Abstract: A method of manufacturing a load cell assembly and methods of folding a circuit device are disclosed. A flexible circuit body including a strip having at least one hinge is provided, with the strip being in a first position or an unfolded position. A plurality of strain gauges are attached to the strip, with the hinge disposed between the strain gauges. A jig is provided and the strip of the flexible circuit body is folded along the hinge utilizing the jig to define a second position or folded position of the strip.

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: 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: A sensor system includes a housing defining a cavity, an actuator formed from an alloy transitionable between first and second states, a plunger attached to the actuator, and a resilient member configured for translating the plunger within the cavity. The plunger is not translatable during a first condition in which a coating of debris is disposed on the housing as the alloy transitions between the first and second states to define a first stress on the actuator. The plunger is translatable during a second condition in which the housing is substantially free from the coating as the alloy transitions to define a second stress on the actuator that is less than the first stress. The alloy transitions from the first to the second state at a first transformation temperature during the first condition, and at a second transformation temperature that is less than the first temperature during the second condition.

Abstract: A system for and method of reducing the effects of preheat period variation in shape memory alloy actuation, include sensing the removal of motion delay due to slack, backlash, and/or compliance in the actuator and drive-train of the system, and determining actuator activation, as a result thereof.

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: 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: 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: A lockable or latchable device includes first and second members proximate to each other, at least one of which is movable with respect to the other. The device also includes a magnetorheological fluid disposed in the device such that the fluid is in simultaneous contact with at least a portion of each of the first and second members when the first and second members are in a position for locking or latching. A permanent magnet is disposed in the device to inhibit displacement of the magnetorheological fluid when the first and second members are in the locked or latched position. An electromagnet is disposed in the device such that magnetic flux from the electromagnet, when activated, disrupts the magnetic flux of the permanent magnet when the first and second members are in the locked or latched position to unlatch or unlock the device.

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 method of manufacturing a load cell assembly and methods of folding a circuit device are disclosed. A flexible circuit body including a strip having at least one hinge is provided, with the strip being in a first position or an unfolded position. A plurality of strain gauges are attached to the strip, with the hinge disposed between the strain gauges. A jig is provided and the strip of the flexible circuit body is folded along the hinge utilizing the jig to define a second position or folded position of the strip.

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: 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 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: A system for and method of reducing the effects of preheat period variation in shape memory alloy actuation, include sensing the removal of motion delay due to slack, backlash, and/or compliance in the actuator and drive-train of the system, and determining actuator activation, as a result thereof.

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 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: Systems for and methods of determining at least one mid-stroke position of an active material actuated load by causing a stress induced rapid change in electrical resistance within the active material element, or modifying an ancillary circuit, when the load is at the mid-stroke position(s).

Abstract: An actuator includes a thermally activated active material member, and an external element configured to selectively engage the member and presenting a predetermined rate of thermal conductivity configured to transfer heat energy to and/or from the member, so as to reduce the actuation period or rate of cooling after actuation, when engaged.

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.