FOCUSING OF ACOUSTIC MODES IN THIN ANISOTROPIC PLATES

Focusing of acoustic energy radiated from a point-like source in a thi n anisotropic plate is studied theoretically. Caustics are shown to oc cur in the focusing patterns of both flexural and slow horizontally po larized modes but do not exist for the fast horizontally polarized mod e. Elastic constant ratios supporting caustic existence in (001) plate s of materials with cubic symmetry are determined. Calculations on foc using of all three thin plate modes for silicon, lithium and paratellu rite with (001) plate orientation as well as for a unidirectional fibe r-reinforced composite material are presented.