Structural preform layers of multiple rigid unidirectional strength elements or rods are constructed and arranged for use in fabricating load-bearing support structures and reinforcements of wind turbine blades. Individual preform layers include multiple elongate unidirectional strength elements or rods arranged in a single layer along a longitudinal axis of the preform layer. Each preform layer includes one or more fibrous carrier layers to which the multiple strength elements or rods are joined and arranged in the single layer. Each strength element or rod is longitudinally oriented and adjacent to other elements or rods. Individual strength elements or rods include a mass of substantially straight unidirectional structural fibers embedded within a matrix resin such that the elements or rods have a substantially uniform distribution of fibers and high degree of fiber collimation. The relative straightness of the fibers and fiber collimation provide strength elements or rods and the preform layers with high rigidity and significant compression strength.

Wind turbine rotor blade components and methods of making same

A method of transferring an uncured composite laminate skin from a lay-up surface of a male mandrel tool to a female cure tool includes defining multiple vacuum zones on the lay-up surface, each zone corresponding to one of a multiple of portions into which the skin is to be separated. For example, to separate the skin into two portions, a low profile seal of a first membrane to the lay-up surface is formed at a first vacuum zone and a second low profile seal for a second membrane is formed at a second vacuum zone. The method further includes laying up a composite laminate skin over all the vacuum zones; separating the composite laminate skin into portions, for example, a first portion over the first vacuum zone and a second portion over the second vacuum zone; and releasing the portions individually into cure tools having an outside mold line surface.

Method of transferring large uncured composite laminates

A composite spar for a helicopter rotor blade includes upper and lower sidewall regions (40, 42) and forward and aft conic regions (45, 47) wherein the conic regions further define transition and closure subregions (50, 52). Constant width crossplies (62) and unidirectional plies (72) are stacked and arranged to form crossply and unidirectional laminates (60, 70). The crossply laminates (60) form the upper and lower sidewall regions (40, 42) and end portions thereof extend into the forward and aft conic regions (45, 47) to form a staggered distribution of structural joints (68) and slip plane interfaces (66) therein. The crossply laminates are comprised of high modulus fibers which are oriented within a range of +/- 42° to about +/- 38 ° relative to the longitudinal axis (25) of the composite spar (10). The unidirectional laminates (70) form the upper and lower sidewall regions (40, 42) and have end portions (72e) extending into the transition subregions (50). The unidirectional laminates (70) are interposed between the crossply laminates (60) and comprised of a mix of high and low modulus fibers which are oriented substantially parallel to the longitudinal axis (25). Furthermore, plies of reinforcing fabric (80) having low modulus fibers oriented above about 80° relative to the longitudinal axis (25) may be disposed between the unidirectional plies (72) of the unidirectional laminate (70). The composite spar is manufactured in molds.

Fiber reinforced composite spar for a rotary wing aircraft and method of manufacture thereof

The method of fabricating a complex part made of composite material and having a plurality of panels oriented in diverse angular relationship, and utilizing a plurality of conformable cauls upon which the composite material is individually laid up and which cauls cooperate to form one of the molds used in the co-curing of the individually laid-up composite materials.

Method of fabricating a complex part made of composite material

Aircraft empennage structures have impact resistance satisfying transport aircraft certification requirements (for example, FAR part 25 and/or other international certification requirements). The structures may be specifically embodied in leading edge structures that are preferably in the form of one-piece components formed from fiber-reinforced composite materials (e.g., reinforcement fibers such as glass fibers, aramid fibers and/or carbon fibers embedded in a polymeric matrix such as an epoxy resin). The leading edge structures will most preferably include an arcuate skin and longitudinally extending internal reinforcement which is generally Y-shaped and includes a planar rib element and a pair of planar divergent reinforcement arms. The rib element may be positioned so as to be coplanar with a longitudinal bisecting plane of the leading edge structure. A forward end of the rib element may thus be integrally attached aft of an apical end of the skin, whereas an aft end of the rib may be integrally attached to each of the reinforcement arms. According to certain embodiments, rigidity and thus impact resistance may be facilitated by providing the apical end of the skin with a greater cross-sectional thickness as compared to the attachment ends of the skin.

Impact resistant aircraft leading edge structures and aircraft including the same

This invention relates to an improved composite material leading edge/spar member for an aircraft control surface, and the like. The present invention provides a one-piece composite leading edge/spar member that is of a lighter and stronger construction offering dimensional stability, and an efficient method for manufacturing the same is also provided. A one-piece leading edge/spar member (12) includes a forward leading edge portion (22), and an aft spar portion (23). The forward leading edge and the aft spar portions are connected together as a continuous one-piece tubular member of composite material. The forward leading edge portion (22) may be rounded, and the aft spar portion (23) may include an aft web portion (24) and first and second rebate portions (26, 28). The rebate portions (26, 28) connect the web portion (24) to the rounded forward leading edge portion (22), and provide surfaces for the attachment of skin surface members (16, 18) thereto.

Richard Jensen

Papers

Composite leading edge/spar member for an aircraft control surface