# Global moment equilibrium issue with TIE connections between thickened shell meshes v2 **URL:** \ **Category:** Analysis issues\ **Created:** [November 3, 2026, 9:06pm UTC](https://calculix.discourse.group/t/global-moment-equilibrium-issue-with-tie-connections-between-thickened-shell-meshes-v2/4288 "2026-11-03T21:06:27Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![slave.k](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@slave.k](https://calculix.discourse.group/u/slave.k)\ **Post date:** [November 3, 2026, 9:06pm UTC](https://calculix.discourse.group/t/global-moment-equilibrium-issue-with-tie-connections-between-thickened-shell-meshes-v2/4288/1 "2026-11-03T21:06:27Z")
Hello everyone, As a continuation of my battle with welded steel structure described here: > [@Global moment equilibrium issue with TIE connections between thickened shell meshes](https://calculix.discourse.group/t/global-moment-equilibrium-issue-with-tie-connections-between-thickened-shell-meshes/4283): > > Hello everyone, I would like to share an observation regarding global moment equilibrium in models created using the “Thicken Shell Mesh” function in PrePoMax 3.0. While working on a relatively complex welded steel structure (approx. 60 TIEs), I noticed that the global force equilibrium was practically perfect, whereas the moment equilibrium showed significant discrepancies. After systematically removing components and constraints, I narrowed the problem down to \*TIE connections between plate… I have found additional behavior leading to global moment equilibrum discrepancy. Prepomax 3.0 + Calculix 2.22 Surface model with Thickened Shell Mesh - C3D20, 80x40x4mm Three plates connected to each other by TIE Constraint ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/7/7daef5da0b51c89c4abd8cedd455d3f388d72632.png) Vertical plates are moved 1mm out of base plate ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/e/e2b19aaab72d40909f4232aa99f7b9013450c1ef.png) There are 2 seperate tie constraints, but master is same surface in both cases, position tolerance 1mm, Adjust No ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/0/0b182f975e63772c36c43e46f8a39697e6507a2e.png) Loads - 2 separate Surface Traction, each 100N in every global direction, BC (0;0;0mm) on sidewall of horizontal plate, as shown above. Result ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/2/2e7dc0ea29d747d5815b323c9104399e1a9af35d.png) Looks correct but analysis of force and moment (in rel. to 0;0;0) equilibrum shows: ```auto FORCE [N] MOMENT [Nm] ``` RF: [-200.000065, -200.000081, -200.000007] [-12.542234, -4.259411, +20.400007] CLOAD: [+200.000000, +200.000000, +200.000000] [+16.200000, +4.200000, -20.400000] GRAV: [+0.000000, +0.000000, +0.000000] [+0.000000, +0.000000, +0.000000] DIFF: [-0.000065, -0.000081, -0.000007] **[+3.657766, -0.059411, +0.000007]** When it is connected only one vertical plate (no matter which) to horizontal plate, moment equilibrum is OK. I noticed also, that when there is only one plate connected, in analysis log there is statement like this: \*WARNING in gentiedmpc: no tied MPC generated for node **36122** no opposite master face found; in-face tolerance: 1.4240350858498002E-002 \*WARNING in gentiedmpc: no tied MPC generated for node **37120** no opposite master face found; in-face tolerance: 1.4240350858498002E-002 \*WARNING in gentiedmpc: no tied MPC generated for node **37465** no opposite master face found; in-face tolerance: 1.4240350858498002E-002 what is logical and related to 3 nodes which are out of master surface. Strange thing is that when there are 2 plates connected to horizontal one, there is no such warning at all. **Solution** Separating master for right and left plate solves the issue. Swapping master and slaves also solves issue. In that case max displacement is 1,86mm vs. 1,67 as above I can send .pmx file if needed. **Questions** : In my complete welded structure I have many big surfaces connected to small edges of other plates (area relation higher than 200:1). What is more correct/better: define Tie master surface on big area and slave on small or opposite, or it doesn’t matter? I know other rules about meshing, stiffness. ---
**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Post date:** [November 3, 2026, 11:19pm UTC](https://calculix.discourse.group/t/global-moment-equilibrium-issue-with-tie-connections-between-thickened-shell-meshes-v2/4288/2 "2026-11-03T23:19:23Z")
> [@slave.k](#): > > I can send .pmx file if needed. Could you share the .pmx and possibly also .inp file here using some hosting service ? > [@slave.k](#): > > Separating master for right and left plate solves the issue. It’s a good practice to limit the constraints and contact to minimum surfaces, but such issues may still be unexpected and require further investigation. When you share the files, I can compare it with Abaqus results. ---
**Author:** ![slave.k](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@slave.k](https://calculix.discourse.group/u/slave.k)\ **Post date:** [November 4, 2026, 7:08am UTC](https://calculix.discourse.group/t/global-moment-equilibrium-issue-with-tie-connections-between-thickened-shell-meshes-v2/4288/3 "2026-11-04T07:08:26Z")
Files are in: > **[Moment\_equilibrum](https://www.dropbox.com/scl/fo/gg2d3888qjq2qupp401d4/AMQ8HrYcuz2dKxdae68n9xY?rlkey=gau39ndwpmv1fld3kluov4iaq&st=6phg87h1&dl=0)** > > Shared with Dropbox ---
**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Post date:** [November 4, 2026, 9:05am UTC](https://calculix.discourse.group/t/global-moment-equilibrium-issue-with-tie-connections-between-thickened-shell-meshes-v2/4288/4 "2026-11-04T09:05:18Z")
Here’s what I get in Abaqus: - forces (red) and moments (blue): ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/e/e3d176b7ac92fd5a1f7dfce694357be123030d94.png) - visualization of tie constraints: ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/8/80c6e9a6ea02dbc95988ed82f2ef46500a9bf8ff.png) - displacements: ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/f/f58519f2334a50ace5eb2aa96757315b5d73f703.png) ---
**Author:** ![Stefano4000](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@Stefano4000](https://calculix.discourse.group/u/Stefano4000)\ **Post date:** [November 4, 2026, 2:37pm UTC](https://calculix.discourse.group/t/global-moment-equilibrium-issue-with-tie-connections-between-thickened-shell-meshes-v2/4288/5 "2026-11-04T14:37:19Z")
Calculated here with 2.22, better is here basically actual version 2.23 to go not in solved problems. Is here a fast calculation here possible? Same results in 2.22 and 2.23?