Bending, Ringing, Breaking and Flowing, Ch Elastic waves in a solid and at its surface
Problem
A plane P wave in a Poisson solid (ν=0.25, so cL/cT=3) strikes a stress-free plane surface at an angle of incidence θP=70∘ from the normal.
((a)) Find the angle θS of the reflected SV wave.
((b)) Using the free-surface reflection coefficient RPP=sin2θPsin2θS+(cL/cT)2cos22θSsin2θPsin2θS−(cL/cT)2cos22θS, obtained from the two traction-free boundary conditions, decide whether any energy returns as P, and state what fraction of the incident energy leaves as SV.