Abstract: Described and shown are passive variable stiffness devices, which are of compact design and configured to produce a restoring force that varies optimally with the isolator displacement when subjected to vibration-inducing loading.

Abstract: Described and shown are passive variable stiffness devices, which are of compact design and configured to produce a restoring force that varies optimally with the isolator displacement when subjected to vibration-inducing loading.

Abstract: A passive variable negative stiffness device (passive VNSD) configured to facilitate a transition to zero stiffness by using elastic devices (e.g., springs) combined with translating and rotating components. An exemplary embodiment of a passive VNSD may comprise at least one pretensioned and/or precompressed elastic device to produce the desired force-displacement profiles. For instance, an exemplary embodiment of a passive VNSD may be adapted to produce force-displacement profiles that transition from zero stiffness, to negative stiffness, and then to positive stiffness (ZNP) and from zero stiffness, to negative stiffness, and then back to zero stiffness (ZNZ).

Abstract: A resetting semi-passive stiffness damper (RSPSD) triggering assembly and a RSPSD and method of use for damping movement of an object. Exemplary embodiments of a RSPSD triggering assembly include, for example, a rotatable disc and a spring-loaded lever arranged between the disc and a slotted channel. A sensor is provided and communicates with a bypass valve on the cylinder. A change in the direction of movement of the disc causes reciprocation of the lever in the channel, which causes the sensor to send open and close signals to the bypass valve. In some embodiments, a single disc may be replaced with two interacting discs. A RSPSD equipped with such a triggering assembly is usable to damp movement of an object of interest.

Abstract: A passive variable negative stiffness device (passive VNSD) configured to facilitate a transition to zero stiffness by using elastic devices (e.g., springs) combined with translating and rotating components. An exemplary embodiment of a passive VNSD may comprise at least one pretensioned and/or precompressed elastic device to produce the desired force-displacement profiles. For instance, an exemplary embodiment of a passive VNSD may be adapted to produce force-displacement profiles that transition from zero stiffness, to negative stiffness, and then to positive stiffness (ZNP) and from zero stiffness, to negative stiffness, and then back to zero stiffness (ZNZ).

Abstract: A resetting semi-passive stiffness damper (RSPSD) triggering assembly and a RSPSD and method of use for damping movement of an object. Exemplary embodiments of a RSPSD triggering assembly include, for example, a rotatable disc and a spring-loaded lever arranged between the disc and a slotted channel. A sensor is provided and communicates with a bypass valve on the cylinder. A change in the direction of movement of the disc causes reciprocation of the lever in the channel, which causes the sensor to send open and close signals to the bypass valve. In some embodiments, a single disc may be replaced with two interacting discs. A RSPSD equipped with such a triggering assembly is usable to damp movement of an object of interest.

Abstract: A resetting semi-passive stiffness damper (RSPSD) for use in damping movement. Embodiments of such a RSPSD include, for example, a pistoned cylinder connected to a grooved rack, and a spring-loaded lever arranged between the rack and a slotted channel above the rack. One end of the lever is allowed to move pivotably and vertically within the channel as the other end moves with the rack. A sensor is provided and communicates with a bypass valve on the cylinder. A change in the direction of movement of the rack forces the lever further into the slotted channel where it eventually triggers the sensor, which then sends a signal to open the bypass valve. As the rack continues to move, the lever eventually reverses direction, and is forced back down the slotted channel by a return spring. Upon leaving the sensing range of the sensor, the valve is signaled to close.

Abstract: A resetting semi-passive stiffness damper (RSPSD) for use in damping movement. Embodiments of such a RSPSD include, for example, a pistoned cylinder connected to a grooved rack, and a spring-loaded lever arranged between the rack and a slotted channel above the rack. One end of the lever is allowed to move pivotably and vertically within the channel as the other end moves with the rack. A sensor is provided and communicates with a bypass valve on the cylinder. A change in the direction of movement of the rack forces the lever further into the slotted channel where it eventually triggers the sensor, which then sends a signal to open the bypass valve. As the rack continues to move, the lever eventually reverses direction, and is forced back down the slotted channel by a return spring. Upon leaving the sensing range of the sensor, the valve is signaled to close.