Abstract: A plurality of reversible active composite materials are disclosed, including composites based on a shape memory alloy member (SMA) and a shape memory polymer member (SMP), as well as composites based on two different SMP members. Each different member (SMA or SMP) will be trained to remember a specific shape at a specific temperature. Where two different SMP members are employed, the members exhibit different glass transition temperatures. Such composite materials can be implemented in many form factors, including two generally planar members, a single generally planar SMP member with SMA fibers distributed throughout the SMP, and a SMA fiber/wire coated with a SMP coating. In particular, the SMA fiber/wire coated with a SMP layer can be used to form helical coils that can be used in paired hinges to achieve reversible bending of a structure into which such paired hinges are incorporated.

Abstract: Linear actuators (also known as inchworm actuators) including a magnetically actuatable member with a plurality of wings or blades made from a shape memory alloy (SMA) are described. The linear actuators include a bar and an actuator assembly, configured to achieve a linear displacement of the actuator assembly relative to the bar. The actuator assembly includes a housing, a magnetic trigger including an electromagnet and a permanent magnet, and the magnetically actuatable SMA member. Significantly, the wings/blades of the magnetically actuatable SMA member are coupled to the housing. Activation of the magnetic trigger causes the magnetically actuatable SMA member to move toward the magnetic trigger. The motion of the magnetically actuatable SMA can be converted to a linear displacement. The magnetically actuatable SMA can be implemented using a SMA exhibiting both ferromagnetic and SMA properties, or by a ferromagnetic mass coupled with a SMA (i.e., a ferromagnetic SMA composite).

Abstract: Linear actuators (also known as an inchworm actuator) including a magnetically actuatable shape memory alloy (SMA) are described. The linear actuators include a bar and an actuator assembly, configured to achieve a linear displacement of the actuator assembly relative to the bar. A hybrid magnetic trigger including an electromagnet and a permanent magnet is used to selectively attract the magnetically actuatable SMA toward the magnetic trigger. The motion of the magnetically actuatable SMA can be converted to a linear displacement. The magnetically actuatable SMA can be implemented using a SMA exhibiting both ferromagnetic and SMA properties, or by a ferromagnetic mass coupled with an SMA (i.e., a ferromagnetic SMA composite). Linear actuators including bars incorporating a ratchet mechanism, and featureless bars are described. A hydraulic system incorporating actuators including magnetically actuatable SMA membranes is also disclosed.

Abstract: A membrane actuator includes a magnetically actuatable membrane and a magnetic trigger. The membrane includes a shape memory alloy (SMA), and the magnetic trigger is configured to induce a martensitic transformation in the SMA, to produce a larger force than would be achievable with non-SMA-based materials. Such a membrane actuator can be beneficially incorporated into a wide variety of devices, including fluid pumps, shock absorbing systems, and synthetic jet producing devices for use in an aircraft. The membrane/diaphragm can be formed from a ferromagnetic SMA, or a ferromagnetic material can be coupled with an SMA such that the SMA and the ferromagnetic material move together. A hybrid magnetic trigger, including a permanent magnet and an electromagnet, is preferably used for the magnetic trigger, as hybrid magnetic triggers are easy to control, and produce larger magnetic gradients than permanent magnets or electromagnets alone.

Abstract: Linear actuators (also known as inchworm actuators) including a magnetically actuatable member with a plurality of wings or blades made from a shape memory alloy (SMA) are described. The linear actuators include a bar and an actuator assembly, configured to achieve a linear displacement of the actuator assembly relative to the bar. The actuator assembly includes a housing, a magnetic trigger including an electromagnet and a permanent magnet, and the magnetically actuatable SMA member. Significantly, the wings/blades of the magnetically actuatable SMA member are coupled to the housing. Activation of the magnetic trigger causes the magnetically actuatable SMA member to move toward the magnetic trigger. The motion of the magnetically actuatable SMA can be converted to a linear displacement. The magnetically actuatable SMA can be implemented using a SMA exhibiting both ferromagnetic and SMA properties, or by a ferromagnetic mass coupled with a SMA (i.e., a ferromagnetic SMA composite).

Abstract: A membrane actuator includes a magnetically actuatable membrane and a magnetic trigger. The membrane includes a shape memory alloy (SMA), and the magnetic trigger is configured to induce a martensitic transformation in the SMA, to produce a larger force than would be achievable with non-SMA-based materials. Such a membrane actuator can be beneficially incorporated into a wide variety of devices, including fluid pumps, shock absorbing systems, and synthetic jet producing devices for use in an aircraft. The membrane/diaphragm can be formed from a ferromagnetic SMA, or a ferromagnetic material can be coupled with an SMA such that the SMA and the ferromagnetic material move together. A hybrid magnetic trigger, including a permanent magnet and an electromagnet, is preferably used for the magnetic trigger, as hybrid magnetic triggers are easy to control, and produce larger magnetic gradients than permanent magnets or electromagnets alone.

Abstract: Linear actuators (also known as an inchworm actuator) including a magnetically actuatable shape memory alloy (SMA) are described. The linear actuators include a bar and an actuator assembly, configured to achieve a linear displacement of the actuator assembly relative to the bar. A hybrid magnetic trigger including an electromagnet and a permanent magnet is used to selectively attract the magnetically actuatable SMA toward the magnetic trigger. The motion of the magnetically actuatable SMA can be converted to a linear displacement. The magnetically actuatable SMA can be implemented using a SMA exhibiting both ferromagnetic and SMA properties, or by a ferromagnetic mass coupled with an SMA (i.e., a ferromagnetic SMA composite). Linear actuators including bars incorporating a ratchet mechanism, and featureless bars are described. A hydraulic system incorporating actuators including magnetically actuatable SMA membranes is also disclosed.

Abstract: A membrane actuator includes a magnetically actuatable membrane and a magnetic trigger. The membrane includes a shape memory alloy (SMA), and the magnetic trigger is configured to induce a martensitic transformation in the SMA, to produce a larger force than would be achievable with non-SMA-based materials. Such a membrane actuator can be beneficially incorporated into a wide variety of devices, including fluid pumps, shock absorbing systems, and synthetic jet producing devices for use in an aircraft. The membrane/diaphragm can be formed from a ferromagnetic SMA, or a ferromagnetic material can be coupled with an SMA such that the SMA and the ferromagnetic material move together. A hybrid magnetic trigger, including a permanent magnet and an electromagnet, is preferably used for the magnetic trigger, as hybrid magnetic triggers are easy to control, and produce larger magnetic gradients than permanent magnets or electromagnets alone.