Abstract: A method and apparatus for controlling the blowing of compressed air from an aerodynamic structure such as an aircraft wing or helicopter rotor blade and thus controlling the aerodynamic properties of the wing comprises a narrow slot (13) in the upper surface 915) of the structure near its trailing edge (14). Inside the wing (12) is a chamber (23) that is connected to the narrow slot (13) in the wing surface (15). The chamber (23) houses a compressed air conduit (16) for supplying and holding compressed air. A passageway (25) connects the conduit (16) to the slot (13) in the upper surface (25) of the wing (12). The lower wall (27) of the passage (25) has a slit (32) allowing a shutter (31) to move selectively into the passage (25) and obstruct the flow of compressed air through the passageway (25). The shutter (31) is attached to a smart material actuator comprising a piezoelectrical bender (29). When a control voltage is applied to the bender (29), the bender (29) will bend.

Abstract: A tailored structural member that is designed to generate a yield-type response, with applicability to the arrest of a moving body. The structural member comprises a primary load path connected in parallel to a longer secondary load path at a pair of common nodes. The primary load path is designed to fail at a lower load than that required to fail the secondary load path when subjected to a tensile force. As a result of the load redistribution achieved through the use of the redundant paths provided by the primary and secondary load paths, the structural member dissipates more kinetic energy from the moving body within a given set of displacement and deceleration force constraints than is possible using a conventional, uniform cross-section member.

Abstract: An improved rotational displacement apparatus is provided for measuring accurately the twist induced in an extension-twist coupled specimen in response to application of an axial load. The apparatus has an internal cylinder within which a piston rides. A piston rod extends from the piston through a pair of radial ball bearings in the base of the cylinder block to a free end outside the cylinder block. The piston is sized to be slightly smaller in diameter than the cylinder to provide a small space between the piston and the cylinder walls. A part for supplying compressed air to the region of the cylinder below the piston and a part for venting air from the region of the cylinder above the piston are provided. An optical encoder is coupled to measure rotational motion of the piston within the cylinder. In use, the apparatus is mounted in a testing machine and a specimen to be tested is secured at one end to the free end of the piston rod and at its other end to the mounting block of the testing machine.

Abstract: A method and apparatus for controlling the blowing of compressed air from an aerodynamic structure such as an aircraft wing or helicopter rotor blade and thus controlling the aerodynamic properties of the wing comprises a narrow slot (13) in the upper surface (15) of the structure near its trailing edge (14). Inside the wing (12) is a chamber (23) that is connected to the narrow slot (13) in the wing surface (15). The chamber (23) houses a compressed air conduit (16) for supplying and holding compressed air. A passageway (25) connects the conduit (16) to the slot (13) in the upper surface (15) of the wing (12). The lower wall (27) of the passage (25) has a slit (32) allowing a shutter (31) to move selectively into the passage (25) and obstruct the flow of compressed air through the passageway (25). The shutter (31) is attached to a smart material actuator comprising a piezoelectrical bender (29). When a control voltage is applied to the bender (29), the bender (29) will bend.

Abstract: This invention comprises an improved rotational displacement apparatus for measuring accurately the twist induced in an extension-twist coupled specimen in response to application of an axial load. The apparatus has an internal cylinder within which a piston rides. A piston rod extends from the piston through a pair of radial ball bearings in the base of the cylinder block to a free end outside the cylinder block. The piston is sized to be slightly smaller in diameter than the cylinder to provide a small space between the piston and the cylinder walls. Means for supplying compressed air to the region of the cylinder below the piston and means for venting air from the region of the cylinder above the piston are provided. An optical encoder is coupled to measure rotational motion of the piston within the cylinder.