摘要:
A system, in certain embodiments, includes an accumulator having a first plate with a first wire guide and a second plate with a second wire guide. The second plate is positioned at an offset from the first plate, and the second plate is moveable relative to the first plate to adjust a fluid pressure. The accumulator also includes a plurality of shape memory alloy wires extending between the first and second plates, wherein the plurality of shape memory alloy wires extend along the first and second wire guides.
摘要:
The proposed adaptive exhaust nozzle features an innovative use of the shape memory alloy (SMA) actuators for actively control of the opening area of the exhaust nozzle for jet engines. The SMA actuators remotely control the opening area of the exhaust nozzle through a set of mechanism. An important advantage of using SMA actuators is the reduction of weight of the actuator system for variable area exhaust nozzle. Another advantage is that the SMA actuator can be activated using the heat from the exhaust and eliminate the need of other energy source. A prototype has been designed and fabricated. The functionality of the proposed SMA actuated adaptive exhaust nozzle is verified in the open-loop tests.
摘要:
A system and method for detecting lubrication conditions, lubrication regimes, impingement, stick-slip, and/or surface damage allows the health of a joint to be monitored. The system and method provides in situ or in vivo real-time monitoring of dynamic and static conditions of the joint. The monitoring system may use both passive and active sensing approaches that employ strategically placed piezoelectric transducers on/in the articulating components of the joint. In some embodiments, the transducers may be Lead Zirconate Titanate (PZT) transducers. Active sensing may be used to detect lubrication regimes under static and dynamic conditions. Passive sensing may be used to characterize the joint motion and abnormities, such as impingements and surface damages.
摘要:
A system, in certain embodiments, includes an accumulator. The accumulator includes a first cylinder configured to receive a fluid within an internal volume of the first cylinder. The accumulator also includes a piston configured to move axially within the first cylinder. Axial movement of the piston within the first cylinder adjusts the internal volume of the first cylinder. The accumulator further includes a plurality of shape memory alloy wires configured to cause the axial movement of the piston within the first cylinder.
摘要:
A system, in certain embodiments, includes an accumulator having a first plate, a second plate positioned at an offset from the first plate, and a shape memory alloy wire extending between the first and second plates from a first wire portion to a second wire portion. The shape memory alloy wire is configured to move the first or second plate to adjust a fluid pressure in response to an electrical current through the shape memory alloy wire. The accumulator also includes a wire clamp assembly coupled to the first wire portion and/or the second wire portion of the shape memory alloy wire.
摘要:
A system, in certain embodiments, includes a power supply. The power supply includes an ultracapacitor configured to be charged by a DC source. The power supply also includes a first switch that enables charging of the ultracapacitor by the DC source when in a closed position and disables charging of the ultracapacitor when in an open position. The power supply further includes a second switch configured to enable discharging of the ultracapacitor when in a closed position and to disable discharging of the ultracapacitor when in an open position. As the ultracapacitor is discharged, a current is supplied to actuate a shape memory alloy element.
摘要:
Electric, self-heating concrete systems that uses embedded carbon macrofiber or nanofibers paper as electric resistance heating elements are disclose. The self-heating concrete systems may utilize the conductive properties of carbon macrofiber or nanofiber materials to heat a surface overlay of concrete with various admixtures to improve the concrete's thermal conductivity. The self-heating concrete systems allow concrete roadways or the like to be heated to above freezing temperatures in a freezing environment in a reasonable amount of time.
摘要:
A system for monitoring the health of a structure, e.g., a concrete wall, bridge, pillars, using a smart aggregate is disclosed. The smart aggregate includes a piezoceramic transducer(s) and associated communication links. The transducer is embedded into the structure prior to the manufacture of the structure. The disclosed system can monitor internal stresses, cracks and other physical forces in the structures during the structures' life. The system is capable of providing an early indication of the health of the structure before a failure of the structure can occur.
摘要:
A system, in certain embodiments, includes an accumulator having a first plate with a first plurality of holes and a second plate with a second plurality of holes. The second plate is positioned at an offset from the first plate, and the second plate is moveable relative to the first plate to adjust a fluid pressure. The accumulator also includes a plurality of shape memory alloy wires extending between the first and second plates, wherein the plurality of shape memory alloy wires extend through the first and second plurality of holes.
摘要:
A carbon nanofiber aggregate (CNFA) system and method provides self-sensing capabilities that can be used to detect strain, moisture, and temperature changes. The CNFA may include cement, aggregate, silica fume, high-range water reducer (HRWR), and/or carbon nanofibers. The metal meshes in the CNFA may be utilized to monitor the electric properties of the CNFA to detect strain, moisture, and temperature changes. The CNFA may be embedded in concrete structures to allow detection of strain, moisture, and temperature changes that may cause damage to structures. Several metal meshes may be embedded in the CNFA.