Abstract: A bearing support assembly to support one or more bearings on a shaft. The bearing support assembly includes a bearing support frame configured to be coupled to a static frame, a plurality of ribs connected to the bearing support frame, and a bearing support connected to the plurality of ribs and configured to support a bearing of the one or more bearings. The bearing support assembly has a non-axisymmetric stiffness around a circumference of the bearing support assembly.

Abstract: Damping devices, turbomachines, and methods of damping vibration are provided. For example, a damping device for damping vibration of a shaft rotatable about an axis of rotation is provided. The damping device defines radial and axial directions. The damping device comprises a bearing, a housing, and a damper element. The housing and damper element define a cavity therebetween for receipt of a damping fluid. The cavity has a length along the axial direction that is curved away from the axis of rotation. As another example, a turbomachine comprising a shaft rotatable about an axis of rotation includes a damping device positioned annularly about the shaft. The damping device comprises a housing and a damper element defining a cavity therebetween for receipt of a damping fluid that has a curved shape. The cavity is curved in a plane extending along the radial and axial directions and including the axis of rotation.

Abstract: A rotor damping device for a turbomachine is provided. The rotor damping device includes a first fluid damper; and a second damper in communication with the first fluid damper, the second damper comprising a wire mesh, wherein the first fluid damper is transitionable between a working condition and an interruption condition, and wherein, during the interruption condition, the wire mesh of the second damper dampens vibration of the turbomachine.

Abstract: A turbomachine engine includes a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine also includes a shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. In one aspect, the shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). In another aspect, the shaft has a length L, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.

Abstract: A turbomachine engine including a high-pressure compressor, a high-pressure turbine, a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, and a power turbine in flow communication with the high-pressure turbine. At least one of the high-pressure compressor, the high-pressure turbine, and the power turbine comprises a ceramic matrix composite (CMC) material. The turbomachine engine includes a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft.

Abstract: A bearing support assembly to support one or more bearings on a shaft. The bearing support assembly includes a bearing support frame configured to be coupled to a static frame, a plurality of ribs connected to the bearing support frame, and a bearing support connected to the plurality of ribs and configured to support a bearing of the one or more bearings. The bearing support assembly has a non-axisymmetric stiffness around a circumference of the bearing support assembly.

Abstract: A rotor damping device for a turbomachine is provided. The rotor damping device includes a first fluid damper; and a second damper in communication with the first fluid damper, the second damper comprising a wire mesh, wherein the first fluid damper is transitionable between a working condition and an interruption condition, and wherein, during the interruption condition, the wire mesh of the second damper dampens vibration of the turbomachine.

Abstract: A turbomachine engine includes an engine core including a high-pressure compressor, a high-pressure turbine, and a combustion chamber. The engine core has a length (LCORE), and the high-pressure compressor has an exit stage diameter (DCORE). A power turbine is in flow communication with the high-pressure turbine. A low-pressure shaft is coupled to the power turbine and characterized by a midshaft rating from one hundred fifty (ft/sec)1/2 to three hundred thirty (ft/sec)1/2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second. The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft. A high-pressure shaft is coupled to the high-pressure compressor and the high-pressure turbine and is characterized by a high-speed shaft rating from 1.5 to 6.2, and a ratio of LCORE/DCORE is from 2.1 to 4.3.

Abstract: An engine for an aircraft. The engine includes a rotating airfoil assembly, at least one actuator, a torque producing system, and a controller. The rotating airfoil assembly includes a rotation axis and a plurality of rotating airfoils configured to rotate about the rotation axis in a plane of rotation. The at least one actuator is operable to change the plane of rotation of the plurality of rotating airfoils. The torque producing system is coupled to the rotating airfoil assembly and configured to rotate the rotating airfoil assembly about the rotation axis of the rotating airfoil assembly. The controller is configured to determine that the aircraft has an angle of attack and to operate the at least one actuator to change the plane of rotation of the plurality of rotating airfoils based on the angle of attack.

Abstract: 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.

Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.

Abstract: A turbomachine engine includes a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine also includes a shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. In one aspect, the shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). In another aspect, the shaft has a length L, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

Abstract: A turbomachine engine including a high-pressure compressor, a high-pressure turbine, a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, and a power turbine in flow communication with the high-pressure turbine. At least one of the high-pressure compressor, the high-pressure turbine, and the power turbine comprises a ceramic matrix composite (CMC) material. The turbomachine engine includes a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft.

Abstract: A turbomachine engine and gear assembly is provided. The engine includes a first power input component rotatable along a first direction relative to the engine centerline axis, a second power input component rotatable along a second direction relative to the engine centerline axis, a power output component rotatable relative to the engine centerline axis, a static component fixed relative to a circumferential direction relative to a gear assembly centerline axis, and a gear assembly. The gear assembly includes a first rotatable gear operably coupled to the first power input component at a first interface. The first rotatable gear is operably coupled to the static component at a static component interface. The static component interface is configured to react against the first rotatable gear to rotate the first rotatable gear relative to the gear assembly centerline axis. The power output component is operably coupled to the first rotatable gear.

Abstract: A turbomachine engine including a high-pressure compressor, a high-pressure turbine, a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, and a power turbine in flow communication with the high-pressure turbine. At least one of the high-pressure compressor, the high-pressure turbine, and the power turbine comprises a ceramic matrix composite (CMC) material. The turbomachine engine includes a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft.

Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)½ and three hundred (ft/sec)½. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.

Abstract: A turbomachine engine includes a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine also includes a shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. In one aspect, the shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). In another aspect, the shaft has a length L, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

Abstract: A turbomachine engine including an engine core including a high-pressure compressor, which has an exit stage having an exit stage diameter (DCORE), a high-pressure turbine, and a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, a power turbine in flow communication with the high-pressure turbine, and a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft. The low-pressure shaft has a length (LMSR) defined by an engine core length (LCORE) given by: LCORE=[m(20+m)*n(10+n)](1/100)*DCORE+CIS.

Abstract: A turbomachine engine includes a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine also includes a shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. In one aspect, the shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). In another aspect, the shaft has a length L, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.