END RESONANCE IN INFINITE IMMERSED RODS OF DIFFERENT CROSS-SECTIONS

The edge resonance was discovered by E. A. G. Shaw [J. Acoust. Soc. Am . 28, 38-50 (1956)]. Since that time, many theoretical investigations justified this unusual behavior observed at the end of a free semi-inf inite plate by the superposition of the incident and three reflected w aves. In the present study, a spectrum analysis technique is used to i nvestigate the frequency response of a short acoustic pulse, normally incident on the end of infinite loaded steel rods of circular and nonc ircular (square, hexagonal, and rectangular) cross sections. For such samples, the experimental data confirm the existence of end resonances . The results give rise to a resonance frequency dependence with the c ross-sectional area which does not depend on the shape of the cross se ction but only on the value of the area. Particular attention is devot ed to the rectangular-section rod, intermediate sample between the one -dimensional problem (semi-infinite plate) and the two-dimensional pro blem (square rod). (C) 1996 Acoustical Society of America.