摘要:
A device and method for controlling a phase transformation temperature of a shape memory alloy is provided. The device includes a primary wire composed of the shape memory alloy. The primary wire defines first and second ends, the first end being attached to a fixed structure and the second end being able to displace. An activation source is thermally coupled to the wire and is operable to selectively cause the primary wire to reversibly transform from a Martensitic phase to an Austenitic phase during a cycle. A loading element is operatively connected to the primary wire and configured to selectively increase a tensile load on the primary wire when an ambient temperature is at or above a threshold temperature, thereby increasing the phase transformation temperature of the primary wire.
摘要:
A device and method for controlling a phase transformation temperature of a shape memory alloy is provided. The device includes a primary wire composed of the shape memory alloy. The primary wire defines first and second ends, the first end being attached to a fixed structure and the second end being able to displace. An activation source is thermally coupled to the wire and is operable to selectively cause the primary wire to reversibly transform from a Martensitic phase to an Austenitic phase during a cycle. A loading element is operatively connected to the primary wire and configured to selectively increase a tensile load on the primary wire when an ambient temperature is at or above a threshold temperature, thereby increasing the phase transformation temperature of the primary wire.
摘要:
A drain plug assembly that has particular application for sealing a drain hole in a high voltage battery compartment on a vehicle. The plug assembly includes a plug that inserted into the drain hole. The plug assembly further includes a return spring coupled to the plug and causing the plug to be biased into the drain hole. The plug assembly also includes at least one shape memory alloy device coupled to the plug and a support structure. The SMA device receives an electrical current that causes the device to contract and move the plug out of the drain hole against the bias of the return spring.
摘要:
A system for and method of providing overload protection for an active material actuator, includes a magnetically functioning mechanism comprising, for example, one or more permanent or electromagnets, and/or magnetorheological fluid, and configured to produce a holding force less than the capacity of the actuator, and more preferably, a modifiable holding force responsive to load influencing conditions.
摘要:
A method of starting a heat engine includes exposing an element of the heat engine to a source of thermal energy provided by a temperature difference between a heat source having a first temperature and a heat sink having a second temperature that is lower than the first temperature. The element is 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 the heat sink. The method further includes changing the crystallographic phase of the first shape memory alloy to thereby convert thermal energy to mechanical energy, and inducing initial movement of the element in a desired operational direction to thereby start the heat engine.
摘要:
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.
摘要:
A drain plug assembly that has particular application for sealing a drain hole in a high voltage battery compartment on a vehicle. The plug assembly includes a plug that inserted into the drain hole. The plug assembly further includes a return spring coupled to the plug and causing the plug to be biased into the drain hole. The plug assembly also includes at least one shape memory alloy device coupled to the plug and a support structure. The SMA device receives an electrical current that causes the device to contract and move the plug out of the drain hole against the bias of the return spring.
摘要:
A heat transport system includes a fluid, a heat engine, and a component. The fluid has a first fluid region at a first temperature and a second fluid region at a second temperature that is different from the first temperature. The heat engine includes a shape-memory alloy disposed in contact with each of the first fluid region and the second fluid region. The heat engine is operable to transfer heat from one of the first fluid region and the second fluid region to the other of the first fluid region and the second fluid region in response to the crystallographic phase of the shape-memory alloy.
摘要:
A method of starting a heat engine includes exposing an element of the heat engine to a source of thermal energy provided by a temperature difference between a heat source having a first temperature and a heat sink having a second temperature that is lower than the first temperature. The element is 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 the heat sink. The method further includes changing the crystallographic phase of the first shape memory alloy to thereby convert thermal energy to mechanical energy, and inducing initial movement of the element in a desired operational direction to thereby start the heat engine.
摘要:
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.