The present technology provides an acoustic transmission member that includes a core layer layered between two skin layers, the skin layers being formed of a material having a higher elastic modulus than a material of the core layer. A thickness ds of the skin layers is formed such that Equation (1) is satisfied, where f is the center frequency of the transmission frequency band, cw is the acoustic velocity in the medium surrounding the acoustic transmission member, is the wavelength corresponding to the center frequency in the medium, Cds is the longitudinal wave acoustic velocity in the skin layer, and n is a discretionary natural number. $\begin{array}{cc}\mathrm{ds}=\frac{n}{2}\frac{\mathrm{Cds}}{\mathrm{cw}}=\frac{n}{2}\frac{\mathrm{Cds}}{f}& \left(1\right)\end{array}$

The present technology provides an acoustic transmission member that includes a core layer layered between two skin layers, the skin layers being formed of a material having a higher elastic modulus than a material of the core layer. A thickness ds of the skin layers is formed such that Equation (1) is satisfied, where f is the center frequency of the transmission frequency band, cw is the acoustic velocity in the medium surrounding the acoustic transmission member, is the wavelength corresponding to the center frequency in the medium, Cds is the longitudinal wave acoustic velocity in the skin layer, and n is a discretionary natural number. $\begin{array}{cc}\mathrm{ds}=\frac{n}{2}\frac{\mathrm{Cds}}{\mathrm{cw}}=\frac{n}{2}\frac{\mathrm{Cds}}{f}& \left(1\right)\end{array}$

A method for forming a vacuum insulated structure using a prepared core material includes preparing a powder insulation material defining a bulk density, pre-densifying the powder insulation material to form a pre-densified insulation base, crushing the pre-densified insulation base into granular core insulation to define a core density of the granular core insulation, disposing the granular core insulation having the core density into an insulating cavity defined within an insulating structure and expressing gas from the interior cavity of the insulating structure to further densify the granular core insulation to define a target density. The granular core insulation defines the target density disposed within the insulating structure defines the vacuum insulation structure, wherein the target density defines a density in the range of from approximately 80 grams per liter to approximately 350 grams per liter.

A pultruded strip (50) of reinforcing material for stacking with one or more similar strips (50) to form a spar cap for a wind turbine blade is disclosed. The pultruded strip comprises a core (56) comprising fibres (58) disposed in a resin matrix (60) and a sacrificial layer (52) at least partially covering one or more surfaces of the core (56). The sacrificial layer (52) is a resin layer defining an adherend surface (62A) of the strip. A pultrusion process for making such a strip (50) comprises drawing resin-coated reinforcing fibres (58) through a pultrusion die (80) in a process direction to form a core (56) of the strip (50) and applying further resin (53) to one or more surfaces of the core (56) to form a sacrificial resin layer (52) defining an adherend surface (62A) of the strip (50).

A method of manufacturing a cured composite structure includes placing a radius filler element into a radius cavity extending along a length of a composite base member formed of dry fiber material comprised of reinforcing fibers. The radius filler element is formed of a radius filler material. The method also includes infusing resin into the dry fiber material, and chemically reacting the resin with the radius filler material to create a mixture of resin and radius filler material along side surface interfaces between the radius filler element and the composite base member. The method additionally includes curing or solidifying the resin, and allowing solvent in the resin to evaporate causing hardening of the mixture and bonding of the radius filler element to the composite base member, and resulting in a cured composite structure.

A device (10) comprising a carrier material (14) and a matrix material (12) deposited onto the carrier material in a pattern that leaves a predetermined amount of space (18) between each deposition of matrix material.

A positioning jig (25) and a method for manufacturing a wind turbine blade comprising moulding a first and a second blade shell portion in respective first and second mould tools; positioning a shear web (15) in a spanwise direction within a first shell portion (20) in a said first mould tool (7); anchoring said shear web in position in said first shell portion; and closing said second shell portion (21) over said first shell portion to thereby generate a wind turbine blade shell defining a chordwise extent between a in trailing edge and a leading edge thereof, and a spanwise extent between a root region and a tip thereof and wherein said shear web, bordered by a first (24) and a second longitudinal edge, extends in a thickness direction of said blade; said method further comprising: providing a positioning jig; and securing said positioning jig to said shear web, prior to its introduction into said first shell portion and guiding said shear web into its predetermined standing position in said first shell portion, with its first longitudinal edge adjacent said first shell portion, by engaging a reference surface (33) of said positioning jig with a locating surface (12) at said first mould tool thereby to bring said positioning jig into its guide position with said shear web in its predetermined standing position; and removing said positioning jig from said first mould tool prior to closing said second shell portion over said first shell portion. A shear web, especially an upper edge thereof, may be additionally secured to the blade shell using ligaments (30) prior to removal of the positioning jig.

A method for manufacturing a rotor blade panel of a wind turbine includes placing one or more fiber-reinforced outer skins into a mold of the rotor blade panel. The method also includes printing and depositing, via a computer numeric control (CNC) device, a plurality of rib members that form at least one three-dimensional (3-D) reinforcement grid structure onto an inner surface of the one or more fiber-reinforced outer skins. Further, the grid structure bonds to the one or more fiber-reinforced outer skins as the grid structure is deposited. Moreover, the method includes printing at least one additional feature into the grid structure.

Various embodiments disclosed relate to a method of forming a composite including a carbon composite structure. The method includes disposing a precursor composition on a substrate. The composition includes a porogen component, a carbon component, and a catalyst component. The method further includes irradiating the precursor composition to form the carbon composite structure.

An additively manufactured (AM) hybrid composite structure is disclosed. The AM hybrid composite structure includes a first portion and a second portion. The second portion includes one or more AM elements which are configured to enable integration of the second portion with the first portion to form an integrated component including both the second portion and the first portion. A method of manufacturing a hybrid composite structure is disclosed. The method includes manufacturing a first portion, and additively manufacturing a second portion. The step of additively manufacturing the second portion includes co-printing one or more AM elements. The method further includes using the one or more AM elements as a part of a tool to integrate the first portion with the second portion, and forming an integrated component including both the first portion and the second portion.