Seam Quad

This realization realizes t-welds, lap-welds, laser-welds, and butt-welds.

Restriction: Available in Abaqus, LS-DYNA, Nastran, OptiStruct, and Radioss.

This weld type is identified automatically based on the orientation of the links to each other.

The dimensions and properties assigned to all heat affected zones (HAZ) can be defined separately. Normal directions of quad weld elements and HAZ elements can be controlled. An edge treatment can be defined for t-welds and butt-welds to move the edge a precise distance from the opposite link.

General Info

Weld Type

Defines weather to setup a configuration exclusively for a T, L, or B connection, or automatically setup a configuration for each connection based on the angle.

The connection type is dependent on the:

B/L classification angle
L/T classification angle

Tolerance

Defines the distance from the connector location.

Only 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

T Weld Shape

Defines how the T weld is created.

Figure 5. Vertical (edge) and angled (double)

Figure 7. Vertical (edge) and angled (horizontal)

Use Extension

Interpolate an extension of the T joint and calculate the weld dimensions from this location.

Extension Angle

If the Links are at an angle greater than the “Extension Angle” then the “Use Extension” operation is used.

L Weld Shape

Defines how the L weld is created.

B Weld Shape

B welds are always created straight.

With Caps

When enabled, seams are closed with a tria element.

The Caps option in Realization Details determines how the caps are created.

Coat

The number of elements in the weld.

Allow Tria Weld

This option allows the realization to use Trias in the weld and HAZ. This can improve element quality on connectors with a very tight radius.

Realization Details

The Realization Details settings position the yellow marked nodes in the following figures. The dimensions of the welds are dependent on the Weld Shape settings.

Figure 16. T Dimensions	Figure 17. L Dimensions
Figure 18. B Dimensions

Dimensioning Scheme

Defines the dimensioning scheme for the dimensions of the T weld, L weld, and B weld connections.

user input: Manually define discrete values for the weld dimensions, shown in black in Figure 16, Figure 17, and Figure 18. The horizontal dimensions can be defined using a length or an angle.
thickness dependent: Choose a formula to define the weld dimensions, shown in black in Figure 16, Figure 17, and Figure 18. The provided formulas are all dependent on the thicknesses t1 and t2. A formula can be chosen individually for each verticalV and horizontalH distance, or the same formula can be used for T, L and B.
weldsize dependent: Manually define discrete values for the weld dimensions, shown in red in the Figure 16, Figure 17, and Figure 18. The verticalV and horizontalH distances are defined with formulas reflecting the weld sizes and the t1 and t2 thicknesses.

DIM T (Dimensioning T)


	Input	Thickness dependent	Weldsize dependent
Horizontal Lengths LTH	by angle by length	Pitch Size T1 T2 (T1+T2) (T1+T2)/2 T Minimum T Maximum Lh, LB, LV Factor*	t1/2+wh/2
Vertical Length LTV	by length by edge	By Edge Pitch Size T1 T2 (T1+T2) (T1+T2)/2 T Minimum T Maximum By edge + 0.4T1 Lh, LB, LV Factor	t2/2+wv/2 by edge

DIM L (Dimensioning L)


	Input	Thickness dependent	Weldsize dependent
Horizontal Lengths LTH	by length by angle	Pitch Size T1 T2 (T1+T2) (T1+T2)/2 T Minimum T Maximum Lh, LB, LV Factor*	wh/2

DIM B (Dimensioning B)


	Input	Thickness dependent	Weldsize dependent
Lengths LB	by length by angle	Pitch Size T1 T2 (T1+T2) (T1+T2)/2 T Minimum T Maximum Lh, LB, LV Factor*	wb by edges

*LH, LB, LV Factor: Is a calculation factor that can be added to the calculation. The default value is 1.0, so the length calculation selection remains unchanged.

Use Edge to T, B

If the weld is classified as a T or a B weld, the weld is created from the edge. You do not need to put any values in for Vertical Length for T welds and Width for B welds.

Edge Treatment

Treatment: Try to move the edges of the mesh to meet the dimension scheme. Edge treatment is not needed when the different length dimension settings are set to by edge. When enabled, edges are allowed to move.
Keep: Keep the mesh if the weld is realizing above the edge.
Cut: Trim the mesh below the weld if the weld is realizing above the edge.

Max Length Value

Defines the maximum length value.

This setting is useful when lengths are calculated based on thicknesses. If a length is greater than the Max Length Value, then the Max Length Value will be used instead.

Caps

Determines how caps are created.

Element Details

The Element Details settings control the normal directions of the weld, as well as the HAZ elements.

Vertical Element Normal, Angled Element Normal, and HAZ Element Normal can be set to either:

Towards welder: The element normals are in the direction of the weld.
Away from welder: The element normals are in the opposite direction of the weld.

