Visualization of Stresses
Stress color maps and stress contours can be viewed for any model for which a solution exists. To enter the stress visualization panel, select Stresses from the Visualize menu. This will bring up the panel shown below (the project "test_2_3_skew" that is used as an example here is installed with EverFE2.23). Note that you cannot change any model parameters when in the visualization panel. To return to EverFE's input panels when you are done viewing stresses, select Return to Model Builder option from the Visualization menu.
Figure 1: Visualization of stresses
The plan view will now show the upper-left slab in tan, and a horizontal red line appears in the elevation view as shown below in Figure 2. You can select any slab or combination of slabs for which you want to view stresses by clicking on a slab in the plan view, which turns its color from gray to tan. Clicking on a selected slab will de-select it. The horizontal red line in the elevation view indicates that you are viewing stresses in an x-y plane. Alternatively, you can select view stresses in the y-z or x-y plane, although the x-y plane is often most useful.
Figure 2: Plan and Elevation when Viewing Stresses
The entry box entitled Horizontal (Slab) at the upper right of the stress viewing panel defaults to the plane defining the top of the slabs (7). In this model, there are two elements through the thickness of the slab, and one through the thickness of the base layer, which implies that there are eight x-y planes in which nodes exist: planes 3-7 are in the slab, with 3 at the bottom and 7 at the top, and 0-2 are in the base, with 0 at the bottom of the model and 2 at the top of the base. Toggling through these planes will move the horizontal red line shown in the elevation view to the corresponding position.
There are eight stress values that can be viewed, which are selected via the corresponding check-buttons in the Stress to View portion of the panel: Max principal (the default), Min principal, and the six individual stress components. The scaling can be set to global, which scales the color maps in the context of the largest and smallest stresses the exist at any point in the model, or local (the default), which sets the scale limits based only on the stresses in the selected slabs. You can choose to view either a color map (recommended) or a contour map of the selected stress by checking the appropriate selection box.
Clicking on the View Stresses button will open a visualization window in which the color map or stress contours will be drawn. Selecting all six slabs for our example "test_2_3_skew" and clicking View Stresses gives the color map shown in Figure 3. Note that the wheel loads are shown as small open black rectangles.
Figure 3: Max Principal Stresses on Top of All Slabs
The default view depicts the top of the slabs in plan, with the peak stress of 0.948 MPa occurring in the top right slab. This is not surprising, since this slab is significantly longer than the others, and this model includes the effect of a negative temperature gradient that will produce large tensile stresses at the top of long slabs. De-selecting the five slabs other than the critical upper-right slab selecting and clicking View Stresses again gives the view shown in Figure 4.
Figure 4: Max Principal Stresses on Top of Critical Slab
The stress color maps are actually 3D images, and support zooming in and out as well as rotation in space. Zooming in can be accomplished by right-clicking the mouse in the visualization window above the window centerline, and zooming out is accomplished by right-clicking below the window centerline. The rate of zoom is controlled by the distance of the mouse-click from the window centerline. Rotation is accomplished by left-clicking in the stress window. Figure 5 shows a rotated view of the same color map pictured in Figure 4; note that the outline of the slab is drawn as a black wire frame to help maintain perspective. If you ever get "lost" while rotating a view, simply click on the View Stresses button and the model will snap back to the original orientation and scale.
Figure 5: Rotated and Scaled View of Max Principal Stresses
Note: Closing the visualization window will shut down EverFE. However, to reduce desktop clutter, you can minimize the visualization window when you no longer need it.