Sound attenuation apparatus and methods

Abstract

A method for manufacturing a sound attenuation apparatus includes generating a three-dimensional digital model of the sound attenuation apparatus and manufacturing the sound attenuation apparatus based on the model using an additive manufacturing technique. The model includes a body with an interior extending between a bottom surface and a top surface; and a stacked cavity structure having a structure inlet; a passage extending from the structure inlet into the interior to a base surface within the interior of the body; a support spine formed within the interior; and a plurality of arms extending from the support spine and at least partially forming a plurality of overlapping cavities with cavity inlets fluidly coupled to the passage. Each of the plurality of arms include a proximal first arm segment extending from the support spine and a first distal arm segment oriented at an angle relative to the proximal first arm segment.

What is claimed is: 
     
         1 . A method for manufacturing a sound attenuation apparatus, the method comprising:
 generating a three-dimensional digital model of the sound attenuation apparatus, the model comprising:
 a body with an interior extending between a bottom surface and a top surface; and 
 a stacked cavity structure comprising a structure inlet formed in the top surface of the body; a passage extending from the structure inlet into the interior of the body to a base surface within the interior of the body; a support spine formed within the interior of the body with a longitudinal axis defining a longitudinal orientation; and a plurality of arms extending from the support spine and at least partially forming a plurality of overlapping cavities relative to the longitudinal orientation with cavity inlets fluidly coupled to the passage, wherein each of the plurality of arms include a proximal first arm segment extending from the support spine and a first distal arm segment oriented at an angle relative to the proximal first arm segment; and 
   manufacturing the sound attenuation apparatus based on the model using an additive manufacturing technique.   
     
     
         2 . The method of  claim 1 , wherein the additive manufacturing technique is selected from the group consisting of: selective laser sintering; laser wire deposition;
 electron beam melting; laser engineered net shaping; and selective laser melting.   
     
     
         3 . The method of  claim 1 , further comprising applying a finishing treatment to the sound attenuation apparatus. 
     
     
         4 . The method of  claim 3 , wherein the applying the finishing treatment further comprises at least one of:
 polishing the sound attenuation apparatus;   applying a coating to the sound attenuation apparatus; and   machining the sound attenuation apparatus to final specifications.   
     
     
         5 . The method of  claim 1 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including at least three overlapping cavities. 
     
     
         6 . A method for manufacturing a sound attenuation apparatus, the method comprising:
 generating a three-dimensional digital model of the sound attenuation apparatus, the model comprising:
 a body with an interior extending between a bottom surface facing the mounting structure and a top surface; and 
 a stacked cavity structure comprising
 a structure inlet formed in the top surface of the body; 
 a passage extending from the structure inlet into the interior of the body to a base surface within the interior of the body; 
 a first cavity with a first cavity inlet fluidly coupled to the passage and being formed by a first arm, a first side wall within the interior of the body with a first side wall longitudinal axis, and the base surface, wherein the first arm extends from the first side wall and includes at least two first arm segments oriented at different angles relative to the first side wall longitudinal axis; and 
 
 a second cavity with a second cavity inlet fluidly coupled to the passage and being formed by a second arm, the first side wall, and the first arm, wherein the second arm extends from the first side wall and includes at least two second arm segments oriented at different angles relative to the first side wall longitudinal axis; and 
   manufacturing the sound attenuation apparatus based on the model using an additive manufacturing technique.   
     
     
         7 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the stacked cavity structure that includes
 a third cavity with a third cavity inlet fluidly coupled to the passage and being formed by a third arm, a second side wall within the interior of the body with a second side wall longitudinal axis, and the base surface, wherein the third arm extends from the second side wall and includes at least two third arm segments oriented at different angles relative to the second side wall longitudinal axis; and   a fourth cavity with a fourth cavity inlet fluidly coupled to the passage and being formed by a fourth arm, the second side wall, and the third arm, wherein the fourth arm extends from the second side wall and includes at least two fourth arm segments oriented at different angles relative to the second side wall longitudinal axis.   
     
     
         8 . The method of  claim 7 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the first and second cavity inlets on an opposite side of the passage relative to the third and fourth cavity inlets. 
     
     
         9 . The method of  claim 8 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the second wall as a support spine with a longitudinal axis, and wherein the first, second, third, and fourth cavities extend about the longitudinal axis. 
     
     
         10 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including
 the at least two first arm segments of the first arm including a proximal first arm segment with a first end positioned on the first side wall and extending away from the first side wall to a second end and a distal first arm segment with a first end positioned on the second end of the proximal first arm segment and extending away from the proximal first arm segment to a second end, and   the at least two second arm segments of the second arm including a proximal second arm segment with a first end positioned on the first side wall and extending away from the first side wall to a second end and a distal second arm segment with a first end positioned on the second end of the proximal second arm segment and extending away from the proximal second arm segment to a second end.   
     
     
         11 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the at least two first arm segments of the first arm include a proximal first arm segment with a first end positioned on the first side wall and extending away from the first side wall to a second end, at least one intermediate first arm segment with a first end positioned on the second end of the proximal first arm segment and extending away from the proximal first arm segment to a second end, and a distal first arm segment with a first end positioned on the second end of the at least one intermediate first arm segment and extending away from the at least one intermediate first arm segment to a second end. 
     
     
         12 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the at least two first arm segments of the first arm having a proximal first arm segment extending from the first side wall at a first interior angle of less than 90°. 
     
     
         13 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the first cavity defining a first volume and the second cavity defining a second volume, different from the first volume. 
     
     
         14 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the first cavity having a first height proximate to the first side wall that is greater than a second height at the first cavity inlet. 
     
     
         15 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the stacked cavity structure having a third cavity with a third cavity inlet fluidly coupled to the passage and being formed by a third arm, the first side wall, and the second arm, wherein the third arm extends from the first side wall and includes at least two third arm segments oriented at different angles relative to the first side wall longitudinal axis. 
     
     
         16 . The method of  claim 15 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the second cavity inlet defining a second cavity inlet length and the third cavity inlet defining a third cavity inlet length, different than the second cavity inlet length. 
     
     
         17 . The method of  claim 6 , wherein the generating the three-dimensional digital model of the sound attenuation apparatus further comprises the model including the stacked cavity structure having a hexagonal cross-sectional shape. 
     
     
         18 . The method of  claim 6 , wherein the additive manufacturing technique is selected from the group consisting of: selective laser sintering; laser wire deposition; electron beam melting; laser engineered net shaping; and selective laser melting. 
     
     
         19 . The method of  claim 6 , further comprising applying a finishing treatment to the sound attenuation apparatus.