Self-muffling acoustic duct assembly for noise attenuation in a vehicle and method of using the same

An aircraft comprising:

• an environmental control system comprising:
• an air conditioning unit;
• and
• one or more self-muffling acoustic duct assemblies, each self-muffling acoustic duct assembly comprising:
• a duct having a tube shape, the duct comprising:
• two or more reinforced thermoplastic composite laminate layers forming a duct structure of the duct, the two or more reinforced thermoplastic composite laminate layers having a plurality of openings for noise to travel through the duct;
• and
• a thermoplastic film sealing layer embedded between the two or more reinforced thermoplastic composite laminate layers, the thermoplastic film sealing layer forming a barrier to prevent leakage of air from the duct and being transparent to the noise traveling through the duct;
• an insulation and noise attenuating layer coupled to, and covering, the duct structure;
• and
• a thermoplastic film outer layer coupled to the insulation and noise attenuating layer,
• wherein each self-muffling acoustic duct assembly provides noise attenuation in a cabin of the aircraft, and further wherein the duct allows transmission of the noise through the duct and into the insulation and noise attenuating layer where the noise is attenuated, while avoiding delamination of the thermoplastic film sealing layer in the duct, and while avoiding use of one or more separate zone mufflers in the duct.

A method of using one or more self-muffling acoustic duct assemblies to attenuate noise in a vehicle, the method comprising steps of:

• forming the one or more self-muffling acoustic duct assemblies, each of the one or more self-muffling acoustic duct assemblies comprising:
• a duct having a tube shape, the duct comprising:
• two or more reinforced thermoplastic composite laminate layers forming a duct structure of the duct, the two or more reinforced thermoplastic composite laminate layers having a plurality of openings for the noise to travel through the duct;
• and
• a thermoplastic film sealing layer embedded between the two or more reinforced thermoplastic composite laminate layers, the thermoplastic film sealing layer forming a barrier to prevent leakage of air from the duct and being transparent to the noise traveling through the duct;
• an insulation and noise attenuating layer coupled to, and covering, of the duct structure;
• and
• a thermoplastic film outer layer coupled to the insulation and noise attenuating layer;
• coupling the one or more self-muffling acoustic duct assemblies to an environmental control system in the vehicle;
• and
• using the one or more self-muffling acoustic duct assemblies to attenuate the noise in a passenger area of the vehicle, by allowing transmission of the noise through the duct and into the insulation and noise attenuating layer, while avoiding delamination of the thermoplastic film sealing layer in the duct, and while avoiding use of one or more separate zone mufflers in the duct.