hexa nugget

Use the hexa nugget realization to create hexa clusters between shell components.

Contacts are defined between the shell components and the appropriate hexa nodes. A heat affected zone for the shells from ultra-high strength steel material is also created.

Hexa Nugget realizations can be used for any amount of parallel combinations of shell components.

Define the heat affected zone dimensions using the parameters available in the Connector Entity Editor. The dimension and property of each heat affected zone (HAZ) can be separately defined. Each setting is stored and considered per individual connector.

General Info

Table 1.
Parameter	Action
Tolerance	Specify a distance from the connector location. Only the entities within this tolerance can be taken into account for the final realization. The tolerance is used to verify whether adequate link candidates are available to be connected with respect to the number of layers.

Weld Shape

Table 2.
Parameter	Action
Hexa Number	Create a hexa cluster of 4 hexas, arranged in a predefined pattern. Note: By default, Hexa Number is set to 4 hexa. You cannot edit this field.
Coats	Specify the number of hexa elements required along the thickness. Note: By default, Hexa Coats is set to 1 for a hexa nugget connector. You cannot edit this field.

Realization Details

Use the Realization Detail parameters to define the dimension of the welds.

Table 3.
Parameter	Action
Diameter Option	Choose how the diameter is defined. This field is used for realizations based on hexa elements, where the size of the realized element (hexa) is created based on the diameter value. diameter Specify a single diameter value. diameter mapping file Use a diameter mapping file to calculate the diameter. The diameter mapping file obtains diameter values that you assigned to a range of flange thicknesses in the Diameter Table. Along with flange thickness ranges, you can also specify the main flange thicknesses to consider when assigning diameter values.
Hexa Thickness Option	Project the hexa spot to touch the shell elements. The position is independent from any thickness. Note: By default, Hexa Thickness Option is set to shell gap. You cannot edit this field.

Connectivity Info

Table 4.
Parameter	Option
Connectivity	Note: By default, Connectivity is set to contact, but you can also choose imprint.
HAZ	Create the quad weld elements and stitch them to both links by adjusting their mesh. Perform all required HAZ.
Enable Condition HAZ	Control which parts need to receive heat affected zones during the realization.
Skip Imprint	Create the quad weld elements, but do not change the meshes of the links. Instead, create additional elements to represent the requested HAZ. These elements are organized in the ^conn_imprint component. You can use these elements for a later manual imprint after they have been manipulated to your need. This can be helpful in more complex areas, where the standard imprint functionality fails, for example, when working with conflicting connectors. Note: The quad weld elements are not attached to the links. The connection needs further attention.

Contact Info

Table 5.
Parameter	Action
Contact Creation Option	Choose a method for creating contacts. one contact per link Create one exclusive contact with two exclusive sets per each link. Create the contact between the link and the hexa nugget nodes laying on this link. The nodes of one hexa nugget belong to two different contact definitions. Groupname(s): hexa_nugget_contact_Linkname Setname(s) Main: hexa_nugget_master_part_set_Linkname Setname(s) Secondary: hexa_nugget_secondary_node_set_Linkname one contact per link pairing All hexa nugget connectors using the same links are sharing the same contact and sets. Groupname(s): hexa_nugget_contact_Linkname1_Linknam e2_Linkname3(when 3 layer) Setname(s) Main: hexa_nugget_main_part_set_Linkname1_ Linkname2_Linkname3 Setname(s) Secondary: hexa_nugget_secondary_node_set_Linkname1_L inkname2_Linkname3 single contact Create one contact and two sets for this realization type in the model. Groupname: hexa_nugget_singlecontact Setname Main: hexa_nugget_single_main_part_set Setname Secondary: hexa_nugget_single_secondary_node_set

Auto Correction

Table 6.
Parameter	Option
Allow Reposition	Reposition hexa elements and HAZ elements. If the option is deselected, the connector will fail when the connector is too close to free or feature edges where the nugget and HAZ elements cannot be accommodated.
Reposition Tolerance	Specify a maximum allowable distance by which hexa elements and HAZ elements are repositioned based on connector location to edge.
Control Distance	Choose a method for controlling distance. for close free edges Only consider the connectors which are positioned close to free edges for repositioning at the time of realization. for close free and feature edges Only consider connectors for repositioning at the time of realization which are positioned close to free edges as well as feature edges.
Requested Distance	Choose whether the distance to reposition is based on minimum distance to imprint or a minimum distance to connector projection.
Distance	Choose whether to manually specify a distance or use the minimum element size from the element criteria file.

