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005690

2024-08-08

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Overview

Introduction

Theory

Input Data

Calculation

Results

Sections

Sections can be applied to the surfaces of the model. They enable you to display parts of the result meshes and obtain local results, for example, a drag force acting on the section. These results can be examined for any part of a model, that is, for any subset of model triangles.

By means of sections, you can also control which parts of the topology are displayed. The parts can be shown exclusively or hidden, similarly to the "Visibility" options available in RFEM 6 / RSTAB 9.

The sections are managed in a separate tab of the navigator. By default, sections are created automatically for the zones, each representing a material or a part (see Chapter Zones).

Sections with Zones to Control Visibility

To also use the zones for the results, it is necessary to create mesh sections. Click the button. In the menu, select the "Generate Mesh Sections" option. The "Section Options" dialog box appears. Click the button and then close the dialog box.

Generating Sections from Zones

Now, you can select a zone in the "Mesh Sections" list and examine its surface quantity results.

Surface Pressure of Wall Mesh Section

For each zone in the "Mesh Section," there are "Display Options" in the "Edit Bar" menu.

Zone, Display Options

Here you can easily display the "Drag Force" or the "Mesh Section Information" for the zone, see the image Display Options.

Mesh Section Information

The Mesh Section Information window contains basic information about the zone, the size of the area, and the number of triangles in the area. Then, there are the results of the "Drag Force" quantities, the resultant force (F), and its components (Fx, Fy, Fz).

Next, There are values on the triangles of the surface mesh. The mesh section is divided into triangles, each triangle has "front" and "back" values that may be different.

Part of Model Surface Mesh, Set of Triangles

The "netto" value of the quantity (p^N) is calculated as the weighted average of the (p^N) values calculated for each triangle belonging to the zone, calculated from the (p⁺) value on the front side and the (p^-) value on the back side of the triangles. The average value calculated over all triangles of the mesh section is given by the formula:

P = \frac{\sum_{i} P_{i} \cdot A_{i}}{\sum_{i} A_{i}}

P	is average pressure
P_i	is pressure on triangle

Average Value of Pressure

Furthermore, the C_p^N coefficients, shear stress T^N, and the maximum and minimum values of those quantities (such as Max p^N, Min p^N, Max T^N, Min T^N, and so on) are shown. The maximum/minimum values are the maxima/minima of the variables on the front/back of each triangle belonging to the zone, e.g. Max C_p⁺ is the max value of Cp in front side of each triangle belonging to the zone.

Important

When using the "export surface thickness" option in RFEM 6, you get a completely different scenario regarding the "back and front" values. The model then has two walls (inside and outside wall), see image below, each wall has front and back values, the back values are inside the wall and have a value of 0.

Wall With and Without Thickness

Geo Sections

Each model – primary or secondary – represents a Geo section. They are available when selecting the "Model" tab of the work window. Use the button to create sections and work with them.

Functions Commands for Geo-Sections

Mesh Sections

The mesh sections represent all zones that were created automatically or defined manually (see Chapter Zones). They are available when selecting the "Zones" tab of the work window. To modify or delete sections, use the button.

Section Manager - Mesh Sections

Parent Chapter

Display Options