Several properties and user-defined attributes enable you to control how Tekla Structures creates analysis models.
To modify the user-defined attributes, open the part properties dialog box and click the User-defined attributes... button to open the attributes dialog box.
You can also modify several properties on the Analysis and Analysis (2) tabs of the attributes dialog box:
Use the analysis model geometry settings and analysis properties of parts to define how Tekla Structures creates analysis models. See Analysis model geometry (p. 57) and Analysis part properties (p. 61).
Attribute Description Options/Values Node offsets Moves the part in the analysis
model when members do not meet and are not connected.
Consider longitu-dinal model offsets
Controls the member longitu-dinal offsets.
Auto (default) uses the Dx end offset if it extends the beam, or if it shortens the beam and there is a node near the shortened posi-tion.
None
Extending only uses the Dx end offset when it extends the beam, and ignores it when it shortens the beam.
Always No. of split nodes Use to create additional nodes or
analyze a beam as straight segments, for example, a curved beam.
See also Adding intermediate nodes (p. 33).
Enter the number of nodes.
Split distances To define additional nodes in the member, enter distances from the part starting point to the node.
See also Adding intermediate nodes (p. 33).
Enter distances, separated by spaces, for example:
1000 1500 3000
Curved beam by straight segments
Use to analyze a curved beam as straight segments.
Yes No Node merge
distance
Merges nodes within the distance specified into a single node.
For example, use this to force truss-type analysis members to meet in the analysis model.
The Keep axis attribute over-rides this attribute.
Distance
Design group (opti-mization)
Defines which design group the part belongs to. Used in optimi-zation.
Member level (z) Sets the same z coordinate for all nodes.
Enter a value for the z coordi-nate.
Profile Analysis part profile.
You can use different analysis profiles at the start and end of parts if the analysis application you use supports it.
Select a profile from the profile catalog.
To use different profiles at part ends, enter two profiles separated by a pipe character, for example:
HEA120|HEA140
Connect to (part IDs)
Forces or disables connections between the analysis members you specify.
Works with the Connect exclu-sively attribute.
To enable connections, enter the part ID’s, separated by spaces.
To prevent connection, enter negative part ID’s, separated by spaces.
Connect exclusively Select Yes to connect the part only to the parts defined by the Connect to (part IDs) attribute.
Keep axis Select Yes to fix the location of member axis so that Tekla Struc-tures does not shift the axis when it makes members meet in the analysis model.
For example, use this with the Node merge distance attribute to force truss-type members to meet in the analysis model.
Overrides the Node merge distance attribute.
Rigid link Enables or disables rigid links at the start, mid, and end points of parts.
Use with the Force to centric connection option in the Anal-ysis Model Properties dialog box to specify which parts to use rigid links.
See also Using rigid links (p.
34).
•
100 = rigid link at start point•
111 = rigid links at start, mid, and end point•
001 = rigid link at end point Pinned rigid link (topart names)
Connects the part using pinned rigid links to the parts you specify.
Enter the part names, separated by spaces, commas, or semico-lons. You can also use wildcards (see Using wildcards in the Modeling Manual).
Thickness Analysis plate thickness.
Minimum hole size (to consider)
Use to ignore small openings in plates in the analysis.
Enter the size of the bounding box around the opening.
Short cantilever limit (to remove)
Use to ignore short plate cantile-vers in the analysis.
Enter a cantilever length.
Mesh point IDs (add/
remove)
Use to exclude nodes from or include nodes in plate element meshes.
Only nodes created because of connected members or loads can be excluded.
To include nodes, enter the point ID’s, separated by spaces.
To exclude nodes, enter negative point ID’s.
For example:
1203 -1205 -1206
Attribute Description Options/Values
See also To find out how to create user-defined attributes, see Adding properties in the System Manual.
Adding intermediate nodes
Sometimes intermediate nodes are needed along a member, for example in frequency analysis.
To create additional nodes, use the following user-defined attributes on the Analysis tab of the part properties dialog box:
•
No. of split nodesEnter the number of nodes. Tekla Structures gives equal spacing to added nodes.
•
Split distancesEnter the distance values from the part starting point. Tekla Structures adds nodes using these distances:
Simple plate Select Yes to create a simpler analysis model of plates, where cuts and openings are not consid-ered.
Trim plate connec-tions
Select No to connect plates using rigid links, without moving nodes.
Select Yes to connect plates by moving plate nodes, instead of using rigid links.
Supported Use to define supports for plates and beams.
You can create supports for the bottom edge of a wall, for all edge nodes of a slab, or for all nodes of a beam. For walls the bottom edge can be inclined.
Simply: only translations are fixed
Fully: both translations and rota-tions are fixed
Some attributes are only available if you select the Extended clash check checkbox in the Analysis Model Properties dialog box. They are:
•
Rigid link•
Node merge distance•
Connect to (part IDs)•
Connect exclusively•
Keep axisFor more information on the Extended clash check, see Creating common nodes (p. 37).
Attribute Description Options/Values
Using rigid links
You can enable or disable rigid links using the Node definition method (p. 67) in the entire analysis model. You can override this setting in specific places:
•
If Node definition is Force to centric connection, rigid links are generally not used, but it is possible to force rigid links in specific places.•
If Node definition is Use rigid links, rigid links are used, but it is possible to prevent the use of rigid links in specific places.To define rigid links, use the user-defined attribute Rigid link in the part properties.
The value of the attribute is a three-digit number of 1’s and/or 0’s.
•
1 = rigid link enabled•
0 = rigid link disabledThe first digit is the setting for the part start point, the second digit is the setting for all intermediate points between the start and end point, and the third digit is setting for the part end point.
A rigid link is created at a connection between two members if:
•
An eccentric connection exists.•
Rigid links are enabled for both parts, either as an analysis model property or user-defined attribute of parts.Example 1 The node definition method of the analysis model is Force to centric connection. If the Rigid link attribute is not set, there will be no rigid link. To create the rigid link, use the following values of the user-defined attribute Rigid link:
Example 2 The node definition method of the analysis model is Use rigid links. If the Rigid link attribute is not set, there will be rigid links. To disable rigid link between two members, set the attribute for one part only:
If you are merging nodes of two parts, and you have set the Keep axis attribute to Yes for both parts, Tekla Structures creates a rigid link.
For this beam, type in 010. (Rigid link is wanted in mid beam.) For this brace, type in 100. (Rigid link is wanted at beam start point.)