Note: The area section thickness and joint offset overwrite assignments do not apply to layered shells.
Use the Shell Section Layer Definition form to define a layered shell object.
Quick Start button. Click this button to display the Concrete Shell Section Quick Start Parameters form. Use the form to specify rebar material and size for a single layer or the top and bottom of a two-layer concrete shell object. After the parameters have been specified on that form, the data will transfer automatically to the spreadsheet area on this form (i.e., the cells for the Layer Name, Distance, Thickness, Material, and so forth on the Shell Section Layer Definition form will be filled automatically). Modification to the parameters can be made by direct entry into the appropriate cell, as described below.
Layer Name edit box. Use the default or type a revised label for the name of the layer (e.g., 1, 2, 3 or Top, Middle, Bottom).
Distance edit box. Enter a value for the distance from the shell reference surface (shell object joint location plus offsets) to the mid-height of the layer. Positive distances are in the positive shell object local 3 axis direction
Thickness edit box. Use this edit box to specify the thickness of the layer. Note that the thickness of the section depends on the thickness specified for each layer (i.e., this value) and any overlaps or gaps between the layers. Thus, the section thickness is the value calculated by the program using all of the entries made in this column for each layer of the section.
Type drop-down list. Use the drop-down list to select the behavior for each layer. Select Membrane to model only in-plane behavior, Plate to model only out-of-plane bending behavior, and Shell to model full shell behavior.
Num Int. Points edit box. Use the default or specify a revised number of integration points in the thickness direction for the layer. The locations are determined by the program using standard Gauss-quadrature rules.
Material drop-down list. Use the drop-down list to select the material type for each layer. Each material type will be given a unique color in the display area in the lower left corner of the form.
Material Angle edit box. If appropriate, specify the material angle for the layer definition. The angle is measured counterclockwise from the local 1 axis of the shell object to the local 1 axis of the material.
Material Component Behavior:
Type drop-down list: Use the drop-down list to select the material component behavior type: Directional may be chosen for any material property, Coupled is available if coupled nonlinear data is available for the specified material property (see: Material Property Options Form). When Directional is selected, the behavior of the nonlinear components is determined from the material’s uniaxial nonlinear data and each component is independent from the others. When Coupled is selected, all three membrane stress components (S11, S22, and S12) will be nonlinear and their behavior is determined from the material’s coupled nonlinear data.
S11, S22, and S12 drop-down lists: When Directional is chosen in the Type drop-down list, choose Linear, Nonlinear, or Inactive from the drop-down list for each component. When any of the components is set to be Linear, the layer will behave linearly in that direction in a nonlinear load case. When any of the components is set to be Nonlinear, the layer will behave nonlinearly in that direction in a nonlinear load case. When any of the components is set to Inactive, the layer will not contribute to the stiffness in that direction in a nonlinear load case. When Coupled is chosen in the Type drop-down list, all components will be set to Nonlinear.
Note: When Directional is chosen in the Type drop-down list, the Poisson's ratio will be taken as zero in a nonlinear load case, regardless of the value defined in the material property, unless all three material components are linear.
Note: Regardless of the selected behavior, all three material components will behave linearly in a linear load case.
Up and Down buttons. When multiple rows of data have been specified, use these buttons to move quickly through the spreadsheet area of the form.
Add, Insert, Modify, and Delete buttons. Use these buttons to manage the rows of data in the spreadsheet area.
Enter text or numbers in the Layer Name edit box, values in the Distance, Thickness, Material Angle or Num Intg Points edit boxes or make a selection in the Material or Nonlinear drop-down lists and then click the Add button to add that row of data to the definition.
Enter text or numbers in the Layer Name edit box, values in the Distance, Thickness, Material Angle or Num Intg Points edit boxes or make a selection in the Material or Nonlinear drop-down lists and then click the Insert button to insert that row of data between two existing rows of data in the definition.
Make a change in the Layer Name, Distance, Thickness, Material Angle or Num Intg Points edit boxes or the Material or Nonlinear drop-down list and then click the Modify button to change that row of data.
Highlight a row of data and click the Delete button to remove it from the definition.
Highlight Selected Layer check box. When this check box is checked, the layer selected/highlighted in the spreadsheet area will be shown in the display area with an outline in a darker hue of the Material display color.
Transparency Control slide bar. The slide bar can be used to increase or decrease the transparency of the layers shown in the Display area. This slide bar is inactive when the Highlight Selected Layer check box is checked.
Display area. A simple drawing of the orientation of the layer(s) relative to the shell reference surface (i.e., the red line shown in the display area) is displayed here.
Section Name display box. This is the label given to the area section property on the Shell Section Data form.
Order Ascending button and Order Descending button. Click these buttons to reorder the rows of data in the spreadsheet area according to the values in the Distance column.
Calculated Layer Information area. The Number of Layers, Total Section Thickness, Sum of Layer Overlaps and Sum of Gaps Between Layers display boxes in this area of the form are informational and cannot be edited directly. The program displays information in these display boxes using the entries in other portions of the form.
Access the Shell Section Layer Definition form as follows:
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