This window is displayed when you create a new section or open an existing section. It is displayed as a floating window separate from the main application window. Closing this window will not close the section itself and will not lose any information about the section. To redisplay this window (when a section is open), select Section Inputs from the View menu, or press F3.
Parts are made up of elements, each defining the geometry and behavior of a flat segment of the shape. This tab contains the inputs for elements, one part at a time. See also Section Tab, Part Tab, and Elements Tab.
| Use Direct Strength | Check this box to use the Direct Strength Method of calculating section strength according to the AISI Specification. You must compute the elastic buckling behavior and enter the corresponding direct strength parameters in the table. You may use the Elastic Buckling feature from the Compute menu for sections consisting of one part. This tool allows you to select points directly from the buckling plot and transfer the values into the table. |
| Prequalified Section | Check this box if the section complies with the geometric parameters of prequalified sections as defined in the Direct Strength provisions of the AISI Specification. The strength of non-prequalified sections is determined using the safety or resistance factors for rational engineering analysis. |
| Generate | This button can be used to automatically generate the critical elastic buckling load ratios for compression and bending. This uses the Finite Strip Method for a variety of half-wavelengths to identify the critical local buckling and distortional buckling loads. This feature is available for sections comprised of one part, with or without holes. If changes are made to the section, the Generate button should be used again to recalculate the load ratios. |
| Pcrl/Py | The ratio of the critical elastic local buckling load to the compressive yield load. A value of 0 causes CFS to revert to the Main Specification provisions even if you check the box to Use Direct Strength. |
| Pcrd/Py | The ratio of the critical elastic distortional buckling load to the compressive yield load. A value of 0 causes CFS to revert to the Main Specification provisions even if you check the box to Use Direct Strength. |
| Note: Py is based on the gross section area and the specified longitudinal compression yield stress. | |
| Mcrl/My | The ratio of the critical elastic local buckling moment to the yield moment. A separate value is required for each direction of bending. A value of 0 causes CFS to revert to the Main Specification provisions even if you check the box to Use Direct Strength. |
| Mcrd/My | The ratio of the critical elastic distortional buckling moment to the yield moment. A separate value is required for each direction of bending. A value of 0 causes CFS to revert to the Main Specification provisions even if you check the box to Use Direct Strength. |
| Note: My is based on the gross section modulus for the extreme fiber and the specified longitudinal compression yield stress. | |
| Vcr/Vy | The ratio of the critical elastic shear buckling force to the shear yield force. A separate value is required for vertical and horizontal shear. A value of 0 causes CFS to revert to the Main Specification provisions even if you check the box to Use Direct Strength. |