Seam-Rigid LTB

The dimensions and property for all heat affected zones (HAZ) can be defined separately. 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-Rigid 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.

The image below shows where the master and slave nodes of the rigid elements will be placed.

Figure 5. Vertical T Weld	Figure 6. Angled T Weld, Connected to Edge
Figure 7. Vertical and Horizontal T Weld	Figure 8. Angled T Weld, Connected at a Defined Vertical Height LTV

L Weld Shape

Defines how the L weld is created.

The image below shows where the master and slave nodes of the rigid elements will be placed.

Figure 9. Vertical L Weld	Figure 10. Angled L Weld
Figure 11. Vertical and Angled L Weld

B Weld Shape

B welds are always created in a straight manner.

The image below shows where the master and slave nodes of the rigid elements will be placed. The nodes can also be placed the opposite direction, but their position will always be consistent throughout each seam.

Figure 12. Straight B Weld

The Realization Details settings position the yellow marked nodes in Figure 13, Figure 14, and Figure 15.

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 13, Figure 14, and Figure 15, 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 13, Figure 14, and Figure 15, 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 Figure 13, Figure 14, and Figure 15. 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.

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 your 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 the Realization Details parameters. 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.

Assign HAZ lengths individually

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 16. Dimensioning T

Figure 17. Vertical T Weld HAZ	Figure 18. Angled T Weld HAZ	Figure 19. Vertical and Angled T Weld HAZ

Dimensioning L

Figure 20. Dimensioning L

Figure 21. Vertical L Weld HAZ	Figure 22. Angled L Weld HAZ	Figure 23. Vertical and Angled L Weld HAZ

Dimensioning B

Figure 24. Dimensioning B

Figure 25. Straight B Weld HAZ

The Property and Material Info settings 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_rigid_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_rigid_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_rigid_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 you to enter 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_rigid_quad_haz_<scaled thickness> or ltb_rigid_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_rigid_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_rigid_quad_haz_<linkname>_<scaled thickness>, and components are named the same as the properties.

In addition, you can define the following:

HAZ thickness

Enables you to enter a factor for thickness.

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_rigid_quad_haz_<scaled thickness> or ltb_rigid_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_rigid_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.

Direct Property Assignment

When activated, additional components will not be created, and created or selected properties will be directly assigned to individual weld or HAZ elements.

Used for HAZ and weld property assignment.

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 26. . 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 27. . 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 28. Original Model before Realization. Initial situation with one element row marked for the lap weld and two element rows for the t weld.	Figure 29. Edge Snapping Enabled
Figure 30. Edge Snapping Disabled

Edge Treatment (T/B)

The Edge Treatment(T/B) setting attempts to create specific vertical lengths for T connections LTV, and specific lengths for B connections LB.

Figure 31. Original Model before Realization	Figure 32. 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 33. Original Mode with Perfectly Meshed Washers	Figure 34. No Washer Preservation Enabled. Washers have been opened.
Figure 35. Washer Preservation and Remesh Enabled. Washers are still intact, but the mesh seeding has been modified.	Figure 36. 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. Don't 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 37. 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 38. Max Quad Size Reduction: 80.0 / Max Quad Skew: 5.0	Figure 39. Max Quad Size Reduction: 5.0 / Max Quad Skew: 45.0

Sliver 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 40. Allow	Figure 41. Prevent by Moving Projection Points
Figure 42. Prevent by Moving Edge	Figure 43. 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.