Connectivity Info

The following options give you the ability to change how the realization connects to the mesh.

imprint (default): Creates quad weld elements and stitches them to both links by adjusting their mesh. The HAZ is created in this option.
skip imprint: Creates quad weld elements but does not change the meshes of the links. Instead, additional elements are created to represent the requested HAZ. These elements are organized in the ^conn_imprint component and can later be used for a manual imprint after they have been manipulated to your needs. This option is helpful when working with more complex areas, where the standard imprint functionality fails, for example, conflicting connectors.
imprint/no HAZ: Creates quad weld elements and stitches them to both links by adjusting their mesh. Mesh modifications are as minimal as possible and no HAZ are performed.
none: Creates quad weld elements only. Quad weld elements will not be attached to the links. The connection will need further attention.

HAZ Info

The HAZ Info settings define the lengths of the different heat affected zones (HAZ), which are dependent on the HAZ lengths for T, L and B (defined in Realization Details). The HAZ length settings vary depending on the defined weld shapes (vertical, angled, vertical and angled, caps).

Rule-based realization:

First try to realize with user-specified HAZ lengths.
If step 1 fails, realize with reduced HAZ lengths/reduced HAZ’s elements length at certain position on connectors.
If step 2 also fails, realize with no HAZ’s.

HAZ Scheme

Choose a dimensioning scheme for the HAZ lengths of T, L, and B.

input: Enables you to decide if the HAZ lengths should be defined individually, or if all HAZ lengths are determined using the same approach (same as all).
weldsize dependent: Only available if weldsize dependent has been chosen for the Dimensioning Scheme as well.

HAZ Lengths

same as all: Assigns the same length to all HAZ lengths.
individual: Assign HAZ lengths individually.

HAZ Lengths (various)

The following options are available in the various HAZ length settings.

input: Requires a discrete value be specified for the length.
average meshsize: Length is dependent on the average mesh size in the local area where the imprint is performed.
by thickness: Sets the length to the same value as the thickness of the link getting the HAZ.
LTH: Horizontal length for T connections, which is the length between the foot points of the vertical and angled part of a seam.
LLH: Horizontal length for L connections, which is the length between the foot points of the vertical and angled part of a seam.
LB: Butt weld length.
skip HAZ: Skips individual HAZ that are not required.
same as positive side: Assigns the same length as the positive side to the negative side.
wh or wh/2: Length is dependent on the horizontal weld size. Only available when HAZ Scheme is set to weldsize dependent.
wv or wv/2: Length is dependent on the vertical weld size. Only available when HAZ Scheme is set to weldsize dependent.
wb or wb/2: Length is dependent on the butt weld size. Only available when HAZ Scheme is set to weldsize dependent.
LTVedge: Choose between skip HAZ and LTVedge. Only available for the HAZ_Tvedge length.

HAZ Length Factor (Avg. Meshsize/Thickness)

Factor that increases or decreases the HAZ lengths, which have been defined using the average meshsize or by thickness length options.

Max HAZ Length

Maximum length for all HAZ lengths. If the HAZ length is greater than this value, then the Max HAZ Length is used.

Dimensioning and Heat Affected Zones (HAZ):

Dimensioning T

Figure 27. Vertical and Angled T Weld HAZ

Dimensioning L

Figure 31. Vertical and Angled L Weld HAZ

Dimensioning B

Property and Material Info

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

HAZ Organize Scheme

Choose a HAZ organize scheme:

inherit property: Inherits the elements of the HAZ from the links in which the HAZ elements are imprinted.
general property: Assigns the same HAZ property throughout one link, or throughout all links.; Use the subsequent options to define how the properties are determined.
individual property: Assigns individual properties to each HAZ.

HAZ Component Option

stay in original: Keeps HAZ elements in the component they were imprinted into. No additional properties get created.
new component per original one: Creates a new component for each component that gets a HAZ imprinted. The direct property assignment setting is ignored when this option is selected.

HAZ Property Option

The options available are dependent on the HAZ Organize Scheme selected.

assign original property

Assigns the same property that was assigned to the original components to new components.

assign duplicated property

Duplicates the original properties and assigns them to new components.

select

Select a property from the current model via the Select Property For HAZ option. Unless direct property assignment is activated, a component named ltb_seam_quad_haz_ with the property ID as a postfix is created.

same as original

Assigns HAZ elements the same property as the original. No further properties are created. HAZ elements are organized into components named ltb_seam_quad_haz_ with the property ID as postfix.

scaled original thickness

Creates 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 ltb_seam_quad_haz_<linkname>_<scaled thickness>, and components are named the same as the properties.

In addition, you can define the following:

HAZ thickness factor

Enables entering a factor to scale the thickness.

HAZ Property Grouping

Groups properties in order to reduce the amount of properties created.

