ASA 127th Meeting M.I.T. 1994 June 6-10

4pSAb6. Beam vibration studies using measured bending wave impedance.

S. K. Kim

M. G. Prasad

Noise and Vib. Control Lab., Dept. of Mech. Eng., Stevens Inst. of Technol., Hoboken, NJ 07030

Acoustic impedance in a plane-wave field is obtained experimentally using the well-known two-sensor technique. Recently, in the literature, the application of this technique to determine bending wave impedance has been demonstrated. In transverse vibration, the impedance is defined in terms of force and moment and the corresponding linear and angular velocities, respectively. The determination of bending wave impedance is based on the reflection coefficient which is obtained from the measured transfer function. Thus impedance evaluated using the measured transfer function and reflection coefficient is useful in characterizing the effects of boundary conditions, discontinuities, etc., in vibrating structures. In this study, bending wave impedance in a transversely vibrating cantilever beam is determined using the two-sensor technique. In addition to impedance, the measured transfer function and reflection coefficient are also used to describe the characteristics of a fixed end and a joint. The applications of impedance characterization to vibration analysis of connected structures are discussed. [Work supported by Daewoo Motor Company, Seoul, Korea.]