Use this option to define code parameters of aluminum member type. There are two ways to access this option:
- Click the New member type option in the Member Type dialog
- Click the Parameters button in the Definitions dialog dialog.
The following dialog displays:
The Member type field displays the name of the selected member type (enter any member type name). The Buckling with respect to Y / Z axis fields displays the length of the member for the required plane. There are two ways to define the length:
- Select the Real option, the introduced value is interpreted directly as the length in question
- Select the Coefficient option, the introduced value is interpreted as the coefficient by which the real member length should be multiplied to obtain the length in question. For instance, introducing the value 0.25 means that the length in question equals ¼ of the real length.
Choose the Coefficient option to define simultaneous members whose real length values differ, while their supports are distributed in the same manner. If the set parameters are to be saved as a category, it is necessary to select this procedure of length definition. Introducing the value 1.0 guarantees that each member defined by means of the category as Ly will assume its real length.
The Buckling length coefficient field defines the buckling length coefficients of a member in both directions. The real member length (i.e. the sum of component member lengths) is introduced automatically in the relevant fields.
Buckling length coefficient depends on the end-support condition of the bar nodes in the buckling plane. The Buckling length is also defined in the Buckling Diagrams dialog, opened by clicking the icon representing the selected buckling model type. After selecting one of typical schemes, the coefficient value will be accepted or calculated automatically.
The icons in the dialog are divided into two groups:
- The first group contains typical (code) methods of member support and corresponding values of buckling coefficients,
- The second group contains icons of options used for calculating buckling coefficient for columns of multi-story frames. The colors of the icons represent: red (A) - calculations for sway frames, blue (B) - for non-sway frames.
Buckling is always considered in calculations if a compression force appears in the member, even if it is negligible in comparison to the other internal forces. A separate analysis is not performed that would determine if buckling effects should be disregarded. To eliminate buckling effects from the calculations, the last icon must be chosen. If selected, buckling will be disregarded in the calculation process.
Options used during lateral buckling verification (lateral buckling length coefficient) are selected in the Lateral Buckling Parameters field. Selecting the appropriate icon opens the dialog for defining relevant parameters.
Lateral buckling calculations requires you to provide for a bar the distance between sections blocked against twisting (lateral buckling length). It is necessary to distinguish two buckling lengths (for the upper and for the lower flange) as it is possible to attach the upper and lower flanges separately, which results in the appearance of different load cases of compression forces. You should provide the value of the coefficient by which the base bar length is multiplied to obtain the lateral buckling length. The length IZ is taken as the base length. The coefficient value may be entered directly or by selecting the icon representing typical attachment case for which the coefficient will be automatically chosen.
Click the More button to open an additional dialog. You can then define the remaining bar type parameters described in the code, such as: load type, section parameters, etc.
Click the Service button to open an additional dialog. You can define the parameters of bar type (limit displacements, initial deflection).
Click the Save button to add a bar type (with defined name and parameters) to the list of predefined aluminum bar types.