초록 ▼

The invention relates to the field of needling processes for forming fibrous preform structures. The invention is particularly useful in forming fibrous preform structures suitable for subsequent processing into high temperature resistant composite structures such as carbon/carbon aircraft brake dis

The invention relates to the field of needling processes for forming fibrous preform structures. The invention is particularly useful in forming fibrous preform structures suitable for subsequent processing into high temperature resistant composite structures such as carbon/carbon aircraft brake disks. The process according to the invention compensates for fiber pull back induced by fiber resilience, and for compaction in previously needled layers induced during subsequent needling passes. According to a further aspect of the invention, Z-fiber distribution throughout the thickness of the fibrous preform structure may be manipulated as necessary to achieve a desired distribution.

대표청구항 ▼

A process for forming a fibrous preform structure, comprising the steps of: disposing a fibrous structure comprising at least two superposed fibrous layers beneath a multitude of felting needles, one of said layers being a top layer that defines an exposed surface, wherein fiber is to be transported

A process for forming a fibrous preform structure, comprising the steps of: disposing a fibrous structure comprising at least two superposed fibrous layers beneath a multitude of felting needles, one of said layers being a top layer that defines an exposed surface, wherein fiber is to be transported within said fibrous structure during a needling pass in which said fibrous structure is passed beneath a multitude of felting needles while said multitude of felting needles are repeatedly driven into said fibrous structure through said exposed surface, said fiber having a tendency to pull back to a layer from which that fiber originates unless transported a minimum distance from that layer; determining a fiber transport depth relative to said top layer to transport fiber at least said minimum distance from each layer in a chosen set of layers and wherein any fiber transported from fibrous layers disposed beneath said chosen set of layers is transported less than said minimum distance, said chosen set of layers including at least said top layer; and, transporting fiber to said desired fiber transport depth by subjecting said fibrous structure to said needling pass.