“…This paper reports experimentally registered polar scans which are compared with numerically computed polar scans for a variety of composite materials, using both pulsed and harmonic ultrasonic beams. Typically, dark rings are observed in a polar plot, which are linked to the generation of critical bulk waves (pulsed regime) or to the generation of guided waves (harmonic regime) (Declercq et al, 2006a, Declercq et al, 2006b, Degrieck et al, 2003. Both types of waves are vigorously entangled with the elastic constants of the material (Rose, 1999, Nayfeh and Chimenti, 1988, Auld, 1990).…”