Sound propagation characteristics of various materials have been investigated. A methodology to evaluate and compare the acoustic responses of metallic and non-metallic materials was developed and validated. Various materials were acoustically examined under impact loading using a test set-up consisting of a solenoid-driven hammer, a microphone, and software to record, Fourier transform, and analyze the sound response. Materials studied for acoustic behavior included steel, cast and wrought aluminum, gray cast iron, titanium, and various composites. All materials were ranked based on their reduction of sound pressure compared to a reference material of hardened tool steel. Test data were normalized on an A-weighted scale to account for the enhanced sensitivity of the human ear at certain frequencies. The effects of specimen geometry and material composition on the resulting sounds were also incorporated in the investigation. A complete microstructural analysis was conducted on each material to relate its acoustic behavior to intrinsic material characteristics. The experimental and analytic tools and knowledge developed in this study were further applied in a manufacturing setting to redesign an impact stop for noise reduction. The proposed prototypes were tested in the industrial environment, and the results compared to the findings from the study. These developments will be systematically presented and discussed.

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