Page 314 - Introduction to Continuum Mechanics

298 The Elastic Solid

If the 53 plane is also a plane of symmetry, then with

one obtains from Eq. (ii) and (x) that

so that no further reduction takes place. That is, the symmetry with respect to Si and 52 planes
automatically ensures the symmetry with respect to the 53 plane.

(c) All planes that are perpendicular to the £3 plane have their normals parallel to the plane
formed by e^ and 62- Let ej' denote the normal to the Sp plane which makes an angle of/? with
yt
the ej axis and —-J3 with the 62 axis, then with respect to the following set of prime basis:
£

the transformation law Eq. (ii) gives