High-Intensity Acoustic Tests of a Thermally Stressed Plate

An investigation was conducted in the Thermal Acoustic Fatigue Apparatus to study the random motion of a buckled aluminum plate exposed to heat and intense acoustic loads. Plate buckling was due to thermal stress. The plate was exposed to noise levels up to 160 dB and temperatures to 250°F. Two different thermal boundary conditions of the plate were studied; one condition with the plate clamped in a steel frame and the other with the plate insulated from the steel frame. For the second condition, the temperature distribution and buckling deflection were considerably different from the first condition. The acoustic response was also significantly different for the two boundary conditions. The general trends of the changes in resonant frequencies and random response of the plate agree with previous theoretical prediction and experimental results.