Abstract: A method of pre-stressing a component comprises providing an electrically conducting sheet adjacent to a component within a medium. An electrical discharge is supplied from an electrical discharge circuit to the electrically conducting sheet to produce vaporization of the electrically conducting sheet. The vaporization of the electrically conducting sheet produces a planar pressure pulse in the medium adjacent to the component. The planar pressure pulse impacts on a surface of the component to produce a region of residual compressive stress within the component.

Abstract: A composite article includes a composite member, a flexible member and at least one shape memory material member. The composite member has longitudinally extending fibers in a matrix material. The at least one shape memory material member extends substantially parallel to the composite member and the flexible member is positioned between the composite member and the at least one shape memory material member to bond the at least one shape memory material member to the composite member. The composite article is particularly suitable for use as a tab for an exhaust nozzle of a turbofan gas turbine engine.

Abstract: A gas turbine engine variable area exhaust nozzle has a plurality of first and second movable members arranged circumferentially around a fan casing extending in downstream. The first and second movable members alternate around the variable area nozzle. During cruise conditions the first and second movable members are in un-actuated positions. At take off conditions the first movable members are in an actuated position and the second movable members are in the un-actuated position. At top of climb conditions the first movable members are in the un-actuated position and the second movable members are in an actuated position. The first movable members move radially outwardly from the un-actuated position to the actuated position and the second movable members move radially inwardly from the un-actuated position to the actuated position.

Abstract: A method of pre-stressing a component such as a turbine blade (52) comprises providing an electrically conducting sheet (66) adjacent to a component (52) within a fluid medium (56). An electrical discharge is supplied from an electrical discharge circuit (58) to the electrically conducting sheet (66) to produce vaporisation there of (66). The vaporisation of the electrically conducting sheet (66) produces a planar pressure pulse in the medium (56) adjacent to the component (52). The planar pressure pulse impacts on a surface of the component (52) to produce a region of residual compressive stress within the component (52).

Abstract: An apparatus for determining a clearance between rotor blade tips of rotor blades mounted on a rotor and a stator lining mounted on a stator casing. The stator lining is movable radially relative to the stator casing. The stator lining comprises an abradable material. At least one probe is arranged to measure the clearance between blade tips and stator lining. A first portion of the at least one probe is arranged within the stator lining and a tip of the first portion of the at least one probe is arranged flush with the surface of the abradable material. The tip of the first portion of the at least one probe comprises an abradable material. A second portion of the at least one probe is secured to the stator casing. A wire-less and connector-less coupling transmits a measurement signal from the first portion to the second portion of the at least one probe to allow radial movement of the stator lining relative to the stator casing.

Abstract: A composite article includes a composite member, a flexible member and at least one shape memory material member. The composite member has longitudinally extending fibres in a matrix material. The at least one shape memory material member extends substantially parallel to the composite member and the flexible member is positioned between the composite member and the at least one shape memory material member to bond the at least one shape memory material member to the composite member. The composite article is particularly suitable for use as a tab for an exhaust nozzle of a turbofan gas turbine engine.

Abstract: An apparatus for determining a clearance between rotor blade tips of rotor blades mounted on a rotor and a stator lining mounted on a stator casing. The stator lining is movable radially relative to the stator casing. The stator lining comprises an abradable material. At least one probe is arranged to measure the clearance between blade tips and stator lining. A first portion of the at least one probe is arranged within the stator lining and a tip of the first portion of the at least one probe is arranged flush with the surface of the abradable material. The tip of the first portion of the at least one probe comprises an abradable material. A second portion of the at least one probe is secured to the stator casing. A wire-less and connector-less coupling transmits a measurement signal from the first portion to the second portion of the at least one probe to allow radial movement of the stator lining relative to the stator casing.

Abstract: In a turbofan gas turbine engine, a fan shaft is rotatably mounted and radially supported by a bearing in a bearing support structure supported from a fixed engine structure by radially frangible bolts and radially extending spokes. The radially inner ends of the radially extending spokes are mounted on a common member that engages the bearing support structure. The radially outer ends of the radially extending spokes are mounted on a fixed engine structure located radially outwardly of the bearing support structure. The radially extending spokes are held in tension and include a super elastic material to exert a radially inward restoring force on the bearing support structure, subsequent to any radial excursion of at least part of the fan shaft relative to an engine rotational axis (X) following any fracture of the frangible bolts.

Abstract: With an active magnetic bearing 1 there is a limit to the available rapidity of response to transient loadings upon a target or rotor 4. Thus, in accordance with the present invention, storage devices 25, 125, 225, 35 hold an electrical voltage VS significantly greater than the normal supply voltage V provided by a normal electrical source 22, 32. In such circumstances when a very large transient loading is detected on the bearing 1 a switch 26, 37 discharges the supply voltage VS across the coil 23, 33 in order that a more rapid increase and higher value inductance current IT is presented to the coil 22, 32 in response to that variable loading upon the target/rotor 24, 34. The electrical discharge from the storage device 25, 125, 225, 35 can be adjusted using the switch 26, 37 or mixing the storage devices 25, 125, 225, 35 as required for an appropriate discharge signal shape.

Abstract: With an active magnetic bearing 1 there is a limit to the available rapidity of response to transient loadings upon a target or rotor 4. Thus, in accordance with the present invention, storage devices 25, 125, 225, 35 hold an electrical voltage VS significantly greater than the normal supply voltage V provided by a normal electrical source 22, 32. In such circumstances when a very large transient loading is detected on the bearing 1 a switch 26, 37 discharges the supply voltage VS across the coil 23, 33 in order that a more rapid increase and higher value inductance current IT is presented to the coil 22, 32 in response to that variable loading upon the target/rotor 24, 34. The electrical discharge from the storage device 25, 125, 225, 35 can be adjusted using the switch 26, 37 or mixing the storage devices 25, 125, 225, 35 as required for an appropriate discharge signal shape.