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# 8.18 Surfaces - Basic Stresses

To control the graphical display of the basic stresses, select Surfaces → Stresses in the Results navigator. Table 4.18 shows the basic stresses of surfaces in numerical form.

The table shows the basic stresses sorted by surfaces. The results are listed in reference to the grid points of each surface.

Grid Point

The numbers of the grid points are listed by surface. For more information about grid points, see Chapter 8.13.

Grid Point Coordinates

Table columns B to D show the coordinates of grid points in the global coordinate system XYZ.

Basic stresses

The stresses are related to the directions of the local surface axes. When you analyze curved surfaces, they refer to the local axes of the individual finite elements (see Figure 8.41).

The basic stresses are shown in Figure 8.42 and have the following meanings:

 σx,+ Stress in the direction of the local axis x on the positive side of the surface (i.e. side in direction of positive surface axis z) where d: thickness of surface σy,+ Stress in the direction of the local axis y on the positive side of the surface (i.e. side in direction of positive surface axis z) σx,− Stress in the direction of the axis x on the negative side of the surface σy,− Stress in the direction of the axis y on the negative side of the surface τxy,+ Torsional stress on the positive side of the surface τxy,− Torsional stress on the negative side of the surface τxz Shear stress orthogonal to the surface in the direction of the axis x where d: thickness of surface τyz Shear stress orthogonal to the surface in the direction of the axis y