Creating a validation example for Computational Fluid Dynamics (CFD) is a critical step in ensuring the accuracy and reliability of simulation results. This process involves comparing the outcomes of CFD simulations with experimental or analytical data from real-world scenarios. The objective is to establish that the CFD model can faithfully replicate the physical phenomena it is intended to simulate. This guide outlines the essential steps in developing a validation example for CFD simulation, from selecting a suitable physical scenario to analyzing and comparing the results. By meticulously following these steps, engineers and researchers can enhance the credibility of their CFD models, paving the way for their effective application in diverse fields such as aerodynamics, aerospace, and environmental studies.
As for the previous generations of Dlubal programs, an integrated interface with Autodesk Revit is now also available for RFEM 6 and RSTAB 9. This article will provide some general information about the interface as well as the Dlubal-relevant structural objects and parameters in Revit.
Nodal releases are special objects in RFEM 6 that allow structural decoupling of objects connected to a node. The release is controlled by the release type conditions, which may also have nonlinear properties. This article will show the definition of nodal releases in a practical example.
Line releases are special objects in RFEM 6 that allow structural decoupling of objects connected to a line. They are mostly used to decouple two surfaces that are not rigidly connected or transferring only compressive forces at the common boundary line. By defining a line release, a new line is generated at the same place which transfers only the locked degrees of freedom. This article will show the definition of line releases in a practical example.
In the RFEM 6 and RSTAB 9 programs, it is possible to group objects based on different criteria. Hence, objects that meet the defined criteria can be selected and edited at the same time. This is possible with the “Object Selection” tool, which is comparable to “Special Selection” in RFEM 5. This article will show you how to group objects with “Object Selection" as a new guide object of RFEM 6 or RSTAB 9.
In RFEM 6 it is possible to save selected objects (as well as whole structures) as blocks and reuse them in other models. Three types of blocks can be distinguished: non-parameterized, parameterized, and dynamic blocks (via JavaScript). This article will focus on the first block type (non-parameterized).
This article compares the design to the one in the referenced article: Design of Concrete Columns Subjected to Axial Compression with RF-CONCRETE Members. It is, therefore, about taking exactly the same theoretical application carried out in RF-CONCRETE Members and reproducing it in RF-CONCRETE Columns. Thus, the objective is to compare the different input parameters and the results obtained by the two add-on modules for the design of column-like concrete members.
If you want to consider guide objects in the overall view (F8 key or double-click on the mouse wheel) or, for example, in a particular direction of the views, you can enable this option in the settings of the particular guide objects (guidelines, background layers, line grids).
With the "Info About Object..." function available in the menu under "Tools", you can display all the information about an object by placing the cursor on it in the graphical window.
In RFEM, you can display the contact properties between two surfaces by means of contact solids. Among other things, you should ensure that both contact surfaces of a contact solid have the same integrated objects. Therefore, when modeling the contact surfaces, we recommend using the copy function in order to create the second contact surface.
RFEM and RSTAB save the input data, the FE mesh, the results, the printout reports, and the 3D gITF model preview, including all visual objects, in one file.
When calculating foundations according to EC 7 or EC 2, different foundation types or sizes are usually used in one object. However, boundary conditions like the soil parameters, the materials for foundations, concrete covers, and the load combinations selected for design remain the same for all foundations, as a rule.
If you want to remove redundant nodes but keep connected objects, you can right-click the relevant node and select the "Delete Nodes" and "Merge Connected Members" options. In addition to members, you can also merge lines in RFEM.
The new "Result Beam" member type in RFEM 5 allows you to determine the load sums of individual floors easily. To do this, model a member in the relevant floor or in all floors, then specify the relevant walls as inclusive objects in the parameters of the result beam. RFEM then integrates the surface internal forces into member internal forces.
In RFEM, surfaces are automatically connected if they have common boundary lines. If the definition line of a surface is lying in another surface, the line is automatically integrated into the surface, provided that it is a planar surface. For quadrangle surfaces, however, automatic object detection would be relatively time-consuming. For this reason, the corresponding function is deactivated. The integrated objects must be specified manually.
You can assign comments to each element in RFEM and RSTAB (structure element, load element, and so on). This can help to improve the overview and documentation of structures, as the comments appear in the printout report and, for example, certain objects can be filtered and displayed using the "Select Special" function.
Model and load objects can be defined graphically or in tables, or they can be created using parameters (see the manual). With this parameterized input, you can also access the cells of certain tables of the program. In this way, it is possible to link a load parameter with a model data parameter, for example. The reference is created by the $ sign.
In RFEM 5 and RSTAB 8, you can add visual objects to the model in order to make a convincing impression on your client when presenting the structural model. These objects allow both laypersons and engineers to better understand the dimensions of the system.
In RFEM and RSTAB, you can add a comment to model objects in the graphic. When inserting a comment, the origin of the current work plane automatically jumps temporarily to the same plane in which the comment is placed. This prevents comments from being accidentally placed very far from the object.
Friction plays an important role in practice. Without friction, the brakes of cars would be useless, objects on inclined planes would just slide away, and prestressed bolt connections would be impossible.
To determine the distance between two nodes or the angle between two objects without using the dimensioning function, you can simply use the "Measure" option on the "Tools" menu. Here, you can also choose between various measure functions.
In RFEM and RSTAB, you can use many interfaces to simplify the modeling of your structure. From background layers, to the import of IFC objects that can be converted into members or surfaces, to the import of the entire structural system from Revit or Tekla. Regardless of the performance of the selected interface, further utilization also depends on the accuracy of the imported data.
This article describes how to determine the contact force between two objects behaving like walls that are diagonally inclined at a certain angle on top of each other. Define a nodal release to determine this contact force. Since a nodal release requires certain conditions, this article shows two examples.