Abstract: A deformable bi-stable device includes an elastically deformable member having at least two stable configurations and capable of being deformed from a first stable configuration to a second stable configuration, the element passing through an unstable configuration as it is deformed from the first stable configuration to the second stable configuration, and a shape memory polymer layer on or in the elastically deformable member. A method of using this device includes heating the shape memory polymer to a temperature sufficient to reduce the modulus of the shape memory polymer, deforming the deformable member to move from one of the first and second stable configurations to another of the first and second stable configurations, and cooling the device to a temperature sufficient to increase the modulus of the shape memory polymer.

Abstract: Active texturing systems adapted for selectively and reversibly modifying the texture of a surface utilizing a variably foldable structure in communication with the surface, and active material actuation to enable and/or cause folding.

Abstract: Active texturing systems adapted for selectively and reversibly modifying the texture of a surface utilizing a plurality of discrete mechanisms in communication with the reconfigurable structure.

Abstract: Actively controlled texturing systems for and methods of selectively and reversibly forming wrinkles, or modifying the amplitude, wavelength, or pattern of existing wrinkles upon a surface using active material actuation.

Abstract: In one embodiment, provided is an actively tunable acoustic attenuator having a frame, a membrane within the frame, and a mass secured to the membrane. In another embodiment, provided is an actively tunable acoustic attenuator having a frame, a membrane within the frame, and a mass secured to the membrane. The membrane is coupled, either indirectly or directly, to the frame via a variable stiffness coupler. In another embodiment, provided is an actively tunable acoustic attenuator having a frame and a plurality of membrane layers within the frame. An active material is between at least two of the plurality of membrane layers. A mass is secured to at least one of the plurality of membrane layers.

Abstract: An energy harvesting system for converting thermal energy to mechanical energy includes a heat engine that operates using a shape memory alloy active material. The shape memory alloy member may be in thermal communication with a hot region at a first temperature and a cold region at a second temperature lower than the first temperature. The shape memory alloy material may be configured to selectively change crystallographic phase between martensite to austenite and thereby one of contract and expand in response to the first and second temperatures. A thermal conduction element may be in direct contact with the SMA material, where the thermal conduction element is configured to receive thermal energy from the hot region and to transfer a portion of the received thermal energy to the SMA material through conduction.

Abstract: A reconfigurable bi-stable device includes an elastically deformable panel laterally disposed between and connected to one or more mounting members directly or indirectly connected to opposing ends of the panel, with the panel maintained under compressive force along at least one vector extending between the opposing ends. The compressive force deforms the panel into a one of two stable deformed positions, with the device disposed such that the panel may be moved between each of the two stable deformed positions by application of manual force to one of two opposing faces of the panel. A first shape memory alloy (SMA) or piezo actuator member is connected to the panel, the actuator member being capable of moving the panel from a first one of the two stable deformed positions to a second one of the two stable deformed positions.

Abstract: A reconfigurable bi-stable device includes an elastically deformable panel laterally disposed between and connected to one or more mounting members directly or indirectly connected to opposing ends of the panel, with the panel maintained under compressive force along at least one vector extending between the opposing ends. The compressive force deforms the panel into a one of two stable deformed positions, with the device disposed such that the panel may be moved between each of the two stable deformed positions by application of manual force to one of two opposing faces of the panel. A first shape memory alloy (SMA) or piezo actuator member is connected to the panel, the actuator member being capable of moving the panel from a first one of the two stable deformed positions to a second one of the two stable deformed positions.

Abstract: A heat engine includes a first rotatable pulley and a second rotatable pulley spaced from the first rotatable pulley. A shape memory alloy (SMA) element is disposed about respective portions of the pulleys at an SMA pulley ratio. The SMA element includes a first wire, a second wire, and a matrix joining the first wire and the second wire. The first wire and the second wire are in contact with the pulleys, but the matrix is not in contact with the pulleys. A timing cable is disposed about respective portions of the pulleys at a timing pulley ratio, which is different than the SMA pulley ratio. The SMA element converts a thermal energy gradient between the hot region and the cold region into mechanical energy.

Abstract: A shape memory alloy (SMA) heat engine includes a first rotatable pulley, a second rotatable pulley, and an SMA material disposed about the first and second rotatable pulleys and between a hot region and a cold region. A method of starting and operating the SMA heat engine includes detecting a thermal energy gradient between the hot region and the cold region using a controller, decoupling an electrical generator from one of the first and second rotatable pulleys, monitoring a speed of the SMA material about the first and second rotatable pulleys, and re-engaging the driven component if the monitored speed of the SMA material exceeds a threshold. The SMA material may selectively change crystallographic phase between martensite and austenite and between the hot region and the cold region to convert the thermal gradient into mechanical energy.

