax.discourse.group/t/unusual-results-with-tie-constraint/2681/8 "2025-05-08T15:42:09Z")
I tried your suggestion @Matej, also thank you @FEAnalyst. My problem has been solved ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/143455a2d783505c2fedc5d3a4dbe7657cce4ed0.png)