FIELD

This application relates to porous composite structures and, more particularly, to a tooling assembly, system and method for manufacturing porous composite structures.

BACKGROUND

Acoustically treated composite structures reduce sound by scattering or absorbing sound energy. Due to this sound attenuating capability, acoustically treated composite structures have been used in various industries, including the aerospace industry. For example, acoustically treated composite structures are commonly incorporated into bypass gas turbine aircraft engines, such as into the inlet inner barrels, fan duct walls and/or exhaust nozzles, to attenuate the noise associated with high volume airflows.

Conventional acoustically treated composite structures include sandwich structures having a septumized honeycomb core, a perforated facesheet and an impermeable facesheet. The perforations defined by the perforated facesheet fluidly couple the cavities of the septumized honeycomb core with the ambient environment. Therefore, when air flows across the perforated facesheet, the cavities in the core act as Helmholtz resonators and attenuate the sound of the associated airflow. More specifically, core walls between adjacent cavities in the core act as acoustic septa to attenuate the sound of the airflow.

Septumized honeycomb cores, however, are expensive and processes for bonding facesheets to the cores can require multiple cure cycles. Further, current processes for perforating composite structures are typically time-intensive and are associated with high material costs. For example, abrasive perforation can have a significant cycle time, have complex tooling, and/or require a considerable amount of cleanup. Mechanical drilling can have a significant cycle time, have a recurring cost of drill bit replacements, and/or result in the cutting of fibers (which diminishes the strength of the facesheet). Drilling cycle time can be extensive for large acoustic panels with millions of perforations. Plastic pin mats can also be used to create perforations, but they are non-reusable and are thus formed to contour and trimmed to size for one-time usage.

Accordingly, those skilled in the art continue with research and development in the field of acoustically treated composite structures.

SUMMARY

Disclosed is a tooling assembly for manufacturing a porous composite structure. The tooling assembly includes a first tooling member and a second tooling member configured to hold a green layup, a fluid movement device configured to move fluid through the layup, and a manifold system configured to distribute the fluid as the fluid moves through the layup.

Also disclosed is a tooling assembly that includes a first tooling member and a second tooling member. The first tooling member includes a first body that defines a first internal volume and a first inlet. The first inlet is fluidly coupled with the first internal volume. The first tooling member also includes a first tooling surface that defines a plurality of first perforations that are fluidly coupled with the first internal volume. The second tooling member includes a second body that defines a second internal volume and a second inlet. The second inlet is fluidly coupled with the second internal volume. The second tooling member also includes a second tooling surface that defines a plurality of second perforations that are fluidly coupled with the second internal volume.

Also disclosed is a system for manufacturing a porous composite structure. The system includes a tooling assembly having a first tooling member and a second tooling member. The first tooling member includes a first body that defines a first internal volume and a first inlet. The first inlet is fluidly coupled with the first internal volume. The first tooling member also includes a first tooling surface that defines a plurality of first perforations that are fluidly coupled with the first internal volume. The second tooling member includes a second body that defines a second internal volume and a second inlet. The second inlet is fluidly coupled with the second internal volume. The second tooling member also includes a second tooling surface that defines a plurality of second perforations that are fluidly coupled with the second internal volume. The system further includes a layup positioned between the first tooling surface of the first tooling member and the second tooling surface of the second tooling member.

Also disclosed is a method for manufacturing a porous composite structure.

In one example, the disclosed method includes positioning a green layup between a first tooling surface and a second tooling surface, wherein the first tooling surface includes a plurality of first perforations and the second tooling surface includes a plurality of second perforations, and establishing a flow of fluid through the plurality of first perforations, through the layup, and through the plurality of second perforations.

In another example, the disclosed method includes positioning a layup between the first tooling surface of the first tooling member of a tooling assembly and the second tooling surface of the second tooling member of the same tooling assembly. The first tooling member includes a first body that defines a first internal volume and a first inlet. The first inlet is fluidly coupled with the first internal volume. The first tooling member also includes a first tooling surface that defines a plurality of first perforations that are fluidly coupled with the first internal volume. The second tooling member includes a second body that defines a second internal volume and a second inlet. The second inlet is fluidly coupled with the second internal volume. The second tooling member also includes a second tooling surface that defines a plurality of second perforations that are fluidly coupled with the second internal volume. The method further includes establishing a flow of fluid from the first tooling member into the second tooling member wherein the fluid flows through the first perforations, through the layup and through the second perforations.

Also disclosed is a method for forming a plurality of tortuous paths in a green layup that includes a plurality of plies, each ply of the plurality of plies including reinforcing fibers embedded in a resin matrix, the method including (1) supporting the layup and (2) while the layup is supported, flowing fluid through the layup to displace at least some of the resin matrix, thereby forming said plurality of tortuous paths in the layup.

Various examples of the disclosed tooling assembly, system, method for manufacturing a porous composite structure, and method for forming a plurality of tortuous paths in a green layup will become apparent from the following detailed description, the accompanying drawings and the appended claims.

