Stress tensors
Stress Tensors are represented pictorially as stress vectors acting on a cube. This cube represents an infinitesimal volume of material at a point on the surface or in the interior of a body:
Stress tensors are identified using a two-letter designation (such as XX or YZ). The letters represent the global axis directions. The first letter indicates the direction normal to a stress cube face. The second letter indicates the direction of the stress vector.
There are nine tensor components for 3D stresses:
- Normal XX
- Normal YY
- Normal ZZ
- Shear XY
- Shear YZ
- Shear ZX
- (Shear YX)
- (Shear ZY)
- (Shear XZ)
However, the three additional components (YX, ZY, and XZ) are equivalent to the XY, YZ, and ZX components, respectively, so there are only six unique tensor values.