Bi-stable Steel Tape Measure Modelling in ABAQUS FEA

[Moid99]

Hi there,
I am working on a project where I have to model a bi-stable steel tape measure on ABAQUS to determine the force required to transition stable states. I need to model the snap-through behavior of a section of the bi-stable steel tape measure. See Figure 3 (a) on this Link for what the model must behave like.

I have looked at various research papers and there appears to be a common method used. The method first applies a high temperature (140°C) to simulate the curing process and cool downs to a lower temperature (20°C) while clamping the central node of the geometry. Then a point load is applied to get the stable states. I have attached the research paper who's methodology I am following. However, I am having some trouble with setting up the steps as I do not have much experience with non-linear FEA.

I am getting the following error messages:
***WARNING: ELEMENT 40 INSTANCE PART-1-1 HAS VANISHINGLY SMALL THICKNESS
(this message comes up for all elements i.e. Excessive distortion or excessive rotation of the normal in 40 shell elements)

***WARNING: EXCESSIVE DISTORTION OR EXCESSIVE ROTATION OF THE NORMAL IN 40
SHELL ELEMENTS

***NOTE: ELEMENTS ARE DISTORTING EXCESSIVELY. CONVERGENCE IS JUDGED UNLIKELY.

***ERROR: PROBLEMS HAVE OCCURRED DURING THE INITIAL STIFFNESS ASSEMBLY. THE
ANALYSIS WILL BE TERMINATED. MESSAGES DESCRIBING THE PROBLEMS ARE
REPORTED ABOVE

I don't know what these errors are referring to, nor how to resolve them.

The research paper(s) methodology that I am following are these:
Link (page 74 - 85)
Link (page 2)

I have attached my ABAQUS CAE file below.
I would appreciate if someone could help me with this problem.

Cheers,
Moid

 

[FEA way]

This model is unconstrained - there are rigid body motions left. You only fixed translations for one node in the middle of a shell part and this is not enough to run static simulation. If you perform modal analysis, you will see which motions are still possible.