3.7.2.1 BeamView
The "BeamView" component manages the display options for beams and trusses (refer to Fig. 3.7.2.1.1). This includes the visualization of cross-section forces, resultant displacements, the stress-to-strength ratio of materials, and axial stress.
In previous versions of Karamba3D, the term "utilization" was used in place of "Stress/Strength ratio". However, this caused confusion: the stress-wise utilization (or stress-to-strength ratio) only describes the condition at a specific point in the cross section. In contrast, the "Utilization of Elements" component calculates the overall utilization of the entire cross section, accounting for factors such as plastic behavior and buckling. Therefore, the stress/strength ratio and utilization values may differ for the same beam under the same loads.
The “Render Settings”-submenu
When enabled, the options for "Cross section," "Displacement," "Stress/Strength Ratio," and "Axial Stress" render a visual representation of the model. Utilization is calculated as the ratio of normal stress at a given point to the material's strength, with shear and buckling effects not considered.
The color range for the results spans from the minimum to the maximum values. Users can customize color ranges for all result quantities via the "Karamba3D/Settings" menu. Alternatively, predefined color ranges can be selected from the component's context menu: right-click on the component, navigate to 'Colors,' and choose a color range. A "Legend" component allows inspection of the corresponding values for each color.
The mesh used for rendering is accessible via the "Mesh" output of the "BeamView" component. Two sliders control the mesh resolution of rendered beams: the "Length/Segment" slider in the "ModelView" component sets the size of sections along the beam’s middle axis, while the "Faces/Cross section" slider in "BeamView" controls the number of faces per cross section. For circular hollow cross-sections, the "Faces/Cross section" value is multiplied by six to ensure a smooth visual appearance.
It is instructive to see which parts of a beam are under tension or compression. Activate the “Axial Stress”-checkbox in menu “Render Settings” in order to display the stresses in longitudinal beam direction. Red (like brick) means compression, blue (like steel) tension. In some models there may exist small regions with high stresses with the rest of the structure having comparatively low stress levels. This results in a stress rendering that is predominantly white and not very informative. With the sliders for “Upper Result Threshold” and “Lower Result Threshold” of the “ModelView” you can set the range of the color-scale (see section 3.6.1). Result values beyond the upper limit appear yellow, below the lower threshold green (see fig. 3.7.2.1.2).
Display of cross section forces and moments
The “Section Forces” sub-menu lets you plot section forces and moments as curves, meshes and with or without values attached. All generated curves and meshes get appended to the “BeamView”-component's “Curves” and “Mesh” output. The graphical representation is oriented according to the local coordinate axes of the beam and takes the deflected geometry as its base. The subscript of bending moments indicates the local axis about which they rotate, for shear forces it is the direction in which they act (see also fig. 3.7.2.1.3). The cross-section forces refer to the section which is defined by the element's local coordinate system. In fig. 3.7.8.4 the cross section forces need to be applied to the right side of the beam to be in equilibrium with the external point load since the local X-direction points to the left side.
The size of the cross section forces diagrams can be scaled separately for forces and moments by the two sliders in the "SectionForces"-menu.
Customize the mesh-colors of the cross section forces diagrams via "karamba.ini". The slider “Length/Subdivision” in sub-menu “Render Settings” of the “ModelView”-component controls the number of interpolation points.
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