Knowledge Base

When evaluating results in RFEM 6, it is possible to define a zone in the model where the graphical results are represented by mean values instead of the actual diagrams. In other words, you can evaluate the smoothed surface internal forces and moments or set them to zero, thus preventing singularities. In RFEM 6 this option is called “Surface Results Adjustments”, and it corresponds to the "Average Region" implemented in RFEM 5.

When evaluating results in RFEM 6, it is possible to define a zone in the model where the graphical results are represented by mean values instead of the actual diagrams. In other words, you can evaluate the smoothed surface internal forces and moments or set them to zero, thus preventing singularities. In RFEM 6 this option is called “Surface Results Adjustments”, and it corresponds to the "Average Region" implemented in RFEM 5.

Author: Diego APELLÁNIZ

B+G Ingenieure Bollinger und Grohmann GmbH; Alt-Moabit 103, 10559 Berlin; [email protected]

The Parametric FEM Toolbox is a plugin developed by the author in collaboration with Bollinger + Grohmann that implements the RF-COM API of the finite element software Dlubal RFEM in the visual programming environment of Grasshopper in order to establish a connection between these two platforms. Both the transfer of data from Grasshopper into RFEM and back from RFEM into Grasshopper are supported. Thus, new possibilities beyond the options of the conventional graphical user interface (GUI) of RFEM are enabled: the use of the Rhino 3D-Modelling tools to create NURBS curves and surfaces, the possibility to parametrically modify an existing FE-Model or part of it, the export and process of data of a FE-Model which sometimes is not even available through the program GUI such as the 3D shapes of beam elements, etc. Due to these functionalities and its object-oriented structure and compact graphical user interface, this tool can easily be adapted to numerous workflows and optimization processes.

Parametric input provides you with an efficiency-increasing tool for creating and editing models. In this case, the structure depends on certain variables (length, width, load, and so on), also called parameters. This article will summarize the advantages of working with parameterized models in RFEM 6 and RSTAB 9.

Member transverse stiffeners are available as an option when editing members in RFEM 6 and RSTAB 9. They can be taken into account when verifying the shear resistance of web plates in order to limit the buckling fields. In RFEM 6 and RSTAB 9, member transverse stiffeners are organized as “Type for Members” (Image 1).

Line welded joints are a useful program feature allowing the calculation of weld stresses between surfaces in RFEM 6. Hence, if a weld is defined for a line in a surface model, the stresses of this weld can be determined with the "Stress-Strain Analysis" add-on. This new feature is available in the Types for Lines entry of the Navigator.

The second part of the two-part add-on Optimization & Costs / CO₂ Emission Estimation enables the estimation of CO₂ emissions for structural models. This article shows you how to do it by estimating the CO₂ emissions for the building shown in Image 1.

In addition to finding suitable parameters for parameterized models and blocks via the artificial intelligence (AI) technique of particle swarm optimization (PSO), the two-part add-on Optimization & Costs / CO₂ Emission Estimation estimates the model costs or CO₂ emissions for structural models.

An aluminum member section comprised of slender elements may experience local buckling failures of its flanges or web before the member can reach its full strength. In the Aluminum Design add-on, there are three options available for determining the nominal flexural strength, M_nlb for the limit state of local buckling when designing according to the 2020 Aluminum Design Manual [1].

Optimization is a process in the RFEM and RSTAB programs that takes place parallel to the actual model calculation. It can be considered as a step following parameterization, since it is assumed that the model or block is built with a parametric input and is controlled by global parameters of the 'optimization' type.