## Acoustic axes in triclinic anisotropy

**Vaclav Vavrycuk**
### Summary

Calculation of acoustic axes in triclinic elastic anisotropy is considerably
more complicated than for anisotropy of higher symmetry. While one polynomial
equation of the 6th order is solved in monoclinic anisotropy, we have to solve
two coupled polynomial equations of the 6th order in two variables in triclinic
anisotropy. Furthermore, some solutions of the equations are spurious and must
be discarded. In this way we obtain 16 isolated acoustic axes, which can run
in real or complex directions. The real/complex acoustic axes describe
the propagation of homogeneous/inhomogeneous plane waves and are associated with
a linear/elliptical polarization of waves in their vicinity. The most frequent
number of real acoustic axes is 8 for strong triclinic anisotropy and 4 to
6 for weak triclinic anisotropy. Examples of anisotropy with no or 16 real
acoustic axes are presented.

### Whole paper

The reprint is available in
PDF (284 kB).

*J. Acoust. Soc. Am.*, **118** (2005), 647-653.

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