## 2aPAb13. On the reflection of elastic waves in monoclinic incompressible materials.

### Session: Tuesday Morning, May 14

### Time: 11:45

**Author: Dimitrios A. Sotiropoulos**

**Author: Sudhakar Nair**

**Location: Dept. of Mech., Mater., and Aerospace Eng., Illinois Inst. of Technol., Chicago, IL 60616**

**Abstract:**

The reflection of plane elastic waves from a free surface of monoclinic
incompressible materials is examined under plane strain conditions in a plane of
material symmetry. The propagation condition is derived which together with the
law of reflection yields an inequality that defines the range of existence of
the two (one homogeneous and the other homogeneous or inhomogeneous) reflected
waves in terms of the angle of incidence of a homogeneous wave, the orientation
of the free-surface with respect to a material axis of symmetry, and the elastic
constants of the monoclinic material. The critical orientation beyond which
there exist two homogeneous reflected waves is derived in explicit form in terms
of the elastic constants. One of these reflected waves has an angle of
reflection equal to the angle of incidence only for specific orientations which
are found. In the range of existence of the two reflected waves, exclusion
points are defined for which there exists only one reflected (homogeneous) wave
with nonzero amplitude.

from ASA 131st Meeting, Indianapolis, May 1996