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: In some examples, techniques and architectures for fabricating an image sensor chip having a curved surface include placing a substrate on a first surface of an image sensor chip, wherein the first surface of the image sensor chip is opposite a second surface of the image sensor chip, and wherein the second surface of the image sensor chip includes light sensors to generate electrical signals in response to receiving light. Fabricating also includes modifying a volume of the substrate so as to impart forces on the image sensor chip to produce a curved image sensor chip.

Abstract: An acoustic barrier structure can include a support structure that defines a plurality of cells, a weight attached to the support structure, and at least one resonant membrane covering one of the plurality of cells. The at least one resonant membrane can comprise at least one weight. The at least one resonant membrane can have an anti-resonant frequency and the support structure with the weight can provide wide frequency band gaps between odd resonance modes while suppressing structure-membrane coupled modes to enable the anti-resonance of the at least one resonant membrane.

Abstract: Composite materials with high damping and high stiffness at relatively low density. These materials include three-dimensional structures of interconnected ligaments, which have multiple concentric layers alternating between stiff constraining layers and soft damping layers, so that bulk deformation of the structure results in high local shear strain and correspondingly high bulk damping.

Abstract: Some on-vehicle devices, such as air dams, air spoilers, and HVAC system baffles, may have movable components that are pulled from one position to another by shrinkage of a linear shape memory alloy (SMA) actuator. Upon an activation signal, the shrinkage of the SMA actuator occurs when it is resistance heated by an electrical current. It is found that useful information concerning the overall intended operation of the on-vehicle device may be obtained by computer analysis of the temporal variation of both current flow through the actuator and its electrical resistance as it is heated to perform its function in the device. A comparison of present current flow and variation of resistance, during activation of the device, with prescribed stored values can reveal malfunction of components of the device as it is being used, in place, on the vehicle.

Abstract: A hybrid acoustic absorption and reflection resonator can includes a rigid structure defining a cell, a membrane with at least one orifice attached to the rigid structure, and a back sheet attached to the rigid structure and covering the cell. The membrane is configured to reflect acoustic waves in a predetermined range of frequencies. The rigid structure, the membrane, and the back sheet define a Helmholtz cavity; the Helmholtz cavity is configured to absorb acoustic energy at a frequency within the predetermined range of frequencies.

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: In one embodiment, provided is a sound attenuating barrier having a core structure between face sheets with a mass attached to at least one face sheet, and having a spatially varied stiffness distribution and/or a spatially varied density. The sound attenuating barrier may include at least one face sheet and/or core having a spatially varied stiffness distribution and/or a spatially varied mass distribution. In one embodiment, a sound attenuating barrier is provided having a core structure between face sheets with a mass structure attached to at least one face sheet, with the core/and or face sheet(s) being constructed to design an effective vibration length as well as enable a variable local stiffness and mass across the sound attenuating barrier such that the sandwich structure provides variable resonance frequency responses and broadband coverage.

Abstract: Composite materials with high damping and high stiffness at relatively low density. These materials include three-dimensional structures of interconnected ligaments, which have multiple concentric layers alternating between stiff constraining layers and soft damping layers, so that bulk deformation of the structure results in high local shear strain and correspondingly high bulk damping.

Abstract: A microstructured reconfigurable or morphing composite material with controlled anisotropic deformation properties. The composite material provides highly controlled deformation and stiffness properties. Microscopic three dimensional structures are included in the composite material to control its deformation kinematics and stiffness properties. The composite material has highly segregated in-plane and out-of-plane stiffness properties.

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 method of testing a shape memory alloy (SMA) actuated device includes cyclically operating the device. The method further includes determining a number of cycles in a functional life of the device based on observations of the device during the cyclical operation. The functional life is a range of consecutive cycles of operation of the device beginning with a first cycle during which the device performs within a specified limit. The functional life is immediately followed by a cycle during which the device performs outside of the specified limit. The method still further includes applying a progressive substitution sub-process to identify an opportunity to increase the number of cycles in the functional life of the device.

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 variable stiffness structure configured to support a variable load, the variable stiffness structure including a positive stiffness element coupled to the variable load, a negative stiffness element, a hydraulic system coupled to the positive and negative stiffness elements and configured to adjust a relative position of the positive and negative stiffness elements in response to a change in the variable load, while the variable stiffness structure supports the variable load.

Abstract: A photonic device is provided having a two or three-dimensionally periodic structure of interconnected members with alterable spacing between the members. The structure is composed of a shape memory polymer configured to be thermo-mechanically tunable to display a plurality of optical properties under a series of temperature changes and stress. A method of producing a photonic device based on a shape memory polymer is provided. A mold, having a two or three-dimensionally periodic structure of interconnected components with a characteristic spacing between the components, is infiltrated with a shape memory polymer precursor to form a composite structure. The composite structure is solidified. The mold is removed from the composite structure to form a photonic device as an inverse replica of the mold.

Abstract: Mechanical devices powered by Shape Memory Alloy (SMA) wires or other linear elements offer advantages in automotive applications. Such SMA-powered devices are commonly reliable and long-lived but have a finite lifetime. Measurements of the electrical resistivity of an SMA element during operation of the element may be related to the remaining lifetime of the element. Because operation of SMA elements is promoted by heating the element, usually by passage of an electric current, the resistivity measurements, and hence assessment of SMA element operation, may be made without interruption to the operation of the SMA-powered device and without addition of dedicated sensors.

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: Shape memory alloy (SMA) actuating elements are commonly simpler and of lower mass than alternative actuator designs and may find particular application in the transportation industry. Such SMA-powered devices are usually reliable and long-lived but the phase transformations which occur in the SMA alloy and are responsible for its utility are not totally reversible. This irreversibility, a consequence of irrecoverable strain, may progressively degrade the long-term actuator performance as the irrecoverable strain accumulates over many operating cycles. Methods and devices for compensating for these effects and extending the useful cycle life of SMA actuators are described.

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.