METHOD OF MAKING SOUND-ABSORBING STRUCTURE WITH DIFFERENT-HEIGHT AGGREGATE OF VARIOUS CONFIGURATIONS Russian patent published in 2024 - IPC B32B3/12 

FIELD: aircraft engineering.

SUBSTANCE: invention relates to aircraft engineering, specifically to a method for manufacturing a sound-absorbing structure (SAB) of a resonant type, intended for use in sound-absorbing panels of a turbojet engine and in transport equipment, including in the manufacture of flow paths of modern aircraft engines. Method of making a sound-absorbing structure includes laying an aggregate, the cells of which are made of different configuration and are divided into groups. In the cells of each group, located in a spiral around the central cell with the largest volume, different amounts of material are introduced to form cells with different heights with reduced volumes relative to the central cell, and around the central cell with the smallest volume there formed are cells with different heights with increased volumes relative to the central cell. Ratios of volumes surrounding the central cell are selected so that its acoustic efficiency is enhanced as compared to a single central cell. Material is introduced into aggregate cells starting from facing sheet. Material introduced into the aggregate cells is a rigid material which is placed at a different angle of inclination relative to the base of the cell, or a rigid material together with a permeable or elastic membrane or porous-fibrous material. Then, the obtained structure is cooled and cured, then the surfaces of the structure elements to be glued are cleaned and degreased, then glue is applied on both ends of aggregate, facing sheet is successively laid on one of end surfaces of aggregate. Permeable surface is laid on the other end surface of the aggregate. Obtained assembly is compressed and the glue is cured.

EFFECT: simplifying the method of making a sound-absorbing structure, which enables to increase efficiency of reducing noise generated by a gas or air flow.

1 cl, 4 dwg