Do not group: Prevents grouping.
group same thickness: Groups HAZ elements with the same thickness into one property and component. HAZ elements of T, L, and B welds are also grouped together if they have the same thickness.; Properties are named ltb_seam_quad_haz_<scaled thickness> or ltb_seam_quad_haz_<property ID>, and components use the same name as properties.
group same thickness within T, L, and B: Groups all HAZ elements with the same thickness into one property and component, as long as they have the same weld type of T, L, B.; Properties are named ltb_seam_quad_<t or l or b>_<thickness>, and components use the same name as properties.

input thickness

Creates a new property and component for each link that has a HAZ imprinted.

The property is a copy of the original. Properties are named ltb_seam_quad_haz_<linkname>_<scaled thickness>, and components are named the same as the properties.

In addition, you can define the following:

HAZ thickness

Enables a factor for thickness to be entered.

HAZ Property Grouping

Groups properties in order to reduce the amount of properties created.

do not group: Prevents grouping.
group same thickness: Groups all HAZ elements with the same thickness into one property and component. HAZ elements of T, L, and B welds are also grouped together if they have the same thickness.; Properties are named as ltb_seam_quad_haz_<scaled thickness> or ltb_seam_quad_haz_<property ID>, and components use the same name as properties.
group same thickness: Within T, L, and B groups all HAZ elements with the same thickness into one property and component as long as they have the same weld type of T, L, B.; Properties are named as ltb_seam_quad_<t or l or b>_<thickness>, and components use the same name as properties.

same as positive side

Guarantees the HAZ on the positive and negative side of the T or L weld are assigned the same property.

same as the other size

Guarantees the HAZ on both sides of the B weld are assigned the same property.

Weld Property

Define how the thicknesses for the different parts of the weld are determined. Appropriate PSHELL properties are created.

Property Option For Vertical Quads


Property Calculation Method	PID T Maximum T Minimum T1 T2 (T1 + T2)/2 (T1 + T2) LH/sqrt(2) (LH/sqrt(2) + LV/sqrt(2))/4 Same as Edge *Property Factor

Property Option for Horizontal Quads


Property Calculation Method	PID T Maximum T Minimum T1 T2 (T1 + T2)/2 (T1 + T2) LH/sqrt(2) (LH/sqrt(2) + LV/sqrt(2))/4 Thickness *Property Factor

*Property Factor: Is a calculation factor that can be added to the calculation. The default value is 1.0, so the thickness calculation selection remains unchanged.

PID: Select a property from the current model via the Select Property For Vertical Quad field. Unless direct property assignment is activated, a component with the the name ltb_seam_quad_weld_ and the property ID as postfix is created.
Lh/sqrt(2): Determines the thicknesses of welds. Options are dependent on the weld type (T, L, B) and the selected weld shapes (vertical, angled, vertical and angled).
(Lh/sqrt(2)+Lv/sqrt(2))/4: Properties are named ltb_seam_quad_weld_<weldshape>_<link1>_<link2>_<thickness>, and components are named the same as the properties and host the weld elements. Lh is the superset of LLH and LTH (see dimensions above). Lv is the superset of LLV and LTV (see dimensions above).
same as edge: Inherits the property of the link with the free edge for the vertical weld. Unless direct property assignment is activated, a component with the name ltb_seam_quad_weld_ with the property ID as postfix is created.
input thickness: Creates properties with the required thicknesses for each link combination and weld shape (vertical, angled, straight). The properties are named ltb_seam_quad_weld_<weldshape>_<link1>_<link2>_<thickness>, and the corresponding components are named the same as the properties and host the weld elements.

Weld Property Grouping

Reduce the number of properties created by grouping them, except when using the select and same as edge options.

do not group: No grouping will take place. Properties are created as described in previous options.
group same thickness: Groups all weld elements with the same thickness into one property and one associated component. Vertical, angled, and straight weld elements that have the same thickness are also grouped together.; Properties are named ltb_seam_quad_weld_<thickness>, and their associated components are named the same as the property.
group same thickness within vertical, angled + capped and straight quads: Groups all weld elements with the same thickness and weld shape (vertical, angled + capped, straight) into one property and one associated component.; Properties are named ltb_seam_quad_<vertical or angled_capped or straight>_<thickness>, and their associated components are named the same as the property.

By Weld If Possible

Create components per Connector.

Direct Property Assignment

Stops additional components from being created, and directly assigns created or selected properties to individual weld or HAZ elements.

Behavior

B/L classification angle

Angle that is automatically determined for each individual seam connector, whether it is to be considered a butt weld or a lap weld. Default is set to 10.0°.

If the angle of the two links is smaller than the B/L classification angle, then it will be considered a butt weld and a lap weld; a further check determines whether the links overlap. If the links do not overlap, a butt-weld is performed.

L/T classification angle

Angle that is automatically determined for each individual seam connector, whether it is to be considered a lap weld or a t-weld. Default is set to 10.0°.

