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 gas turbine engine including a rotating shaft and a bearing assembly. The bearing assembly is configured to support the rotating shaft. The bearing assembly has a first bearing and a second bearing. The first bearing is configured to support an axial load of the rotating shaft when a forward thrust of the rotating shaft is greater than ten percent. The second bearing is configured to support the axial load of the rotating shaft when a thrust of the rotating shaft is between ten percent forward thrust and ten percent aft thrust, inclusive of the end points.

Abstract: A gas turbine engine including a rotating shaft and a bearing assembly. The bearing assembly is configured to support the rotating shaft. The bearing assembly has a first bearing and a second bearing. The first bearing is configured to support an axial load of the rotating shaft when a forward thrust of the rotating shaft is greater than ten percent. The second bearing is configured to support the axial load of the rotating shaft when a thrust of the rotating shaft is between ten percent forward thrust and ten percent aft thrust, inclusive of the end points.

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 damping device that includes features for damping bending vibration of a shaft rotating about its axis of rotation and methods for damping bending vibration utilizing the damping device are provided. In one exemplary aspect, the damping device includes a damping disc operatively coupled with a shaft, e.g., of a turbine engine or shaft system. The damping disc is at least partially received within a chamber defined by a housing. The chamber of the housing is configured to receive a damping fluid. When the shaft is rotated about its axis of rotation, the damping disc is movable within the chamber to move the damping fluid such that the damping fluid absorbs bending vibration emitted by the shaft. The damping fluid moved by the damping disc dampens bending vibration emitted by the shaft.

Abstract: A gas turbine engine includes a compressor rotor shaft assembly, an accessory gearbox, and a bowed-rotor mitigation drive device drivingly coupled with the accessory gearbox. The bowed-rotor mitigation drive device is driven during an engine startup phase so as to induce a mechanical load (mechanical energy) to the bowed-rotor mitigation drive device. The mechanical load (mechanical energy) is retained within the bowed-rotor mitigation drive device during operation of the gas turbine engine. The mechanical load (mechanical energy) retained within the bowed-rotor mitigation drive device is periodically released by the bowed-rotor mitigation drive device in a plurality of periods so as to provide, in each period, a driving force to the accessory gearbox, which provides the driving force to the compressor rotor shaft assembly to periodically rotate the compressor rotor shaft assembly.

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 gas turbine engine includes a compressor rotor shaft assembly, an accessory gearbox, and a bowed-rotor mitigation drive device drivingly coupled with the accessory gearbox. The bowed-rotor mitigation drive device is driven during an engine startup phase so as to induce a mechanical load (mechanical energy) to the bowed-rotor mitigation drive device. The mechanical load (mechanical energy) is retained within the bowed-rotor mitigation drive device during operation of the gas turbine engine. The mechanical load (mechanical energy) retained within the bowed-rotor mitigation drive device is periodically released by the bowed-rotor mitigation drive device in a plurality of periods so as to provide, in each period, a driving force to the accessory gearbox, which provides the driving force to the compressor rotor shaft assembly to periodically rotate the compressor rotor shaft assembly.

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 lubricant supply system for a squeeze film damper. The lubricant supply system includes a fluid passage configured to supply a lubricant to the squeeze film damper of a bearing assembly. The fluid passage includes a first flow path for lubricant into the lubricant supply system and into the squeeze film damper of the bearing assembly and a second flow path for lubricant into the squeeze film damper of the bearing assembly. The lubricant supply system includes a valve assembly configured to allow the fluid passage to move from the first flow path to the second flow path in response to an interruption of the first flow path.

Abstract: A bearing system is configured to surround a rotor along a circumferential direction corresponding to the rotor. The rotor is extended along an axial direction co-directional to a centerline axis of the rotor. The bearing system includes a body from which a plurality of first support members is each extended, and wherein the plurality of first support members is spaced apart from one another along the circumferential direction. Each first support member includes a first axial support arm extended along the axial direction and a first radial support arm extended from the first axial support arm along a radial direction. The first radial support arm is configured to position a bearing element in contact with a bearing surface at the rotor.

Abstract: A power transmission system includes a shaft, a stator disposed within the shaft and substantially concentric with the shaft; and at least one supporting element positioned between the stator and the shaft and configured to support the shaft on the stator to reduce a vibration of the shaft and allow the shaft to rotate relative to the stator. A gas turbine engine including the power transmission system is also described.

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 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 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 casing for a bearing of a gas turbine engine includes a shaft extending along an axial direction. The casing includes an attachment feature at a radially outermost portion of the casing. The attachment feature is configured to be coupled to a static frame of the gas turbine engine. The casing further includes a plurality of support arms extend from the attachment feature to a radially innermost portion of the casing. At least one support arm of the plurality of support arms defines an internal cavity. Further, the radially innermost portion of the casing is configured to be coupled to an outer race of the bearing. The casing additionally includes a reinforcing member housed at least partially within the internal cavity of at least one support arm. Moreover, the reinforcing member includes a shape memory alloy material.

Abstract: A gas turbine engine including a first rotor assembly comprising a first drive shaft extended along a longitudinal direction; a housing coupled to the first rotor assembly to provide rotation of the first rotor assembly around an axial centerline; a first accessory assembly, wherein the first accessory assembly sends and/or extracts energy to and from the first rotor assembly; and a first clutch assembly disposed between the first rotor assembly and the first accessory assembly. The first clutch assembly engages and disengages the first rotor assembly to and from the first accessory assembly.