Abstract: A method of manufacturing a component comprising a hollow axisymmetric body formed of a cured composite material is provided. The method includes the step of positioning the constituents of the composite material in a mold corresponding to at least a portion of the hollow axisymmetric body. The composite material is cured into a composite part, and residual stresses are generated in the composite material during the curing by controlling the temperature of the constituents in the mold. When the composite part is released from the mold, relaxation of the residual stresses causes one or more regions of the composite part to deflect in the radial direction of the hollow axisymmetric body, the position of greatest radial deflection of each region having a radial deflection which is at least 0.1% of the greatest diameter of the hollow axisymmetric body.

Abstract: Apparatus 200 for forming a composite component is disclosed, the apparatus comprising: a deformable mold tool 204 that at least partially defines a mold cavity 212; an interface layer 222 formed on an external surface of the mold tool 204; and at least two peristaltic actuators 206, mounted to contact the interface layer 222 and to generate a peristaltic pressure wave in the mold tool 204. The peristaltic actuators comprise rollers 206, pistons 306 or bi-metallic blocks 406. A method of forming a composite component is also disclosed, the method employing a mold tool 204 that at least partially defines a mold cavity 212. The method comprises: placing reinforcing fibers into the mold cavity 212, forcing a matrix material into the mold cavity 212 through the reinforcing fibers, and generating a peristaltic pressure wave within the mold tool 204 during forcing of the matrix material into the mold cavity 212.

Abstract: A composite flange element formed on a casing comprising a portion of a component and an adjoining flange portion, the composite having a ply layup comprising: one or more first plies extending over both the portion of the component and the flange portion; one or more second plies extending over the flange portion; and one or more third plies extending over the portion of the component; wherein the first, second and third plies are selected to provide desirable properties for the portions over which they extend. The flange element so formed consists of one or more load spreading features associated with the flange portion and one or more stress reduction features in the region where the portion of the component meets the flange portion. Preferably the plies are arranged or interleaved such that they run up the case and flange without distortion.

Abstract: A method of conditioning a first, heterogeneous contact surface for operational engagement with a second contact surface, the method comprising: performing a smoothing operation on part or all of the first contact surface while subjecting said part or all of the first contact surface respectively to a contact pre-stress corresponding to a nominal operational contact stress between the first and second contact surfaces.

Abstract: A containment casing is provided comprising a radially outer layer; an intermediate energy absorbing layer, and a retention framework for retaining an aerofoil blade in the event of detachment of whole or part of the blade. The retention framework is distributed axially and circumferentially along the casing and extends substantially radially inwardly at least partially through the intermediate energy absorbing layer.

Abstract: A method is provided that enables the identification of a region of a layered composite component that a test signal has passed through. The method comprises applying a label to the test signal as it passes through the region, such that the label applied to the test signal is indicative of the said region. The labelled signal can be identified by a sensor, even if the signal is of low strength and amongst a lot of noise, such as that caused by the multiple reflections and refractions that take place when an acoustic signal passes through a layered composite component.

Abstract: A composite material and method for manufacturing the material, the material including: a plurality of plies layered one on top of the other; and one or more through-thickness fibers which join one or more of the plurality of plies to one another; wherein the one or more through-thickness fibers form a boundary which delineates one or more discrete regions of the material.

Abstract: A method for locating artifacts, such as particles or voids, in a material includes the steps of defining a path through a volume of the material, sensing the presence and type of any artifacts along the path and determining for each sensed artifact, the respective distance along the path. Analysis of the quantity of sensed artifacts and their respective position along the path enables the determination of measures for the artifact density, artifact size and artifact distribution in the material.

Abstract: Blades for gas turbine engines which are formed from composite materials have problems with respect of resistance to impacts such as bird strikes. Previous blades formed from metals had some ductility towards the trailing edge which could accommodate the whiplash effects of impacts. With regard to composite materials such ductility is not present. By providing projections 32 which act as propagation wave trips as well as high intensity reflectors 36 it is possible to limit the whiplash at the edge 31 resulting in damage. Typically a cladding cap 38 is provided which also may be formed from a metal to allow some greater uniformity with respect to mass per length despite the tapering of the blade. Furthermore by providing voids which act as delamination initiation sites cracking can be provided between plies which allows greater flexibility towards the edge and therefore release of energy. These voids may incorporate uncured polymer matrix to act as a binder subsequent to delamination.

Abstract: A fiber cutting device and method for cutting one or more exposed portions of a through-thickness fiber in a surface of a composite material, the device including: a cutting element for cutting the one or more exposed portions; a suction device which is operable to extract the cut exposed portions from the surface of the composite material; and a storage device for receiving the cut exposed portions.

