ON THE NUMBER OF DISTINCT ELASTIC-CONSTANTS ASSOCIATED WITH CERTAIN ANISOTROPIC ELASTIC SYMMETRIES

It is demonstrated that for the monoclinic, tetragonal and trigonal li near elastic anisotropic symmetries the number of independent elastic constants (independent components of the elasticity tenser) may be red uced by one by the appropriate selection of a reference coordinate sys tem. For monoclinic symmetry this is a reduction from 13 to 12 distinc t constants and for the tetragonal (7 constant) and trigonal (7 consta nt) symmetries it is a reduction to the tetragonal (6 constant) and tr igonal (6 constant) symmetries. This algebra is accomplished using a f ormulation in which the elasticity tenser is a second rank tenser in a space of six dimensions, rather than a fourth rank tenser in a space of three dimensions as is customarily the case.