The advantage of interpolated distribution is compliance with the distribution of a refined mesh. The disadvantage is that this distribution does not correspond exactly with the calculation result. Therefore, it is important always to use a refined mesh for the analysis of critical points. For example, when using a plastic material, the real plastic limit stress is displayed correctly only if you select the "Constant on elements" option.
Smoothing Options
Just as in the RFEM Display Navigator, you can set the distribution of internal forces in surfaces in RF‑STEEL Surfaces. Since deformations are always the result of the FEM calculation, the corresponding forces will be recalculated. This means that the internal forces on an FEM element are calculated depending on the composition (triangular or square) in three or four places. In order to obtain continuous internal forces and thus a smoothed distribution, these internal forces have to be interpolated. Interpolation is done by selecting the "Distribution of internal forces" option in the surfaces.
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Mr. Günthel provides technical support for our customers.
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The limit stresses in RF‑/STEEL can be user-defined for each thickness range.
The support conditions of a beam subjected to bending are essential for its resistance to lateral-torsional buckling. If, for example, a single-span beam is held laterally in the middle of the span, the deflection of the compressed flange can be prevented, and a two-wave eigenmode can be enforced. The critical lateral-torsional buckling moment is increased significantly by this additional measure. In the add-on modules for member design, different types of lateral supports on a member can be defined using the "Intermediate supports" input window.
This technical article analyzes the effects of the connection stiffness on the determination of internal forces, as well as the design of connections using the example of a two-story, double-spanned steel frame.
A site joint consisting of hollow sections with end plates will be designed. It is the bottom chord of a truss that has to be divided for transport reasons.
- General stress analysis
- Automatic import of internal forces from RFEM/RSTAB
- Complete graphical and numerical results of stresses and stress ratios integrated in RFEM/RSTAB
- Wide range of customization options for graphical output
- Flexible design in multiple design cases
- Clearly arranged result tables for a quick overview after the design
- High productivity due to the minimal amount of input data required
- Flexibility due to detailed setting options for basis and extent of calculations
- Cross-section optimization
- Transfer of optimized sections to RFEM/RSTAB
- Design of any thin-walled cross-section from SHAPE-THIN
- Representation of a stress diagram on a section
- Determination of normal, shear, and equivalent stresses
- Stress results of individual internal forces types
- Detailed representation of stresses in all stress points
- Determination of the largest Δσ for each stress point (for example, for fatigue design)
- Colored display of stresses and design ratios for a quick overview of the critical or oversized zones
- Parts lists and quantity surveying
- Determination of principal and basic stresses, membrane and shear stresses, as well as equivalent stresses and equivalent membrane stresses
- Stress analysis for structural surfaces including simple or complex shapes
- Equivalent stresses calculated according to different approaches:
- Shape modification hypothesis (von Mises)
- Shear stress hypothesis (Tresca)
- Normal stress hypothesis (Rankine)
- Principal strain hypothesis (Bach)
- Optional optimization of surface thicknesses and data transfer to RFEM
- Serviceability limit state design by checking surface displacements
- Detailed results of individual stress components and ratios in tables and graphics
- Filter function for surfaces, lines, and nodes in tables
- Transversal shear stresses according to Mindlin, Kirchhoff, or user-defined specifications
- Parts list of designed surfaces
In order to facilitate the data input, surfaces, members, sets of members, materials, surface thicknesses, and cross-sections are preset. It is possible to select the elements graphically using the [Select] function. The program provides access to the global material and cross-section libraries.
Load cases, load combinations, and result combinations can be combined in various design cases.
The combination of surface and member elements and separate designs allows you to model and analyze only critical parts, such as frame joints, using surface elements. The other parts of the model can be designed using member analyses.
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