Map Mid-Mesh Thickness Tool

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HyperMesh and BatchMesher

Map Mid-Mesh Thickness Tool

Use the Map Mid-Mesh Thickness tool to calculate the thickness of a mid-mesh from the solid

geometry. The thickness will be assigned on the mid-mesh either on node card, element card, nodal thickness on element card or also as properties on elements depending on the user profile you are using. You can access the Mid-Mesh Thickness tool by clicking Mesh > Edit > Elements >

Midmesh Thickness from the menu bar when the OptiStruct, RADIOSS, Abaqus, LS-DYNA, or Nastran user profiles are loaded.

The Map Mid-Mesh Thickness tool is divided into the following sections:

Input

The mid-mesh and solid can be specified by selecting entities in the HyperMesh session

interactively, or optionally, external geometry or FE solver decks can also be selected as input.

FE and Geometry displayed Traditional Element Visualization

Thickness Output

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The following options are available from the Thickness Output section:

Thickness Output:

Select one of the following thickness output options:

Output Description User Profile

Node Assigns a thickness on node cards. Abaqus

Element Assigns a single thickness on element card.

RADIOSS, Abaqus, LS-DYNA (SHELL card image)

Nodal Thickness on Elements

Assigns multiple thicknesses on elements for each node.

OptiStruct, LS-DYNA, Nastran

Properties on Elements

Creates properties for groups of elements, and assigns a thickness to each property.

OptiStruct, Nastran, Abaqus

Properties on Components

Creates components and properties for groups of elements, assigns a thickness to each property, and then assigns the property to a component.

LS-DYNA

Select Card Image Assigns a thickness on INISHE entities, when you select one of the following card images from the list:

SHELL, EPESP_F, STRA_F, and STRS_F.

RADIOSS

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Any calculated thickness below the specified value will be reset to the specified minimum value.

Maximum Thickness: (Optional)

Any calculated thickness above the specified value will be reset to the specified maximum value.

Assign offset to elements:

If set, the offset value will be assigned on the element cards.

Note that the mesh deviates from the geometry; the mid-mesh node is equidistant from mesh corners, but not from the nodes on the geometry corners.

- 2D Detailed Element Representation is active - No Element Offset is active

Here, the offset has caused the mesh to match the geometry, though the initial mid-mesh node remains unchanged.

such that it now matches the geometry.

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Assign average thickness to element groups:

This option is available when the thickness output option is Elements. By setting this option, the thickness values on individual elements will be approximated to be an average value

representing a group of elements.

Maximum Thickness Range Interval:

This option is available when the thickness output option is Properties on elements or when the Assign average thickness to element groups check box is selected.

Use this option to control the number of thickness properties or groups. Setting this ensures that no thickness group or property will have a thickness interval range greater than the specified value. In other words it is the maximum limit on the max thickness – min thickness in a thickness group or property.

Truncate Thickness to Range Interval

This option is only available when the Maximum Thickness Range Interval check box is selected. By selecting this option, the thickness values will be rounded up or down to have the same number of decimal digits as the input value in the Maximum thickness range interval field.

Correction Method:

On elements or nodes where the thickness could not be computed correctly, there are different options to correct it:

• Interpolate from Neighbors: An appropriate thickness value is interpolated from the neighboring element/node thickness.

• Adjust to min/max values: If either minimum or maximum thickness is defined it is assigned on the corrected elements.

Scaling at corners:

This option is available only when the Correction method is set to Interpolate from Neighbors. When interpolating thickness values near t-junctions or corners, a scaling algorithm is applied:

• Supplying a value less than 1 will result in linear decrease in the thickness values nearer to the junctions / corners.

• A value of zero will result in an approximate mass-conserved thickness estimation.

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Scaling at corners = 0 Thickness Contour Applied Traditional Element Visualization

Scaling at corners = 0 Thickness Contour Applied

2D Detailed Element Representation

If this is equal to 1, the thickness is extrapolated / interpolated without any scaling.

Scaling at corners = 1 Thickness Contour Applied Traditional Element Visualization

Scaling at corners = 1 Thickness Contour Applied

If this is greater than 1, the thickness will increase as you go closer to the junction.

Max Midmesh/Solid Angle (0,90):

This is the maximum angle (0 to 90) that the mid-mesh makes with the solid, beyond which the estimated thickness will be ignored and corrected.

Max Thickness Gradient (0, 10):

This is the maximum change in thickness allowed across two adjacent measurement locations, as a factor of the distance between the locations. Allowable factors range from 0 to 10.

Max search distance:

Use this option to specify the maximum distance which will be considered for searching solid proximity. This value is also used to restrict the maximum distance from which a good

thickness value is considered for correcting an incorrect thickness estimate. You can also used this option to restrict the algorithm from assigning incorrect thicknesses for the mid-mesh that is out of the solid proximity.

Do not assign thickness to Mid-mesh outside solid

When this option is enabled, a thickness will not be assigned to the Mid-mesh outside of the solid.

Save log file:

The information logged during the computation can be directed the supplied file.

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Clicking the Calculate Thickness button will begin the operation. The thickness will be computed and assigned on the mid-mesh.

View

In the View section, there are several options for visualization:

Element Coloring by thickness:

HyperMesh Element Color mode will be set to ‘By Thickness’ resulting in contour plot of thickness.

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Thickness Contour Applied

2D Detailed Element Representation:

The mid-mesh elements will be visualized as 2D with the assigned thickness as depth.

Assigning a thickness for each individual Node or element, allows you to assign a variable thickness to elements. You can visualize both the element and nodal thickness in the graphics area by selecting the 2D Detailed Element Representation option from the Visualization toolbar.

The behavior of the 2D Detailed Element Representation option depends on what you assigned a thickness to. For example, if you assign a component an element thickness, then the element thickness representation will be displayed. If you assign a nodal thickness to an element node, then each individual node thickness will be plotted and you will be able to see the first and second order trias and quad elements. When you assign a nodal thickness, you can select the By Thickness option in the Visualization toolbar to display each node value. If you assign a nodal thickness, and the offset option is on, then the element thickness from the nodes will be calculated, the element will be offset, and the nodal thickness 2D Detailed Element

representation on the offset elements will be plotted.

Limitations

Currently, composites with variable thickness are not added for this new feature.

Highlight Corrected Elements:

The elements are highlighted whereby the thickness could not be calculated from solid, and the correction method has been deployed.

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2D Detailed Element Representation Corrected Elements Highlighted