Measured Damping of Shuttle Acoustic Test Structures,

Damping measurements have been made on ten shuttle structural test specimens which were constructed for acoustic testing. These specimens include the cargo bay doors, the OMSRCS pod, the wing leading edge section, the wing elevon section, the body flap, the tail section, three fuselage panels and one wing panel. The damping of each natural mode of vibration for each specimen is plotted versus the natural frequency. Statistical analysis, including the mean, standard deviation and probability density for the damping data is presented. The analysis demonstrates that the damping ratio decreases with increasing frequency and that the logarithm of the damping ratio has a normal distribution. Author