Specifying the shell parameters of a continuum shell composite layup

From the Composite Layup editor, click the Shell Parameters tab.

Specify the Section Poisson's ratio to define the shell thickness behavior:

• Toggle on Use analysis default to use the default value. In Abaqus/Standard the default value is 0.5, which will enforce incompressible behavior of the element for membrane strains. In Abaqus/Explicit the default is to base the change in thickness on the element material definition.

• Toggle on Specify value, and enter a value for the Poisson's ratio. This value must be between −1.0 and 0.5. A value of 0.0 will enforce constant shell thickness, and a negative value will result in an increase in the shell thickness in response to tensile membrane strains.

Toggle on Thickness modulus, and enter a value for the thickness modulus. If you do not enter a value, Abaqus assumes the effective thickness modulus is twice the initial in-plane shear modulus based on the material definition.

If you are specifying properties for a composite layup integrated during the analysis, select a method for defining the Temperature variation through the section:

• Choose Linear through thickness to indicate that the temperature at the reference surface and the temperature gradient or gradients through the ply are specified. You can use the Load module to specify these temperatures.

• Choose Piecewise linear over n values to enter the number of temperature points (values) through the ply in the text field provided. You can use the Load module to specify the temperature at each of these points.

Toggle on Density, and enter a value for the density. The mass of the ply includes a contribution from the density in addition to any contribution from the selected material.

For most continuum shell composite layups Abaqus calculates the transverse shear stiffness values required in the element formulation. If desired, toggle on Specify values from the Transverse Shear Stiffnesses options to include nondefault transverse shear stiffness effects in the composite layup definition, and enter values for $K_{11}$, the shear stiffness in the first direction; $K_{12}$, the coupling term in the shear stiffness; and $K_{22}$, the shear stiffness in the second direction. If either value $K_{11}$ or $K_{22}$ is omitted or given as zero, the nonzero value will be used for both. For more information, see Defining the transverse shear stiffness.