Patent ID: 11867087
Assignee: ROLLS-ROYCE PLC
Field: Measurement (Instruments)
Classification: CPC F  G | IPC B  F  G

Claim 0:
1. A composite fan blade root comprising:
an outer region comprising composite material and defining an outer inspection surface of the fan blade root; and
an internal reflection boundary embedded within the fan blade root, the internal reflection boundary being configured to change a velocity of a signal emitted into the fan blade root from the outer inspection surface;
the fan blade root further comprises an inner region surrounded by the outer region, wherein the internal reflection boundary is in the form of a discontinuous layer of boundary material which delimits the inner region from the outer region and which has different acoustic properties from, and is embedded within, the composite material of the outer region;
wherein the internal reflection boundary is defined by a plurality of discrete portions of the boundary material.