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Showing posts with label Mindlin-Reissner. Show all posts
Showing posts with label Mindlin-Reissner. Show all posts

October 18, 2013

Thin Shell vs. Thick Shell

Thick shells are capable of modelling transverse shear deformation whilst thin shells do not. Thick shells are governed by the Mindlin–Reissner (thick shell) theory. As the shell thickness decreases, the problem tends to favour Kirchhoff (thin shell) theory which neglect the inclusion of transverse shear deformation. This is pretty much similar to the thin (Euler-Bernoulli) vs. thick (Timoshenko) beams comparison.

     Typical thickness for thin shell is <5% whilst thick shell theory applies within the 5-10% range. Anything significantly >10% should not be modelled using plate theories.

A comparison of the differences between thin and thick shell theories.
Theory Thin shell
Kirchoff-Love
Thick shell
Mindlin-Reissner
Thickness vs. percentage of in-plane dimensions Thickness < 5% 5% < thickness < 10%
Key assumptions • Plane remains plane
• Normal remains normal
• Thickness is not affected by deformation
• Plane remains plane
Degree of freedom per node • Translations Ux, Uy, Uz
• Rotations Rx, Ry, Rz
• Translations Ux, Uy, Uz
• Rotations Rx, Ry, Rz
Transverse shear deformation No Yes

See also
Types of elements in the element library