Abstract: A mold for a composite component having a fillet joint, the mold including a mold body having a cavity within which the component is formed, and an insert mating with the mold body and including a forming surface against which, in use, the fillet of the component fillet joint is formed. The insert may be thermally insulating and highly rigid. A method of forming a composite component having a fillet joint using a mold, the method including forcing a surface of the fillet region of the component to adopt a non constant radius of curvature while the component is inside the mold during the cure process is also provided. Additionally, a method of forming a composite component having a fillet joint that is defined between first and second legs the method including placing the legs of the component in bending during cure of the component is described.

Abstract: A strain gauge assembly is disclosed, including a plurality of strain gauges arranged in a side-by-side relationship, each having a first end and a second end. The first and/or second end of one of the plurality of strain gauges is offset from a corresponding first and/or second end of another of the plurality of strain gauges.

Abstract: A composite material comprises plies 2, 4, 6, 8, which may be prepregs. Film elements 10 are provided between at least two adjacent ones of the plies 2, 4, 6, 8. The film elements are made from a release material which inhibits adhesion between regions of the resin on opposite sides of the respective film elements, and are randomly distributed. The film elements 10 provide delamination sites within the component. The component may be a test piece for assessing the delamination behavior of the material. Alternatively, the delamination behavior caused by the film elements 10 may have a useful purpose, for example to control regions of a component in which delamination occurs following events such as a bird strike on a fan blade of a gas turbine engine.

Abstract: Composite aerofoils for gas turbine engines are commonly provided with a metal protection strip along the leading edge, to prevent erosion of the leading edge in use and to protect against impacts from foreign bodies. A problem with such strips is that they can cause serious damage to other parts of the engine if they become detached from the aerofoil. The invention provides an aerofoil having such a protection strip, characterized in that the protection strip includes one or more weakening features to reduce the ability of the protection member to withstand a compressive force applied along its length. The weakening features encourage the protection member to break up under impact, or if it becomes detached from the aerofoil, so that damage to other parts of the engine is minimized.

Abstract: Aerofoils (22) of a gas turbine engine are provided with a coating (34) or filler (44) of viscoelastic material. As ice accretes on the aerofoils (22) during operation, the resulting aerodynamic stability imbalance induces vibration in the aerofoils (22). The viscoelastic material (34, 44) damps this vibration, and in so doing generates heat, which melts the ice away from the aerofoils (22). Heat-conducting members conduct the heat to regions of the component in which ice accretion is to be prevented. Alternative embodiments are described in which the pseudoelastic behavior of a shape memory alloy (56), or eddy currents arising from the rotor blades' rotation in an axisymmetric magnetic field, are used as sources of heat.

Abstract: A method for locating artefacts, such as particles or voids, in a material includes the steps of defining a path through a volume of the material, sensing the presence and type of any artefacts along the path and determining for each sensed artefact, the respective distance along the path. Analysis of the quantity of sensed artefacts and their respective position along the path enables the determination of measures for the artefact density, artefact size and artefact distribution in the material.

Abstract: A composite blade (26) comprises a three-dimensional arrangement of reinforcing fibers (58) and a matrix material (60) infiltrated around the three-dimensional arrangement of woven reinforcing fibers (60). The three-dimensional arrangement of woven reinforcing fibers (58) defines a plurality of cavities (56) within the aerofoil (28). The composite blade (26) comprises an aerofoil portion (38) and a root portion (36). The aerofoil portion (38) comprises a leading edge (44), a trailing edge (46), a concave pressure surface wall (50), a convex suction surface wall (52) and a tip (48). The aerofoil portion (36) comprises a plurality of webs (54) extending between, and being secured to, the concave pressure surface wall (50) and the convex suction surface wall (52) to produce a Warren girder structure. The three-dimensional arrangement of woven reinforcing fibers (58) are arranged to produce the concave pressure surface wall (50), the convex suction surface wall (52) and the plurality of webs (54).

Abstract: A system is provided for improving the damage tolerance of a rotor assembly. The system includes one or more measurement subsystems for measuring the stresses in respective parts of the rotor assembly and issuing respective measurement signals. The system also includes a control subsystem for receiving the measurement signals from the measurement subsystems, determining a response to measured stresses indicative of crack growth, and issuing response signals. The system also includes one or more release subsystems for receiving respective response signals, and activating controlled release of material from respective parts of the rotor assembly to mitigate the effect of the crack growth.

Abstract: A method of modifying excitation response characteristics of a structural system, including an aerofoil blade mounted to a support disc, including the steps: (a) identifying a limit cycle associated with the system; (b) determining the amplitude of the limit cycle; (c) comparing the amplitude of the limit cycle against a threshold value; and (d) if the amplitude of the limit cycle is greater than a threshold value, modifying the system to reduce the amplitude of the limit cycle.

Abstract: A method of conditioning a first, heterogeneous contact surface for operational engagement with a second contact surface, the method comprising: performing a smoothing operation on part or all of the first contact surface whilst subjecting said part or all of the first contact surface respectively to a contact pre-stress corresponding to a nominal operational contact stress between the first and second contact surfaces.