HAZ Info

Table 7.
Parameter	Option
HAZ Material Condition	Enable the selection of UHSS material which controls which parts need to receive heat affected zones during the realization.
UHSS Material Option	Choose a method for selecting UHSS material. From current model Select an existing material from current model. In the Connector Entity Editor, the UHSS Material Entity ID’s field is populated with the number of the materials selected. From search file (default) Select material from a search file. For Hexa Nugget Connector realizations the material search file name is materialsnippets.txt. HyperMesh searches for this file in the following locations and in the following order: Installation: [hm_scripts_dir]/ connectors/materialsnippets.txt User directory: [USER_HOME]/ materialsnippets.txt HyperMesh configuration path folder: [HW_CONFIG_PATH]/materialsnippets.txt Current working folder: [CURRENTWORKINGDIR]/materialsnippets.txt In the Connector Entity Editor, the UHSS Material File field is populated with the name of the file that was found last. The text file contains snippets from the material names, which need to receive heat affected zones during the realization. From connector metadata Once a connector is realized with the UHSS Material Option “From search file”, the folder name is written as metadata to the connector in a relative manner to allow the exact same rerealization in a different work environment as long as the same materialsnippets.txt files are saved in according folders.
HAZ Dimension Scheme	Choose a setting for defining HAZ diameters.
HAZ Inner Diameter	values Specify an absolute value for the HAZ Inner Diameter. Note: This value must be greater than the value used for defining the nugget diameter. scale factors Calculated as a scale factor from the nugget diameter. Note: This value must be greater than or equal to 1.0. offsets Specify a HAZ Inner Diameter which is offset from the nugget diameter.
HAZ Outer Diameter	values Specify an absolute value for the width of the first layer around the HAZ Inner Diameter. scale factors Specify a width for the first layer around the HAZ Inner Diameter. Calculated as a scale factor from the nugget diameter. offsets Specify a width for the first layer around the HAZ Inner Diameter which is offset from the HAZ Inner Diameter. Note: For values and scale factors, this value must be greater than the value used for defining the HAZ Inner Diameter.
HAZ Layer 2	Enables you to specify the HAZ Outer Diameter 2. By default, this checkbox is cleared and the HAZ Outer Diameter 2 cannot be defined.
HAZ Outer Diameter 2	values Specify an absolute value for the width of the second layer around the HAZ Outer Diameter. scale factors Specify a width for the second layer around the HAZ Outer Diameter. Calculated as a scale factor from the nugget diameter. offsets Specify a width of the second layer around the HAZ Outer Diameter, which is offset from the HAZ Outer Diameter. Note: For values and scale factors, this value must be greater than the value used for defining the HAZ Outer Diameter.

Property and Material Info

Use the Property and Material Info parameters to define the properties and materials of the welds and the heat affected zones (HAZ).

Table 8.
Parameter	Option
HAZ Material Option	Choose a method for assigning material for the HAZ. Use original material Assign a new HAZ component with the same material that was assigned to the original components. Use copy of original material Duplicate the original materials and assign them to new components. The original material is duplicated. The new material name will be the same as the original material with _HAZ_mat as a postfix. Select a material Select a material from the current model via the select material for HAZ option. HAZ components are created with the same name as the selected material with property ID as a postfix. When set to <unspecified>, a default material is taken from the [hm_scripts_dir]/connectors/hexa_nugget/dyna/hexa_nugget_HAZ_material_default.ini file. HAZ components are created with name hexa_nugget_HAZ_mat_default_ and with the property ID as a postfix.
HAZ Property Option	Choose a method for assigning a property to HAZ. Use original property Assign a new HAZ component with the same property that was assigned to the original components. Use copy of original material Duplicate the original properties and assign them to new components. The original property is duplicated. The new property name will be the same as the original property with _HAZ_prop as a postfix. Scale original thickness Create a new property and component for each link that has a HAZ imprinted. The property is a copy of the original. Properties are named as <originalname>_<HAZ_prop>_<scaled thickness>, and components are named as <matname>_<scaled property name>. Input thickness Create a new property and component for each link that has a HAZ imprinted. The property is a copy of the original. Property is named as <hexa_nugget_HAZ_prop>_<thickness_value>, and components are named as <matname>_<Input thichness prop name>. Select a property Select a property from the current model via the select property for HAZ option. HAZ components are created and named using the UHSS material with the property ID as a postfix. For example, <UHSS matname>_<prop ID>.
Nugget Material Option	Choose a method for creating and assigning material to nuggets. Create one material per each link combination Create one material for each link combination. The weld material is named <hexa_nugget_weld_mat>_<link 1 ID/name>_<Link 2 ID/name>. If the link with ID 1 and the link with ID 2 are connected, than the weld material which gets created will be named hexa_nugget_weld_mat_1_2. Create one material per each number of layer Create one material based on the number of layers the weld is connecting to. The weld material is named <hexa_nugget_weld_mat>_<link 1 ID/ name>_<No. of layers>. If it is a 2T weld, than the mat name will be hexa_nugget_weld_mat_2L. If it is a 3T weld, than it will be named hexa_nugget_weld_mat_3L. Use one single weld material Select a weld material from the current model using Select Nugget Material Option. The selected material will be assigned to all weld elements.
Itemize Multilayer Connections	Itemize a multilayer connection. For example, in the case of a three layer connection, the two hexa clusters will be handled separately and will be assigned two different materials. At the same time, a two layer connection between the same two links will be assigned another material. Names are created as following: hexa_nugget_weld_material_link1_link2_(link3) Ideally the links are ordered as <outer involved link>_<inner involved link>_(<uninvolved comp>), so that the two links involved come first, and the link(s) that are not involved are written in brackets. hexa_nugget_weld_material_link3_link2_(link1) Ideally the links are ordered as <outer involved link>_<inner involved link>_(<uninvolved comp>), so that the two links involved come first, and the link(s) not involved are written in brackets. hexa_nugget_weld_material_link1_link2, hexa_nugget_weld_material_link2_link3 All materials are derivatives from [hm_scripts_dir]/connectors/hexa_nugget/radioss/hexa_nugget_weld_material_default.ini Note: Only available when Nugget Material Option is set to Create one material per each link combination.
Select Nugget Property	Select a property from the current model.

