Sound proof helmet

摘要

Novel methods and systems for acoustic proofing are disclosed. A sound proof helmet can be designed by optimizing several layers of different materials, thickness, and physical properties. The thickness of the layers can be smaller than the wavelength of the sound waves which are meant to be reduced.

主权项

1. A sound proof helmet comprising:
a plurality of homogeneous layers arranged in a concentric hemispherical sequence, each homogeneous layer of the plurality of homogeneous layers having a thickness smaller than a wavelength in a desired acoustic frequency range, the plurality of homogeneous layers arranged in a sequence configured to optimize acoustic proofing, the plurality of homogeneous layers comprising
at least one first homogeneous layer of a first material with a low bulk modulus; andat least one second homogeneous layer of a second material with a high bulk modulus.