Using the Timber Design add-on, timber column design is possible according to the 2018 NDS standard ASD method. Accurately calculating timber member compressive capacity and adjustment factors is important for safety considerations and design. The following article will verify the maximum critical buckling strength calculated by the Timber Design add-on using step-by-step analytical equations as per the NDS 2018 standard including the compressive adjustment factors, adjusted compressive design value, and final design ratio.
The fatigue design according to EN 1992-1-1 must be performed for the structural components subjected to large stress ranges and/or many load changes. In this case, the design checks for the concrete and the reinforcement are performed separately. There are two alternative design methods available.
RWIND 2 and RFEM 6 can now be used to calculate wind loads from experimentally measured wind pressures on surfaces. Basically, two interpolation methods are available to distribute pressures measured in isolated points across the surfaces. The desired pressure distribution can be achieved using the appropriate method and parameter settings.
Using an example of a steel fiber-reinforced concrete slab, this article describes how the use of different integration methods and of a different number of integration points affects the calculation result.
The Geotechnical Analysis add-on provides RFEM with additional specific soil material models that are able to suitably represent complex soil material behavior. This technical article is an introduction to show how the stress-dependent stiffness of soil material models can be determined.
In RFEM 6, the results for the FE mesh nodes are determined using the finite element method. For the distribution of internal forces, deformations, and stresses to be continuous, these nodal values are smoothed through an interpolation process. This article will introduce and compare the different types of smoothing that you can use for this purpose.
With the most recent ACI 318-19 standard, the long-term relationship to determine the concrete shear resistance, Vc, is redefined. With the new method, the member height, the longitudinal reinforcement ratio, and the normal stress now influence the shear strength, Vc. This article describes the shear design updates, and the application is demonstrated with an example.
In RFEM 6, it is possible to define line welds between surfaces and calculate the weld stresses using the Stress-Strain Analysis add-on. This article will show you how to do it.
The stand-alone program RSECTION is at your disposal for determining section properties and performing stress analysis for thin-walled and massive cross-sections. The program can be connected to both RFEM and RSTAB so that sections from RSECTION are also available in the RFEM and RSTAB library. Likewise, internal forces from RFEM and RSTAB can be imported into RSECTION.
You can use the stand-alone program RSECTION to determine the section properties for any thin-walled and massive cross-sections, as well as to perform a stress analysis. The previous Knowledge Base article titled "Graphical/Tabular Creation of User-defined Cross-sections in RSECTION 1" discussed the basis of defining cross-sections in the program. This article, on the other hand, is a summary of how to determine the section properties and perform a stress analysis.
The advantage of the RFEM 6 Steel Joints add-on is that you can analyze steel connections using an FE model for which the modeling runs fully automatically in the background. The input of the steel joint components that control the modeling can be done by defining the components manually, or by using the available templates in the library. The latter method is included in a previous Knowledge Base article titled “Defining Steel Joint Components Using the Library". The definition of parameters for the design of steel joints is the topic of the Knowledge Base article “Designing Steel Joints in RFEM 6".
RSECTION 1 is a stand-alone program for determining section properties for both thin-walled and massive cross-sections, as well as for performing a stress analysis. In addition, the program can be connected to both RFEM and RSTAB: sections from RSECTION are available in the RFEM/RSTAB libraries, and internal forces from RFEM/RSTAB can be imported into RSECTION.
RFEM 6 includes the Form-Finding add-on to determine the equilibrium shapes of surface models subjected to tension and members subjected to axial forces. Activate this add-on in the model's Base Data and use it to find the geometric position in which the prestress of lightweight structures is in equilibrium with the existing boundary conditions.
Structures are three-dimensional in reality; however, they can be simplified and analyzed as 2D or 1D models. The model type has a crucial influence on how the structural components are stressed, and it should be defined prior to modeling and calculation.
In RFEM, you can create screw lines using the "Trajectory" type line. To do this, you need a center line/guide line around which the line can be modeled, as well as a start and end point. Then, you can create a "Trajectory" type line between the start and end points; this initially appears as a straight line.
Very small torsional moments in the members to be designed often prevent certain design formats. In order to neglect them and still perform the designs, you can define a limit value in RF‑/STEEL EC3 from which torsional shear stresses are taken into account.
The RF‑/STEEL EC3 add-on module can perform the design of fillet welds for all parametric, welded cross-sections of the cross-section library. For this, the option must be activated in the detail settings of the module. As an alternative, you can also use a surface model for the design.
This article deals with the determination of the concrete reinforcement for a beam stressed by tension only according to EN 1992-1-1. The aim is to show the tensile load of a member-type element (without imposed deformations) and to define the concrete reinforcement in accordance with the standard's construction rules and provisions using the RFEM structural analysis software.
With the SHAPE‑THIN cross‑section properties software, you can create any thin‑walled cross‑section and use it in RFEM or RSTAB as a member cross‑section. SHAPE‑THIN can give all relevant cross‑section values of any cross‑section for a design and stress analysis.
Often, it happens that stress peaks occur on a nodal support that is attached to a surface. You can avoid such singularities by modeling the nodal support as a column.
In RFEM 5 and RSTAB 8, it is possible to assign nonlinearities to member hinges. In addition to the nonlinearities "Fixed if" and "Partial activity", you can select "Diagram". If you select the "Diagram" option, you have to specify the according settings for the activity of the member hinge. For the individual definition points, it is necessary to specify the abscissa and ordinate values (deformations or rotations and the according internal forces) that define the hinge.
With the orthotropic elastic-plastic material model, you can calculate solids with plastic material properties in RFEM 5 and evaluate them according to the Tsai‑Wu failure criterion. The Tsai-Wu criterion is named for Stephen W. Tsai and Edward M. Wu, who published it in 1971 for plane stress states.
The elastic‑plastic material model in RFEM 5 allows you to calculate surfaces and solids with plastic material properties and to carry out a stress evaluation. This material model is based on the classic von Mises plasticity.
The determined values for the influence ordinates are displayed as decimal numbers with up to six decimal places by default. This is usually sufficient for the influence lines of internal forces.
With the nonlinear elastic material model in RFEM 5, you can calculate and carry out a stress analysis of surfaces and solids with nonlinear material properties.
Until now, if you wanted to determine the centroid of a rectangle, it was necessary to define a line from one corner point to the diagonally opposite point. You obtained the centroid by dividing this line. In RFEM 5 and RSTAB 8, you now have the possibility to create a node between two points. Thus, it is sufficient to select the corner points; then you can determine the distance in absolute or relative values.