Behavior

Table 9.
Parameter	Option
Non-normal	Attempt to realize connectors if the shell layers are not normal to each other.
Project Hexa Faces To Shell	Investigate and project each individual node, enabling you to expect and accept penetrations. In some border cases, during realization not all nodes of the appropriate hexa(cluster)-side are positioned exactly on the shell. This is due to some simplifications during the projection routine because it is estimated that the shells will not be too curvy and will be pretty plain. Therefore, not every node is individually investigated and projected to the same plane as the first one.
Ensure Hexa Projection	When enabled, all hexa node projections to a link that are beyond the specified tolerance (0.01*diameter) are marked as an error. Tip: Enable this checkbox when working with connections that use a contact definition.
Preserve Washer	Choose a method for preserving washers during the realization. Initial situation with perfectly meshed washers. Figure 2. Original After realization, with no washer preservation. The washers have been opened. Figure 3. No Washer Preservation After realization, with washer preservation and remesh allowed. The washers are still intact, but the mesh seeding has been changed. Figure 4. Preserve Washer, Allow Remesh After realization, with washer preservation and no remesh allowed. The washers have been fully preserved. Figure 5. Preserve Washer, No Remesh
Feature Angle	Specify a value used to determine important features, which need to be kept when doing the imprint. Note: Features crossing the HAZ and close by cannot be kept.
Nugget Narrow Case	Choose a method to control the edge treatment, and HAZ element snapping to edge, if the connector is close to the edge. Do Nothing This option does not allow the HAZ nodes or edge nodes to be snapped. Figure 6. Do Nothing Allow HAZ Nodes to Snap to Edge This option allows HAZ nodes of hexa nugget connectors to snap to free and feature edges. Figure 7. Allow HAZ Nodes to Snap to Edge Allow Edge to Move Away from Nugget This option allows edge nodes of components to move away from HAZ nodes to avoid the creation of elements that fail for minimum size. Figure 8. Allow Edge to Move Away from Nugget Allow Edge to Snap to HAZ Layer This option allows edge nodes of components to snap to HAZ nodes to avoid creation of elements that fail for minimum size. Figure 9. Allow Edge to Snap to HAZ Layer Skip HAZ This option skips the creation of HAZ elements during connector realization. Figure 10. Skip HAZ
Nugget Orientation	Choose a method for orienting hexa nuggets during the realization. Auto The orientation of hexa elements is auto-decided based on the best element quality that can be achieved. Figure 11. Auto Parallel to Edge Hexa elements are oriented so that a hexa element edge is always parallel to a free edge of a connecting link. Figure 12. Parallel to Edge Point to Edge Hexa elements are oriented so that a node of hexa element is always pointed to a free edge of connecting links. Figure 13. Point to Edge
Post Collector Name Setting	While realizing a hexa nugget connector, choose to name the collectors created after the realization with link names or link IDs.
Post Collector Name Separator	Choose a separator to use between collector names.
Unrealize Remesh or Rebuild	Remeshes or rebuilds HAZ elements and the elements surrounding it upon connector unrealization. Option is available only when unrealize remesh or rebuild is set to Remesh or Rebuild. Number of layers to be considered around HAZ elements for remesh or rebuild can be controlled with user input value for the layers. None No remesh or rebuild of HAZ's and surrounding elements on unrealizing connectors. Remesh The mesh around the connector is remeshed by a specified number of layers on unrealizing connector. Rebuild The mesh around the connector is rebuilt by a specified number of layers on unrealizing connector.