Common beam parameters
Some of 1D member parameters that define the properties of a 1D member are common for all beam types.
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The name of the 1D member. |
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The type of the 1D member, used within the Structural Model. |
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| Analysis model | Specifies if the 1D member is standard one or cellular beam. |
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The cross-section influences the properties of a 1D member and defines its shape and also material (as the material is one of cross-section properties). |
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This angle determines the rotation of the cross-section of the inserted 1D member around the longitudinal axis of the 1D member. |
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The 1D member is inserted by means of two insertion points. This property item determines the position of the insertion points on the cross-section of the 1D member. |
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The eccentricity is similar to the previous feature. However, while the Insertion point item only allows for positions of the insertion point in certain characteristic points of the cross-section, the Eccentricity provides for an arbitrary position of the insertion point. |
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This item specifies the way the local axes of the 1D member are determined. |
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This value defines the rotation of local axes of the 1D member. The rotation is measured around the 1D member longitudinal axis, i.e. X-axis. |
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This item says which type of finite element will be used for the 1D member. |
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Buckling length |
Buckling length for individual directions may be specified on each 1D member. For more information see chapter Buckling parameters. |
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Any entity including a 1D member can be put into a layer. The layer can thus comprise entities that have something in common (e.g. one floor, columns of one floor, columns of the same length, etc.) Once layers are defined and assigned, they can be used to e.g. display just a particular part of the structure, make selection of that particular part, etc.) |
Name
The name is used mainly for a unique identification of 1D members (or all entities in general). The name can be displayed on a screen, printed in output documents, used for selections, etc. For example, the name together with an advanced feature of the program command-line can be used for very fast multiple selection of all 1D members whose name starts with the same letter or letters (e.g. SEL B1? selects all 1D members whose name consists of letter B and a number within the range from 10 to 19).
The name is typed as a simple text.
Type
The (structural) type of a member is used to prioritise members within the structural model. There is also possible to display each type in different colour in a graphical window, Picture Gallery and Document pictures.
For more information about the structural model and the type see chapter Structural model.
Cross-section
The 1D member shape is defined by the selected cross-section type. Beams of "general beam", "column" and "horizontal beam" type have got a constant cross section over their length. On the other hand, "haunch beams" and "arbitrary beams" can have the cross section variable along the longitudinal axis.
The orientation of the cross-section in the 1D member local co-ordinate system can be adjusted via angle Alpha (see below).
The appropriate cross-section can be:
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either selected from a list of already defined cross-sections,
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or defined as a new cross-section in the project via the [Cross-section manager] button.
Alpha
This parameters defines the inclination of the cross-section Z-axis from the beam local Z-axis. This parameter together with "LCS rotation" provide for an arbitrary "positioning" of a cross-section in a model.
The angle is input in the pre-adjusted angle unit that is shown in square brackets in the corresponding table cell.
Member system line at
By default, a 1D member is inserted into the model by the end points of its midline. The user, however, may decide to insert the 1D member by any of outer corners of the 1D member cross-section. This option is useful when an eccentricity is to be introduced and it coincides with the outer dimensions of the cross-section.
The required Insertion point can be selected from a list of available option.
Eccentricity
If required, an eccentricity may be input in order to provide for more precise definition of structure shape. The eccentricity is defined in the definition axes of the cross-section.
The eccentricity is defined by two values: eccentricity in Y-direction and eccentricity in Z-direction. Both values are input into the appropriate table cells in units that have been pre-adjusted in project settings and that are shown in square brackets in the table cells.
Tip: If the eccentricity value is such that the "eccentric insertion point" coincides with an outer corner of the cross-section, the eccentricity may be defined simply by means of the "Insertion point" parameter (see above).
Local co-ordinate system (LCS)
Each 1D member has got its local co-ordinate system. The user can define the orientation of the system’s Y and Z axes. There are several options:
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to accept the default standard setting - see chapter Beam co-ordinate system. After certain geometrical manipulations the LCS parameter is set to "z by vector" in order to prevent unintentional rotation of the member LCS.
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to define the orientation of Y-axis either by a vector or by a point that the axis passes through,
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to define the orientation of Z-axis either by a vector or by a point that the axis passes through.
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to specify that the 1D member local Z-axis is parallel to the Z-axis of the current UCS. Note: When this option is selected, the local co-ordinate system is adjusted accordingly and the LCS parameter is set to "z by vector".
LCS rotation
Sometimes it may be convenient to rotate the local co-ordinate system. For example, if the user wants to define some load acting in a general direction and introduce it in 1D member local co-ordinate axes.
The angle defines the rotation of the local co-ordinate system around the X-axis of the same system.
The angle is input in the pre-adjusted angle unit that is shown in square brackets in the corresponding table cell.
FEM type
From the finite element analysis point of view, the 1D member can act like a standard 1D member or like a hinged (pinned) rod. The difference is that the standard 1D member is capable of transferring all the internal forces, while the latter variant only provides for transferring of the axial force.
The required option can be selected from a provided list.
Layer
Each 1D member can be "put into" a specific layer. The layer, that could be called group, thus can comprise such 1D members that will be in the future treated simultaneously. A good and well thought out grouping of 1D members in layers can significantly facilitate the manipulation with the model, including even the evaluation of results. And what’s more, a professional use of layers may save a lot of the user’s valuable time.
The required layer may be selected from a list of already defined layers. Or, a new layer may be defined for the 1D member.