Normal Stress
In a rectangular or Cartesian coordinate system (x,y,z), the stress tensor τ is given by:
(1)
where ix, iy and iz denote unit vectors in the x-direction, y-direction and z-direction, respectively. The components of τ may be interpreted thus:
- τxx is the x-component of force per unit area exerted across a plane surface element normal to the x-direction;
- τxy is the y-component of force per unit area exerted across a plane surface element normal to the x-direction; and so on. (Precisely analogous interpretations can be given to components of stress in any orthogonal coordinate system.)