Abstract: Solid, flexible composite structures may include a textile arrangement of at least one textile layer constructed of textile fibers and having a distribution of pores formed therein, with a first resin filling pores having a pore diameter equal to or less than a pore diameter threshold, and a second resin bonded to the first resin and substantially filling pores having a pore diameter greater than the pore diameter threshold. Some embodiments include a rigid first resin such as an epoxy, and a flexible second resin such as a silicone. Methods of producing composite structures may include selectively filling, in a textile layer having a number of pores formed therein, only those pores having a pore diameter equal to or less than a pore diameter threshold, with a first resin, and substantially filling the remaining pores in the textile layer with a second resin.

Abstract: A deformable component which is initially flat and which can be caused to buckle by the application of a radially inward preload force, applied using an outer clamp. The deformable component in the buckled configuration then exhibits negative stiffness over a portion of its range of travel, when an axial force is applied. The deformable component may be fabricated from metal sheet, and may take the form of a polygonal central portion and at least two arms extending radially outwards.

Abstract: An apparatus has a first structure, a second structure, and an activated seal. The second structure has a first position adjacent to the first structure such that the first structure is not in contact with the second structure. The activated seal is attached to at least one of the first structure and the second structure. The activated seal has a variable stiffness that may be changed in response to a stimuli such that the activated seal is capable of being deformed when at least one of the first structure and the second structure are moved relative to each other.

Abstract: Knit fabrics having ceramic strands, thermal protective members formed therefrom and to their methods of construction are disclosed. Methods for fabricating thermal protection using multiple materials which may be concurrently knit are also disclosed. This unique capability to knit high temperature ceramic fibers concurrently with a load-relieving process aid, such as an inorganic or organic material (e.g., metal alloy or polymer), both small diameter wires within the knit as well as large diameter wires which provide structural support and allow for the creation of near net-shape performs at production level speed. Additionally, ceramic insulation can also be integrated concurrently to provide increased thermal protection.

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: A thermal protection system is provided. The thermal protection system includes a thermally insulative core structure, at least one layer of impact-resistant material coupled to the thermally insulative core structure, and at least one layer of composite material at least partially encapsulating the thermally insulative core structure and the at least one layer of impact-resistant material.

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: A method of controlling an energy harvesting system that converts excess thermal energy into mechanical energy and includes a Shape Memory Alloy (SMA) member, includes obtaining current operational parameters of the energy harvesting system, such as a maximum temperature, a minimum temperature and a cycle frequency of the SMA member. The current operational parameters are compared to a target operating condition of the energy harvesting system to determine if the current operational parameters are within a pre-defined range of the target operating condition. If the current operational parameters are not within the pre-defined range of the target operating condition, then a heat transfer rate to, a heat transfer rate from or a cycle frequency of the SMA member is adjusted to maintain operation of the energy harvesting system within the pre-defined range of the target operating condition to maximize efficiency of the energy harvesting system.

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: An energy harvesting system comprises a first region having a first temperature and a second region. A conduit is located at least partially within the first region. A heat engine configured for converting thermal energy to mechanical energy includes a shape memory alloy forming at least one generally continuous loop. The shape memory alloy is disposed in heat exchange contact with the first region and the second region. The shape memory alloy is driven to rotate around at least a portion of the conduit by the response of the shape memory alloy to the temperature difference between the first region and the second region. At least one pulley is driven by the rotation of the shape memory alloy, and the at least one pulley is operatively connected to a component to thereby drive 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 method of controlling and/or predicting the remaining useful life of an active material actuator, such as a shape memory alloy wire, includes obtaining historical actuation data of an inherent system variable, such as electrical resistance, over a secondary variable, such as time, determining a normal operating envelope having upper and lower bounds based on the data, determining a current profile for a given actuation cycle, and comparing the shape of the current profile to the envelope to determine an out-of-bounds event.

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: A hydraulic actuator includes a tubular bladder having first and second ends, an expandable and collapsible sleeve provided on the tubular bladder, a fluid inlet fitting provided in fluid communication with the tubular bladder and at least one mechanical connection provided along the tubular bladder. The hydraulic actuator may have flexibility and an overall diameter of less than about 5 mm.

Abstract: Solid, flexible composite structures may include a textile arrangement of at least one textile layer constructed of textile fibers and having a distribution of pores formed therein, with a first resin filling pores having a pore diameter equal to or less than a pore diameter threshold, and a second resin bonded to the first resin and substantially filling pores having a pore diameter greater than the pore diameter threshold. Some embodiments include a rigid first resin such as an epoxy, and a flexible second resin such as a silicone. Methods of producing composite structures may include selectively filling, in a textile layer having a number of pores formed therein, only those pores having a pore diameter equal to or less than a pore diameter threshold, with a first resin, and substantially filling the remaining pores in the textile layer with a second resin.

Abstract: An exhaust system configured for converting thermal energy to mechanical energy includes a source of thermal energy provided by a temperature difference between an exhaust gas having a first temperature and a heat sink having a second temperature that is lower than the first temperature. The exhaust system also includes a conduit configured for conveying the exhaust gas, a heat engine disposed in thermal relationship with the conduit and configured for converting thermal energy to mechanical energy, and a member disposed in contact with the conduit and configured for conducting thermal energy from the conduit to the heat engine. The heat engine includes a first element formed from a first shape memory alloy having a crystallographic phase changeable between austenite and martensite at a first transformation temperature in response to the temperature difference between the exhaust gas and the heat sink.

Abstract: A cooling system configured for converting thermal energy to mechanical energy includes a source of thermal energy provided by a temperature difference between a heat source having a first temperature and a coolant having a second temperature that is lower than the first temperature. The cooling system includes a cooling circuit configured for conveying the coolant to and from the heat source. The cooling circuit includes a conduit and a pump in fluid communication with the conduit and configured for delivering the coolant to the heat source. The cooling system also includes a heat engine disposed in thermal relationship with the conduit and configured for converting thermal to mechanical energy. The heat engine includes a first element formed from a first shape memory alloy having a crystallographic phase changeable between austenite and martensite at a first transformation temperature in response to the temperature difference between the heat source and coolant.

Abstract: An adaptive structural core includes a plurality of core members arranged in a repeating pattern, a plurality of actuator attachment points provided on the plurality of core members and at least one actuator engaging the plurality of actuator attachment points.

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.