Abstract: An energy harvesting system includes a heat engine and a component configured to be driven by operation of the heat engine. The heat engine includes a first member, a second member, a shape memory alloy material, and a tensioner. The second member is spaced from the first member. The shape memory alloy material operatively interconnects the first member and the second member. The shape memory alloy material is configured to selectively change crystallographic phase from martensite to austenite and thereby contract in response to exposure to a first temperature. The shape memory alloy material is also configured to selectively change crystallographic phase from austenite to martensite and thereby expand in response to exposure to a second temperature. The tensioner is configured to apply tension to the shape memory alloy material as the shape memory alloy material selectively expands and contracts such that the shape memory alloy material is taut.

Abstract: An energy harvesting system includes a heat engine and a component. The heat engine includes a belt, a first member, and a second member. The belt includes a strip of material and at least one wire at least partially embedded longitudinally in the strip of material. The wire includes a shape memory alloy material. A localized region of the at least one wire is configured to change crystallographic phase between martensite and austenite and either contract or expand longitudinally in response to exposure to a first temperature or a second temperature such that the strip of material corresponding to the localized region also contracts or expands. The first member is operatively connected to the belt and moves with the belt in response to the expansion or contraction of the belt. The component is operatively connected to the first member such that movement of the first member drives the component.

Abstract: An energy harvesting system comprises a first region and a second region having a temperature difference therebetween. A plurality of heat engines are located proximate to the conduit and configured for converting thermal energy to mechanical energy. The heat engines each include a shape memory alloy forming at least one generally continuous loop. The shape memory alloy driven to rotate by heat exchange contact with each of the first region and the second region. At least one pulley for each of the plurality of heat engines is driven by the rotation of the respective shape memory alloy, and each of the at least one pulleys is operatively connected to a component to thereby drive the component.

Abstract: A panel structure includes a composite facesheet and a stiffening core having a plurality of core members in an intersecting web configuration provided on the composite facesheet.

Abstract: An energy harvesting system includes a heat engine and a component. The heat engine includes a belt, a first member, and a second member. The belt includes a strip of material and at least one wire at least partially embedded longitudinally in the strip of material. The wire includes a shape memory alloy material. A localized region of the at least one wire is configured to change crystallographic phase between martensite and austenite and either contract or expand longitudinally in response to exposure to a first temperature or a second temperature such that the strip of material corresponding to the localized region also contracts or expands. The first member is operatively connected to the belt and moves with the belt in response to the expansion or contraction of the belt. The component is operatively connected to the first member such that movement of the first member drives the component.

Abstract: In one embodiment, provided is an actively tunable acoustic attenuator having a frame, a membrane within the frame, and a mass secured to the membrane. In another embodiment, provided is an actively tunable acoustic attenuator having a frame, a membrane within the frame, and a mass secured to the membrane. The membrane is coupled, either indirectly or directly, to the frame via a variable stiffness coupler. In another embodiment, provided is an actively tunable acoustic attenuator having a frame and a plurality of membrane layers within the frame. An active material is between at least two of the plurality of membrane layers. A mass is secured to at least one of the plurality of membrane layers.

Abstract: A heat engine includes a first rotatable pulley and a second rotatable pulley spaced from the first rotatable pulley. A shape memory alloy (SMA) element is disposed about respective portions of the pulleys at an SMA pulley ratio. The SMA element includes first spring coil and a first fiber core within the first spring coil. A timing cable is disposed about disposed about respective portions of the pulleys at a timing pulley ratio, which is different than the SMA pulley ratio. The SMA element converts a thermal energy gradient between the hot region and the cold region into mechanical energy.

Abstract: A device for selectively controlling and varying a frictional force level at an interface between two bodies, includes a first contact body having at least one surface, a second contact body having at least one surface in physical communication with the first contact body, and an active material in operative communication with a selected one or both of the first contact body and the second contact body, wherein the active material is configured to undergo a change in a property upon receipt of an activation signal wherein the change in a property is effective to change the frictional force level at the interface between the at least one surface of the first contact body and the at least one surface of the second contact body.

Abstract: An active interface control shiftable between deployed and stowed configurations, and including an active material actuator employing a bi-stable mechanism configured to increase the actuator stroke length, and/or presenting intrinsic or external sensing capability, and reconfigurable displays comprising separately shiftable sets of controls.

Abstract: A reconfigurable bi-stable device includes an elastically deformable panel laterally disposed between and connected to one or more mounting members directly or indirectly connected to opposing ends of the panel, with the panel maintained under compressive force along at least one vector extending between the opposing ends. The compressive force deforms the panel into a one of two stable deformed positions, with the device disposed such that the panel may be moved between each of the two stable deformed positions by application of manual force to one of two opposing faces of the panel. A first shape memory alloy (SMA) or piezo actuator member is connected to the panel, the actuator member being capable of moving the panel from a first one of the two stable deformed positions to a second one of the two stable deformed positions.