Angle Direction

Defines which side the angled weld elements are created.

connector side: Angled weld elements are created on the side where the connector is located, as long as the connector is not perfectly on the free edge.; If the connector is on the free edge, the edge quad normal option will be automatically used.
positive side/negative side: The positive and negative side can be determined as long as the links are not perfectly perpendicular to each other.
Figure 34. . Overview of how the positive and negative side is determined. When links are perfectly perpendicular, the edge quad normal option is automatically used.
edge quad normal: Figure 35. . Overview of how the side for the angled weld is determined. If the normal directions are reversed, the side of the angled weld changes.

Snapping to Edge

Automatic edge snapping can be used to precisely position connectors. First, the connector snaps to, for example, the closest free edge, then the projection and FE creation starts.

The snapping distance can be defined separately for T, L and B connections.

You can choose whether to snap to:

maximum 1 element row
maximum 2 element rows
no (connector does not snap)

Figure 36. Original Model before Realization. Initial situation with one element row marked for the lap weld and two element rows for the t weld.	Figure 37. Edge Snapping Enabled
Figure 38. Edge Snapping Disabled

Edge Treatment (T/B)

Attempts to create specific vertical lengths for T connections LTV, and specific lengths for B connections LB.

Only enabled when the Edge Treatment setting is enabled from the Realization Details settings.

Figure 39. Original Model before Realization

Figure 40. Realization using Edge Treatment. Free edges were contracted or extended.

Edge Treatment Options

Choose whether to:

extension and contraction
extension
contraction

Edge Treatment Limit

Edge treatment is a pure node movement; therefore, the maximum movement needs to be limited to prevent the elements at the edge from being destroyed. Movement is limited to a maximum of 0.5 times the element size at the edge. 0.5 is the maximum allowed value and default value.

Preserve Washer

Controls how washers are preserved during the seam imprint realization.

Figure 41. Original Mode with Perfectly Meshed Washers	Figure 42. No Washer Preservation Enabled. Washers have been opened.
Figure 43. Washer Preservation and Remesh Enabled. Washers are still intact, but the mesh seeding has been modified.	Figure 44. Washer Preservation and No Remesh Enabled. The washers have been fully preserved.

Do Not Share Zone Elements

Seam imprint allows heat affected zones (HAZ) to be merged in close areas. In this situation, one element might touch the weld elements from two different connectors. Do not share zone elements prevents zone elements from being shared.

Quad In Corner

Controls whether a single or double element is created in corners of quad seam connectors with a certain vertex.

A angle must be defined for a single quad corner. If the corner angle is greater than the defined angle, a double quad corner is created.

Figure 45. Quad in Corner. A double quad corner is shown on the left, and a single quad corner is shown on the right.

Quad Control

Controls the maximum deviation from the perfect quad element for the heat affected zone (HAZ). It can be controlled, if the element size or the element skew is more important to retain.

Max Quadsize Reduction In % / Max Quad Skew In Degrees

Figure 46. Max Quad Size Reduction: 80.0 / Max Quad Skew: 5.0

Figure 47. Max Quad Size Reduction: 5.0 / Max Quad Skew: 45.0

Silver Elements

Sliver elements are small elements that you may not want in your model. In the images below, a perfect perpendicular projection resulted in sliver elements. The Sliver Elements setting can be used to manage sliver elements in your model. In the images below, the red elements represent the HAZ elements.

Figure 48. Allow	Figure 49. Prevent by Moving Projection Points
Figure 50. Prevent by Moving Edge	Figure 51. Delete Sliver Elements

Element length<

This length controls which elements to treat as sliver elements.

Feature Angle

Determines important features to retain during the imprint. Features that cross the HAZ, as well as near by features cannot be retained.

Seam Test Point Alignment: A global option. If the seam connectors are close by activating “Seam test Points Alignment” option in connector entity editor, the test point alignment is based on the proximity of other connectors to get better mesh flow. It also ensures the cross-over connector should have a common test point, so that unique nodes will be created.
Seam Loose Ends: A local option set on individual connectors. Enabling “Seam Test Points Alignment” will also enable this option, which allows for the alignment of start and end points of seam connectors along with alignment of other test points.
Seam Fixed: A local option set on individual connectors. Enabling the “Seam Fixed” option considers all the test points of seam connectors as fixed and will not be disturbed.
Seam Consider Feature and Boundaries: A local option set on individual connectors. Enabling the "Seam Consider Feature and Boundaries" option will adjust test points so the projections fall on features/boundaries wherever possible. Overhanging test points will be trimmed.
Figure 52. Without Seam Consider Feature and Boundary

Figure 53. With Seam Consider Feature and Boundary
Partial Imprint Percentage: The allowable percentage of the connector to realize and still be classified as "Realized".