Hinge Interconnection Not Working – Only One Shell Part Moves

[adi@1234]

Hi everyone,


I’m working on modeling a bistable mechanism in Abaqus and am having trouble getting the hinge interconnection to work correctly.


Problem Summary:
When I run the simulation, only one of the shell parts moves while the other stays fixed, even though I have defined the hinge connection between them.


Setup Details:

• Element Type: S4R shell elements
• Geometry: 3D deformable planar shells
• Steps: Static General
• Assembly Workflow:
  
  • Created datum points and converted them into reference points
  • Translated and rotated the shell parts into position
  • In the Interconnect module, created a line element connecting the reference points and assigned a hinge interconnection
  • Specified a local coordinate system with the X-axis as the free rotation axis

Boundary Conditions:

• Initial step: Fixed side parts with U1 = U2 = U3 = 0
• Static General step: Applied displacement boundary condition to the middle part to induce deformation

Issue:
When the simulation runs, the moving part responds to the load, but the second part remains stationary, as if the hinge connection is not actually linking them.


Image:
Below is a screenshot of the assembly setup:








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Request:
Could anyone please advise:

• How to correctly define the hinge interconnection so that both shell parts move together?
• Are there specific checks or constraints needed to ensure the connectivity is enforced during simulation?

Any help or suggestions would be greatly appreciated.

 

[FEA way]

Did you attach those reference points to the plates ? You can do that via rigid body or coupling constraint.

 

[adi@1234]

Hello,
Thank you for replying

• I created two separate reference points, each positioned slightly offset from the center of their respective shell parts.
• I applied coupling constraints so that each reference point is attached to its own shell part (not cross-coupled).(used local coordinate system and gave hinge axis degree of freedom)
• I first used Kinematic coupling, then also tried Distributing coupling to see if this would allow deformation.
• The hinge connector was defined between the two reference points, with a local coordinate system (X axis as free rotation).
• The shells have U1=U2=U3 fixed at the ends, and displacement was applied to the middle area.

After these steps, one of the shell parts still does not move, and in the results there is almost no deformation or stress in that part.
Sometimes neither plate moves at all, and sometimes only one plate moves while the other stays fixed.
Any further ideas on what might be causing this or what else I should check?

 

[adi@1234]

Did you attach those reference points to the plates ? You can do that via rigid body or coupling constraint.

Hello,
Thank you for replying

• I created two separate reference points, each positioned slightly offset from the center of their respective shell parts.
• I applied coupling constraints so that each reference point is attached to its own shell part (not cross-coupled).(used local coordinate system and gave hinge axis degree of freedom)
• I first used Kinematic coupling, then also tried Distributing coupling to see if this would allow deformation.
• The hinge connector was defined between the two reference points, with a local coordinate system (X axis as free rotation).
• The shells have U1=U2=U3 fixed at the ends, and displacement was applied to the middle area.

After these steps, one of the shell parts still does not move, and in the results there is almost no deformation or stress in that part.
Sometimes neither plate moves at all, and sometimes only one plate moves while the other stays fixed.
Any further ideas on what might be causing this or what else I should check?

 

[FEA way]

Try with edges selected for coupling constraints instead of the whole plates.