Provided are a volume change compensation device capable of reducing a manufacturing burden with a simple configuration and a damper device including the volume change compensation device. A damper device 100 includes a rotary damper, and includes a volume change compensation device 140 in a shaft 121 of a rotor 120. The volume change compensation device 140 includes an inner cylinder piston 142 pressed by an inner cylinder piston pressing elastic body 145 in a body tube 141 communicating with a hydraulic fluid housing portion 103 of the damper device 100 through a connection path 141a. The inner cylinder piston 142 is formed in a bottomed cylindrical shape opening on a connection path 141a side. In the inner cylinder piston 142, an inner cylinder inner small piston 143 is pressed against a bottom portion 142b by a small piston pressing elastic body 144. An air hole 142c is formed at the bottom portion 142b of the inner cylinder piston 142. The inner cylinder inner small piston 143 slides in the inner cylinder piston 142 according to the amount of hydraulic fluid 150 in the inner cylinder piston 142.

A magnetic liquid damping shock absorber includes a housing, a thermal insulating material layer, a mass block and a magnetic liquid. The housing defines a sealed cavity, the sealed cavity has a first wall face and a second wall face opposite in a first direction and a circumferential wall face located between the first wall face and the second wall face in the first direction. The thermal insulating material layer is provided on an outer surface of the housing, on a wall face of the sealed cavity or in a housing wall of the housing. The mass block is located in the sealed cavity, and the mass block and the housing define a magnetic liquid cavity therebetween. The magnetic liquid is filled in the magnetic liquid cavity.

A method of attenuating annular pressure buildup within a wellbore. The method includes accessing a wellbore, with the wellbore having an annulus disposed between first and second strings of casing. The method also includes placing a column of cement around the second string of casing generally below the first string of casing. The method further includes pumping a fluid mixture into the annulus, forming a fluid column. The fluid mixture comprises a carrier fluid, and a plurality of compressible particles dispersed in the carrier fluid. Each of the compressible particles is fabricated to partially collapse in response to thermal expansion of the fluid mixture. The method also includes placing a wellhead over the wellbore, thereby forming a trapped annulus in the wellbore. The method additionally includes at least partially sealing the annular region along at least one depth above the column of cement to inhibit vertical migration of the compressible particles.

A temperature compensating shock strut health indicator system for use with a shock strut comprises a visual indicator comprising a plurality of sectors and a pointer configured to rotate with respect to the visual indicator to point to one of the plurality of sectors. The sector to which the pointer points to is dependent on the shock strut stroke (i.e., the position of the piston with respect to the cylinder). In various embodiments, the visual indicator includes various rings that correspond to a different temperature compensated ideal stroke whereby a crew member can correspond the pointer to the appropriate ring depending on ambient temperature. In various embodiments, the pointer comprises a temperature sensitive material configured to cause the pointer to rotate with respect to the visual indicator to actively compensate for temperature.

An epicyclic gearbox is configured to transfer rotational motion between a first rotating component and a second rotating component of the gas turbine engine. The gearbox includes a centrally located sun gear, two or more planet gears circumscribing the sun gear, and a ring gear circumscribing the plurality of planet gears. The gearbox is configured such that the sun gear is drivingly coupled to the first rotating component, such that rotation of the sun gear causes rotation of each planet gear, and such that the ring gear rotates relative to the plurality of planet gears. The gearbox includes one or more shape memory alloy dampers provided in association with the sun gear, the ring gear, and/or the plurality of planet gears. The shape memory alloy damper(s) is configured in order to reduce vibrations transferred through the epicyclic gearbox to the frame, the first rotating component, and/or the second rotating component.

A crossbar assembly for facilitating isolation of a sensor assembly from vibration of a payload mounting system on a vehicle comprises an outer crossbar segment, an inner crossbar segment, and an isolator. The outer crossbar segment comprises a payload mount interface operable to mount to a payload mount, and an outer isolator interface operable to mount to an isolator. The inner crossbar segment comprises a structure interface to mount to a structure, and an inner isolator interface operable to mount to the isolator. The isolator can be supported by the outer and inner crossbar segments. The isolator comprises an elastomeric component operable to elastically deform in response to relative movement between the outer and inner crossbar segments. The isolator operates to partially decouple the outer crossbar segment from the inner crossbar segment and dampen vibrations propagating between the outer and inner crossbar segments.

A centrifugal pendulum for damping rotational irregularities of a driveshaft of an internal combustion engine, having a carrier flange element connectable indirectly or directly to the driveshaft, and having multiple pendulum elements displaceable in relation to the carrier flange element, and guided via rollers in pendulum paths. Each pendulum element is displaceable in relation to the carrier flange element in the circumferential direction between a first and a second stop position. At least one friction element having defined thermal expansion properties, which are different in particular from the carrier flange element and/or the pendulum elements, is associated with the carrier flange element, and is designed and arranged in such a way that in a defined temperature range of the centrifugal pendulum, upon a movement of at least one pendulum element corresponding to the friction element in the direction of a stop position.

A shock absorber includes a housing and an end wall slidably disposed within the housing. The end wall and the housing cooperate to define at least a portion of a cavity within the housing. The cavity is filled with a fluid, and a piston is slidably disposed within the cavity. Movement of the piston within the cavity compresses the fluid to provide a spring force. The shock absorber further includes a compensator coupled to the end wall. The compensator positions the end wall within the housing to change a volume of the cavity in response to a change in a temperature of a first element of the compensator.

A shock absorber includes a housing and an end wall slidably disposed within the housing. The end wall and the housing cooperate to define at least a portion of a cavity within the housing. The cavity is filled with a fluid, and a piston is slidably disposed within the cavity. Movement of the piston within the cavity compresses the fluid to provide a spring force. The shock absorber further includes a compensator coupled to the end wall. The compensator positions the end wall within the housing to change a volume of the cavity in response to a change in a temperature of a first element of the compensator.

A magnetic liquid damping shock absorber includes a housing, a thermal insulating material layer, a mass block and a magnetic liquid. The housing defines a sealed cavity, the sealed cavity has a first wall face and a second wall face opposite in a first direction and a circumferential wall face located between the first wall face and the second wall face in the first direction. The thermal insulating material layer is provided on an outer surface of the housing, on a wall face of the sealed cavity or in a housing wall of the housing. The mass block is located in the sealed cavity, and the mass block and the housing define a magnetic liquid cavity therebetween. The magnetic liquid is filled in the magnetic liquid cavity.