Answer:
By default, the computation kernel of the cross-section program SHAPE‑THIN is used in the RF‑/ALUMINUM add‑on module to determine the stresses of the effective cross-section in an iterative procedure. This method is precise, as all corners and edges of the cross-section are covered, but can be very time-consuming in the case of compound cross-sections.
As an alternative, it is possible to determine the effective cross-section using the simplified analytical method (see Image 01), which is significantly faster. With this approach, corners, roundings, and so on are neglected and compensated by a factor at a later stage. No iterative calculation is performed. Therefore, the effective cross-section values might be higher than with the SHAPE‑THIN calculation.
In such a case, we recommend carrying out the calculation using the analytical method, then only designing the governing structural component with the governing load combination using the SHAPE‑THIN solution.
