Abstract: The fan duct of a ducted fan gas turbine engine has a fan case lined with a honeycomb structure that acts to absorb the energy of a separated part of a blade. A layer of composite material lining honeycomb structure delaminates/breaks when a separated blade part passes through a further, inner honeycomb liner and hits it. The resulting free end of composite liner wraps round the striking end of the blade part, thus blunting the cutting action of the blade part and spreading the generated forces to the extent that the blade part is de-energised sufficiently to prevent it penetrating the fan case.

Abstract: The fan duct of a ducted fan gas turbine engine has a fan case (20) lined with a honeycomb structure (22) that acts to absorb the energy of a separated part of a blade (16). A layer of composite material (24) lining honeycomb structure (22) delaminates/breaks when a separated blade part passes through a further, inner honeycomb liner (26) and hits it. The resulting free end of composite liner (24) wraps round the striking end of the blade part, thus blunting the cutting action of the blade part and spreading the generated forces to the extent that the blade part is de-energised sufficiently to prevent it penetrating the fan case (20).

Abstract: The fan duct of a ducted fan gas turbine engine has a fan case lined with a honeycomb structure that acts to absorb the energy of a separated part of a blade. A layer of composite material lining honeycomb structure delaminates/breaks when a separated blade part passes through a further, inner honeycomb liner and hits it. The resulting free end of composite liner wraps round the striking end of the blade part, thus blunting the cutting action of the blade part and spreading the generated forces to the extent that the blade part is de-energised sufficiently to prevent it penetrating the fan case.

Abstract: A method of manufacturing an article (10) from two metal workpieces (30,32), the first and second metal workpieces (30,32) define the outer profile of the article (10). The second workpiece (32) is thicker than the first workpiece (30). The first workpiece (30) has two flat surfaces (34,36) and the second workpiece has one flat surface (38) and one machined (42) surface (40). Stop of is applied to surface (34) to prevent diffusion bonding at preselected areas. The workpieces (30,32) are assembled into a stack (58) so that the flat surfaces (34,38) are in abutment. Heat and pressure are applied to diffusion bond the workpieces (30,32) together to form an integral structure (60). The integral structure (60) is placed in a die such that the first workpiece (30) faces a convex surface of the die. The integral structure (60) is heated to cause the integral structure (60) to be hot creep formed on the convex surface of the die.