Seam Hexa Adhesives

The Seam Hexa Adhesives realization creates a continuous or discontinuous hexa weld with a predefined pattern.

All defined information is stored on the connector, and can be exported into the connector .xml file.


Figure 1. Seam Hexa Adhesives

Seam Hexas are created from the Seam panel.

The HEXA elements will be centered about the seam connector if the seam connector is not close to a free edge. If the distance between the seam connector and free edge of a component is less than half the width of the HEXA, then the realization of HEXA elements will start from the seam connector and will be extruded in the direction away from the edge.


Figure 2.

For OptiStruct and Nastran solvers, the HEXA elements are tied to a shell using RBE3’s at locations where the HEXA nodes and shell nodes are non-coincident. If the HEXA nodes and shell nodes are coincident then RBE2's will be used to tie them.

For the LS-DYNA solver only, the shell gap thickness option is supported. If the HEXA nodes are coincident with shell nodes, then those shell nodes will be used to create HEXA elements. The HEXA elements at some or all nodes will be tied directly to the shells.

This realization type is intended to work on meshes, both shells and solids.

The hexa dimension depends on the following settings:
  • The length of a hexa is predefined by the distribution of the test points along the seam connector. This is defined by spacing or density during the connector creation.
  • The width of the single hexa depends on the number of strips and the defined total width of the seam, which is measured perpendicular to the seam direction.
  • The thickness of a single hexa depends on the number of defined coats and the selected thickness option.
The available thickness options interact with the consider shell thickness option and offset for hexa positioning option. In the figures below, the green seams on the left take into account the thickness as well as the shell offset. This information is used for dimensioning and positioning the hexas. For the pink seams on the right side, the hexas are always positioned around the exact middle between the current shell positions. The shell thicknesses are taken into account only for the hexa height, but not for the positioning. The orange lines and arrows in the figures below illustrate the dependencies for the positioning.
shell gap
The seam completely and exactly fills the gap between the two shells. Shell thicknesses and offsets are not considered.


Figure 3. Shell Gap
maintain gap
The seam is positioned in the exact middle between the shells. The seam thickness is adjusted, that on both sides the gap between shell and seam fits the defined gap size. Shell thicknesses and offsets are not considered.


Figure 4. Maintain Gap
(t1+t2)/2
The seam thickness is calculated by averaging both shell thicknesses. On the left side the offsets and thicknesses are taken into account, so that the seam is positioned around the middle of the air gap. On the right side the seam is just positioned around the middle of the shell positions.


Figure 5. (t1+t2)/2
midthickness
On the left side the exact air gap is determined and filled with the seam. On the right side the seam thickness is calculated by subtracting half the thickness of both shells from the total distance of the shells.


Figure 6. Midthickness
const. thickness
The thickness of the seam is predefined for both; on the left side the seam is positioned around the middle of the air gap, on the right side around the middle of the two shells.


Figure 7. Const. Thickness