A reinforcing structure for a wind turbine blade is in the form of an elongate stack of layers of pultruded fibrous composite strips supported within a U-shaped channel. The length of each layer is slightly different to create a taper at the ends of the stack; the centre of the stack has five layers, and each end has a single layer. The ends of each layer are chamfered, and the stack is coated with a thin flexible pultruded fibrous composite strip extending the full length of the stack. The reinforcing structure extends along a curved path within the outer shell of the blade. The regions of the outer shell of the blade on either side of the reinforcing structure are filled with structural foam, and the reinforcing structure and the foam are both sandwiched between an inner skin and an outer skin.

A method for producing a hollow composite structure, such as a spar beam for a wind turbine blade, includes placing a membrane within a mold tool, the membrane being permeable to air and impermeable to resin. A mandrel is placed within the mold tool, the mandrel enclosed in an air tight layer that includes a vent. Fiber reinforcement material is placed around the mandrel within the mold tool and the membrane is sealed at least partly around the fiber reinforcement material and mandrel. The mold tool is closed with the vent line from the mandrel extending through the sealed membrane to outside of the mold tool. A vacuum is drawn in the mold tool while the mandrel is vented to outside of the mold tool, and while the vacuum is being drawn, resin is infused into the mold tool around the mandrel such that the resin is drawn towards the membrane.

A method and system for fabricating a composite structure is provided. A first vacuum bag is laid down on a surface of a tool. A composite material is positioned on top of the first vacuum bag on the tool. A second vacuum bag covers the composite material. Vacuum pressure is applied to the first vacuum bag and the second vacuum bag. The composite material is cured to form the composite structure. The first vacuum bag is inflated with compressed air to lift the composite structure from the tool.

A gripping device (76) is provided for lifting a preform for a wind turbine blade from a preform mould (71). The gripping device (76) comprises a base frame (62), a plurality of arms (78) slidably mounted on the base frame (62), each arm (78) having a proximal end and a distal end, a plurality of gripping members (86) for gripping a top surface (75) of the preform. The vertical position of one or more arms (78) of the gripping device (76) relative to the base frame (62) may change when lowering the gripping device (76) towards a preform to reflect the top surface (75) of the perform.

A resin impregnation measurement device includes a jig and a resin impregnation sensor. The jig is formed into an inner surface shape of a protrusion of a stringer. The jig includes outer surfaces including a facing surface that is to face an inner surface of the protrusion. The resin impregnation sensor is disposed on the facing surface of the jig.

An apparatus for processing a composite structure includes a mandrel that includes a tooling surface and vacuum bagging that includes an elastomeric membrane and a bagging surface. The apparatus also includes a surface interface formed between the mandrel and the elastomeric membrane. The surface interface includes a suction channel formed in at least one of the tooling surface of the mandrel and the bagging surface of the elastomeric membrane. The elastomeric membrane is configured to be sealed to the mandrel along the suction channel in response to a vacuum applied to the suction channel.

A covering device for a component space in a tool for producing fiber composite components is a multi-layer pre-fabricated material cloth provided with a gas-permeable, matrix material-impermeable membrane. A gas-impermeable, matrix material-impermeable film is provided. Membrane and film are connected at their circumferential rims to delimit an evacuation space with a flow aid and closed by a matrix material-tight connection. Gas having passed from the component space through the membrane into the evacuation space is evacuated through an opening of the film away from the component space. A contact element arranged at a side of the film facing away from the evacuation space surrounds the opening of the film. It is connected matrix material-tightly to the film. The contact element has a contact surface at a side facing away from the film for attaching the covering device to an inner side of a tool wall delimiting the component space.

The present invention relates to an interlayer sheet for a spar cap comprising: a first fibre layer comprising a first plurality of fibres, having a first upper fibre surface and a first lower fibre surface, a second fibre layer comprising a second plurality of fibres, having a second upper fibre surface and a second lower fibre surface. The first fibre layer is arranged on top of the second fibre layer, such that the first lower fibre surface is in contact with the second upper fibre surface. The first fibre layer is of a different characteristic than the second fibre layer. Furthermore, the present invention relates to a spar cap for a wind turbine blade, comprising a plurality of pre-cured fibre-reinforced elements including at least a first pre-cured fibre-reinforced element and a second pre-cured fibre-reinforced element; and a number of interlayer sheets arranged between the plurality of pre-cured fibre-reinforced elements.

A composite material molding jig for molding a long member made of a fiber base material and a resin on a plate member includes: a first member that is made of a material having a thermal expansion coefficient equivalent to a thermal expansion coefficient of the long member, internally includes a space serving as a mold of the long member, and has an outer surface formed flat in a longitudinal direction; and a second member that is made of a material lighter than the material of the first member, internally includes a space shaped to contain the first member, and has an inner surface formed flat in the longitudinal direction, wherein the fiber base material is placed in the space inside the first member, and the first member is placed in the space inside the second member for molding the long member.

The present disclosure relates to a spar cap (10) for a wind turbine blade (1000) comprising: a plurality of spar cap layers (20) and a first interlayer (30) arranged between the first spar cap layer (20a) and the second spar cap layer (20b) and comprising: a number of first interlayer areas (31), including a first primary interlayer area (31a), comprising a first number of interlayer sheets (33) comprising a first plurality of fibres (35); and a number of second interlayer areas (32), including a second primary interlayer area (32a), comprising a second number of interlayer sheets (34) comprising a second plurality of fibres (36), wherein the first number of interlayer sheets (33) is of a different characteristic than the second number of interlayer sheets (34).