| The basis for this thesis is the use of thin aluminum and aluminum clad materials in aircraft skin subjected to high intensity noise levels. The noise levels capable of inducing non-linear vibration response can be attributed to rotors, engines, and firing of weapon systems. The skin, typically being on the order of .032 to .063 of an inch thick, is riveted and bonded which represents a clamped plate condition. Using a loud speaker emitting a sinusoidal pseudo plane wave input to a fixtured clamped plate or panel, experimental results indicate that decreasing panel thickness results in lower fundamental frequencies. In addition, the effect of increased thickness is to shift the nonlinear response to higher excitation levels. Results showed that for plates of the same thickness, bare aluminum 2024-T3 achieved a higher nonlinear response level versus the aluminum clad 2024-T3 at similar dB levels for the same mode. |
