A reinforcing structure made of a sheet-like cellular base material which comprises material attenuations (3) in a distribution over its area in a view from above, wherein the material attenuations sub-divide the base material into a multitude of material islands (1R; 1T) which are delineated from each other by the material attenuations (3) but are still connected to each other, wherein (a) the material islands (1R; 1T) are convex base polygons in a view from above; (b) a respective plurality of the material islands (1R; 1T) jointly form a convex and preferably regular compound polygon (1H) in a view from above; and (c) the compound polygons (1H) differ, in their number of corners and/or in a ratio of the lengths of their sides, from the base polygons which form the material islands (1R; 1T).

A reinforcing structure made of a sheet-like cellular base material which comprises material attenuations (3) in a distribution over its area in a view from above, wherein the material attenuations sub-divide the base material into a multitude of material islands (1R; 1T) which are delineated from each other by the material attenuations (3) but are still connected to each other, wherein (a) the material islands (1R; 1T) are convex base polygons in a view from above; (b) a respective plurality of the material islands (1R; 1T) jointly form a convex and preferably regular compound polygon (1H) in a view from above; and (c) the compound polygons (1H) differ, in their number of corners and/or in a ratio of the lengths of their sides, from the base polygons which form the material islands (1R; 1T).

A molded article of a fiber-reinforced resin contains at least a bundled aggregate [A] of discontinuous reinforcing fibers and a matrix resin [M], wherein the average layer thickness h in the molded article of the fiber-reinforced resin is 100 ?m or less and the CV value of the average layer thickness h is 40% or less; and a compression molding method therefor. It is possible to reliably and greatly reduce the occurrence of stress concentration in the molded article and to thereby achieve higher mechanical properties and further reduce variation in the mechanical properties.

A molded article of a fiber-reinforced resin contains at least a bundled aggregate [A] of discontinuous reinforcing fibers and a matrix resin [M], wherein the average layer thickness h in the molded article of the fiber-reinforced resin is 100 ?m or less and the CV value of the average layer thickness h is 40% or less; and a compression molding method therefor. It is possible to reliably and greatly reduce the occurrence of stress concentration in the molded article and to thereby achieve higher mechanical properties and further reduce variation in the mechanical properties.

A method of making a longitudinal reinforcing structure for a wind turbine blade. The method comprises a) providing an elongate master strip (62) of reinforcing material having substantially flat first and second surfaces, the distance between the first and second surfaces defining the thickness of the master strip; and b) dividing the master strip transversely to form a first strip and a shorter master strip, the respective strips being arranged end to end such that a trailing end of the first strip is located adjacent a new leading end of the master strip. The step of dividing the master strip comprises removing material from a dividing region extending through the entire thickness of the master strip, wherein the dividing region is shaped such that a chamfer (19c) at the trailing end (19b) of the first strip is created and a chamfer (63a) at the new leading end (63) of the master strip is created when the master strip is divided.

A method of making a longitudinal reinforcing structure for a wind turbine blade. The method comprises a) providing an elongate master strip (62) of reinforcing material having substantially flat first and second surfaces, the distance between the first and second surfaces defining the thickness of the master strip; and b) dividing the master strip transversely to form a first strip and a shorter master strip, the respective strips being arranged end to end such that a trailing end of the first strip is located adjacent a new leading end of the master strip. The step of dividing the master strip comprises removing material from a dividing region extending through the entire thickness of the master strip, wherein the dividing region is shaped such that a chamfer (19c) at the trailing end (19b) of the first strip is created and a chamfer (63a) at the new leading end (63) of the master strip is created when the master strip is divided.

A method of forming a fiber-reinforced molding compound. The method includes pre-impregnating carbon reinforcing fibers with a polymeric material to form one or more pre-impregnated continuous strands having at least 30% of the fibers protected by the polymeric material. The method further includes storing the one or more pre-impregnated continuous strands in bulk. The method also includes introducing the one or more pre-impregnated continuous strands into an extruder, forming a molding compound from the one or more pre-impregnated continuous strands, dispensing the molding compound from the extruder, and using the molding compound to produce a part.

A method of forming a fiber-reinforced molding compound. The method includes pre-impregnating carbon reinforcing fibers with a polymeric material to form one or more pre-impregnated continuous strands having at least 30% of the fibers protected by the polymeric material. The method further includes storing the one or more pre-impregnated continuous strands in bulk. The method also includes introducing the one or more pre-impregnated continuous strands into an extruder, forming a molding compound from the one or more pre-impregnated continuous strands, dispensing the molding compound from the extruder, and using the molding compound to produce a part.

A method of forming a fiber-reinforced molding compound. The method includes pre-impregnating reinforcing fibers with a polymeric material to form one or more pre-impregnated continuous tapes. The method further includes storing the one or more pre-impregnated continuous tapes in bulk, and introducing the one or more pre-impregnated continuous tapes into an extruder. The method further includes forming a molding compound from the one or more pre-impregnated continuous tapes, dispensing the molding compound from the extruder, and using the molding compound to produce a part.

A method of forming a fiber-reinforced molding compound. The method includes pre-impregnating reinforcing fibers with a polymeric material to form one or more pre-impregnated continuous tapes. The method further includes storing the one or more pre-impregnated continuous tapes in bulk, and introducing the one or more pre-impregnated continuous tapes into an extruder. The method further includes forming a molding compound from the one or more pre-impregnated continuous tapes, dispensing the molding compound from the extruder, and using the molding compound to produce a part.