Designing Quiet Structures Using Optimally Tuned Absorbers

This grant provides funding for research toward a design methodology to quiet noisy machines. The methodology will apply to machines with both thick, such as castings, and thin, such as stampings, casings. The strategy adopted for thick casings will be to enclose the thick casing with a thin-shell enclosure incorporating tuned vibration absorbers to reduce radiated noise. Composite and metal enclosures will be studied. The strategy for thin casings will include the addition of tuned absorbers directly attached to the structure to allow passive noise control over a wide frequency band. Numerical techniques will be employed, including finite element analysis, acoustics and optimization. Research will also focus on the development of efficient dynamic analysis with tuned absorbers and on optimization for dynamic systems with absorber locations and parameters as variables. Consideration will be given to manufacturability. If successful, this research will lead to techniques for the design of more quiet appliances, automobiles and machines, including power transformers, factory floor machines, and a wide variety of household appliances. Noise reduction is a factor in product competition, and greater emphasis is being placed on noise emission from such devices.