Seam-Quad LTB

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.

Figure 1. Seam-Quad LTB

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.

In any case, the connection type is dependent on the:

• B/L classification angle
• L/T classification angle

Both types of angles are defined in the Behavior section.

Figure 2. T Connection	Figure 3. L Connection
Figure 4. B Connection

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.

T Weld Shape

Defines how the T weld is created.

Figure 5. Vertical T weld	Figure 6. Angled T weld
Figure 7. Vertical and angled T weld

L Weld Shape

Defines how the L weld is created.

Figure 8. Vertical L weld	Figure 9. Angled L weld
Figure 10. Vertical and angled L weld

B Weld Shape

B welds are always created in a straight manner.

Figure 11. Straight B weld

With Caps

When enabled, seams are closed with a tria element.

The Caps settings determines how the caps are created.

Figure 12. Tria cap element for T weld	Figure 13. Tria cap element for L weld

The Realization Details settings position the yellow marked nodes in the Figure 14, Figure 15, and Figure 16.

The dimension of the welds are dependent on the Weld Shape settings.

Dimensioning Scheme

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

input

Manually define discrete values for the weld dimensions, shown in black in Figure 14, Figure 15, and Figure 16, with the exception of thickness. 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 14, Figure 15, and Figure 16, with the exception of thickness. 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 14, Figure 15, and Figure 16. 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	(t1+t2)/2 3*(t1+t2)/2 t1+t2	t1/2+wh/2 (fix)
Vertical Length LTV	by length by edge	(t1+t2)/2 3*(t1+t2)/2 t1+t2 by edge	t2/2+wv/2 by edge

DIM L (Dimensioning L)

	Input	Thickness dependent	Weldsize dependent
Horizontal Lengths LTH	by length by angle	(t1+t2)/2 3*(t1+t2)/2 t1+t2	wh/2 (fix)

DIM B (Dimensioning B)

	Input	Thickness dependent	Weldsize dependent
Lengths LB	by length by angle	(t1+t2)/2 3*(t1+t2)/2 t1+t2 by edge	wb by edges

Edge Treatment (T/B)

When discrete lengths are requested for T and B connections, it is sometimes necessary to move the edges.

Edge treatment is not needed when the different length dimension settings are set to by edge.

When enabled, edges are allowed to move. See Edge Treatment Options for more information.

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.

Figure 17. Cap Angle and Runoff Angle

Figure 18. Sharp Corner Enabled	Figure 19. Sharp Corner Disabled

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

Towards welder

Shows the normal directions

Away from welder

Shows the exact opposite.

imprint (default)

Creates quad weld elements, and stitches them to both links by adjusting their mesh. All required HAZ are performed.

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 the users needs. This option can be 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.

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).

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 22. Dimensioning T

Figure 23. Vertical T Weld HAZ	Figure 24. Angled T Weld HAZ	Figure 25. Vertical and Angled T Weld HAZ

Dimensioning L

Figure 26. Dimensioning L

Figure 27. Vertical L Weld HAZ	Figure 28. Angled L Weld HAZ	Figure 29. Vertical and Angled L Weld HAZ

Dimensioning B

Figure 30. Dimensioning B

Figure 31. Straight B Weld HAZ

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

select

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.

0.5*Lh/sqrt(2)

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.

Property Option for Angled Quads

select

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.

0.5*Lh/sqrt(2)

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.

(t1+t2)/2

Lh is the superset of LLH and LTH (see dimensions above). Lv is the superset of LLV and LTV (see dimensions above).

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.

Property Option for Capped Quads

select

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.

0.5*Lh/sqrt(2)

Options are dependent on the weld type (T, L, B) and the selected weld shapes (vertical, angled, vertical and angled).

(t1+t2)/2

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).

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.

Property Option for Straight Quads

(t1+t2)/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).

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).

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.

Direct Property Assignment

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

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 32. . 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 33. . 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 34. Original Model before Realization. Initial situation with one element row marked for the lap weld and two element rows for the t weld.	Figure 35. Edge Snapping Enabled
Figure 36. 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 37. Original Model before Realization	Figure 38. 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 39. Original Mode with Perfectly Meshed Washers	Figure 40. No Washer Preservation Enabled. Washers have been opened.
Figure 41. Washer Preservation and Remesh Enabled. Washers are still intact, but the mesh seeding has been modified.	Figure 42. Washer Preservation and No Remesh Enabled. The washers have been fully preserved.

Don't 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 43. Quad in Corner. A double quad corner is shown on the right, and a single quad corner is shown on the left.

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 44. Max Quad Size Reduction: 80.0 / Max Quad Skew: 5.0	Figure 45. 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 46. Allow	Figure 47. Prevent by Moving Projection Points
Figure 48. Prevent by Moving Edge	Figure 49. 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.