Method for creating alveolar cores having open inner conical shapes
A method for manufacturing a sound attenuating panel uses an alveolar-core structure including a first edge and a second edge separated by alveolar cells, the alveolar cells including walls extending from the first and second edges and defining a primary conduit for the circulation of a sound wave that is to be attenuated. The method includes covering the first edge or the second edge of the alveolar-core structure with a compartmentation wall; deforming the compartmentation wall to define at least one secondary conduit for the circulation of a sound wave that is to be attenuated, the secondary conduit extending at least partially within said primary conduit; and creating an opening in the compartmentation wall to permit communication between the primary and secondary conduits.
1. A manufacturing method for manufacturing an alveolar core structure for an acoustic attenuation panel, the alveolar core structure comprising a first edge and a second edge separated by a plurality of alveolar cells, each of the plurality of alveolar cells comprising a plurality of walls extending between the first edge and the second edge and defining a primary duct for circulating a sound wave to be attenuated, wherein the manufacturing method comprises:
at least partially covering the first edge of the alveolar core structure with a compartmentalization wall such that the compartmentalization wall covers at least two of the primary ducts;
deforming the compartmentalization wall from the first edge so as to form at least two secondary ducts extending from the first edge in the at least two of the primary ducts, the compartmentalization wall remaining as a single piece after the deforming, and the at least two secondary ducts are empty; and
forming openings within the compartmentalization wall so as to enable communication between each secondary duct and a respective one of the at least two of the primary ducts.
2. The manufacturing method according to claim 1 , wherein the compartmentalization wall includes a deformable and expandable film, and wherein the manufacturing method further comprises, subsequent to deforming the compartmentalization wall, consolidating the compartmentalization wall in its deformed position.
3. The manufacturing method according to claim 2 , wherein the deformable and expandable film of the compartmentalization wall is reinforced by a deformable and expandable textile structure.
4. The manufacturing method according to claim 1 , wherein the openings are formed in the compartmentalization wall before the deforming the compartmentalization wall.
5. The manufacturing method according to claim 1 , wherein the openings are formed in the compartmentalization wall after the deforming the compartmentalization wall.
6. The manufacturing method according to claim 1 , wherein the openings are formed in the compartmentalization wall simultaneously with the deforming the compartmentalization wall.
7. The manufacturing method according to claim 1 , wherein the deforming of the compartmentalization wall is obtained by mechanical deformation of the compartmentalization wall by a mechanical deformation device comprising at least one deformation member configured to exert one of a pressure and a tension on one face of the compartmentalization wall.
8. The manufacturing method according to claim 7 , wherein the openings are formed in the compartmentalization wall simultaneously with the deforming the compartmentalization wall and the openings are formed by a punch mounted on the at least one deformation member of the mechanical deformation device.
9. The manufacturing method according to claim 1 , wherein the deforming the compartmentalization wall is obtained by applying a differential pressure on either side of the compartmentalization wall.
10. The manufacturing method according to claim 1 , wherein the compartmentalization wall has one of an ogive-like, a conical, and a frustoconical shape in its deformed position.
11. The manufacturing method according to claim 1 , wherein the at least two secondary ducts each comprise a first end disposed inside a respective one of the at least two of the primary ducts and a second end opposite the first end, the openings are formed proximate the first end and the second end is open.