Computation of Propagation Speed and Reflection of Axially Symmetric Waves in Composite Cylinders, with Application to Impedance Tube and Calibrator.
NAVAL RESEARCH LAB WASHINGTON DC
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Waveguide theory is applied to the interpretation of data on reflection and propagation of sound in a water-filled impedance tube and in an acoustic calibrator. Computer programs are described and documented that relate propagation speed and attenuation for the sample in the impedance tube to the complex reflection coefficient relate propagation speed in the sample in the impedance tube to the elastic moduli of the sample material, both real and complex and compute the propagation speed in the acoustic calibrator. A correction factor is developed to account for the lack of rigidity of the reflector in the impedance tube. The major conclusion with respect to the data reduction for the impedance tube is the observation that the relevant wave speed is not necessarily the dilatational wave speed, but is a function of the space between sample and tube wall. By modifying the experimental arrangement one may measure two separate elastic moduli. Author
- Laminates and Composite Materials