# US 2019/0170068 A1 · Shaft shear detection for gas turbine engines > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170068 A1 - Document ID: US20190170068A1 - Status: Published application - Kind: A1 - Application number: 15/829,145 - Filed: 2017-12-01 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Pratt & Whitney Canada Corp. - Applicants: Pratt & Whitney Canada Corp. - Inventors: Michael DARBY; Reza PEDRAMI - Web page: https://patentgrep.com/patent/US20190170068A1 ## CPC - F01D 17/04: responsive to load - F02C 9/28: Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed (F02C9/30 - F02C9/38, F02C9/44 take precedence) - F01D 21/04: responsive to undesired position of rotor relative to stator {or to breaking-off of a part of the rotor}, e.g. indicating such position - F01D 21/045: {special arrangements in stators or in rotors dealing with breaking-off of part of rotor} - F01D 21/06: Shutting-down - G01B 21/32: for measuring the deformation in a solid - F02D 35/02: on interior conditions - F05D 2260/80: Diagnostics - F16C 3/02: Shafts; Axles - F16C 2233/00: Monitoring condition, e.g. temperature, load, vibration - F16C 2360/23: Gas turbine engines - G01B 7/16: for measuring the deformation in a solid, e.g. by resistance strain gauge - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A system and a method for detecting a shaft shear event in a gas turbine engine are disclosed. The system comprises a sensor configured to detect a shaft shear force exerted by a shaft on a support structure supporting the shaft where the shaft shear force is indicative of shearing of the shaft. The system also comprises a controller operatively coupled to the sensor and configured to initiate a shutdown of the gas turbine engine in response to the detection of the shaft shear force by the sensor. ## Claims ### Claim 1 A system for detecting a shaft shear event in a gas turbine engine having a turbine supported by a shaft, the system comprising: a sensor configured and located to detect a shaft shear force exerted by the shaft on a support structure of the engine, the shaft shear force being indicative of shearing of the shaft; and a controller operatively coupled to the sensor and configured to initiate a shutdown of the gas turbine engine in response to the detection of the shaft shear force by the sensor. ### Claim 2 (depends on 1) The system of claim 1, wherein the shaft shear force comprises a predetermined change in axial force exerted by the shaft of the gas turbine engine on the support structure as a function of time. ### Claim 3 (depends on 2) The system of claim 2, wherein the predetermined change in force comprises a 50% increase in the axial force exerted by the shaft of the gas turbine engine on the support structure in a predetermined period of time. ### Claim 4 (depends on 1) The system of claim 1, wherein the sensor comprises a load cell disposed in a load path between the shaft of the gas turbine engine and the support structure. ### Claim 5 (depends on 1) The system of claim 1, wherein the sensor comprises a load cell disposed in a load path between a thrust bearing supporting the shaft of the gas turbine engine and the support structure. ### Claim 6 (depends on 1) The system of claim 1, wherein the sensor comprises a strain gauge configured to detect a strain of the support structure in response to the shaft shear force exerted by the shaft of the gas turbine engine on the support structure. ### Claim 7 A gas turbine engine comprising: a shaft having a first portion in torque-transmitting engagement with a load, and a second portion in torque-transmitting engagement with a turbine; and a sensor configured and located to detect a shaft shear force exerted by the shaft on a support structure supporting the shaft, the shaft shear force being indicative of shearing of the shaft at a location axially between the first and second portions of the shaft; and a controller operatively coupled to the sensor and configured to initiate a shutdown of the gas turbine engine in response to the detection of the shaft shear force by the sensor. ### Claim 8 (depends on 7) The gas turbine engine of claim 7, wherein the shaft shear force comprises a predetermined change in axial force exerted by the shaft of the gas turbine engine on the support structure as a function of time. ### Claim 9 (depends on 8) The gas turbine engine of claim 8, wherein the predetermined change in force comprises a 50% increase in the axial force exerted by the shaft of the gas turbine engine on the support structure in a predetermined period of time. ### Claim 10 (depends on 7) The gas turbine engine of claim 7, wherein the sensor comprises a load cell disposed in a load path between the shaft of the gas turbine engine and the support structure. ### Claim 11 (depends on 7) The gas turbine engine of claim 7, wherein the sensor comprises a load cell disposed in a load path between a thrust bearing supporting the shaft of the gas turbine engine and the support structure. ### Claim 12 (depends on 7) The gas turbine engine of claim 7, wherein the sensor comprises a strain gauge configured to detect a strain of the support structure in response to the shaft shear force exerted by the shaft of the gas turbine engine on the support structure. ### Claim 13 A method for detecting a shaft shear event in a gas turbine engine, the method comprising: detecting a shaft shear force exerted by a shaft of the gas turbine engine on a support structure supporting the shaft, the shaft shear force being indicative of shearing of the shaft; and initiating a shutdown of the gas turbine engine in response to the detection of the shaft shear force. ### Claim 14 (depends on 13) The method of claim 13, wherein detecting the shaft shear force comprises detecting a predetermined change in axial force exerted by the shaft of the gas turbine engine on the support structure as a function of time. ### Claim 15 (depends on 14) The method of claim 14, wherein the predetermined change in force comprises a 50% increase in the axial force exerted by the shaft of the gas turbine engine on the support structure in a predetermined period of time. ### Claim 16 (depends on 13) The method of claim 13, comprising detecting the shaft shear force using a load cell disposed in a load path between a thrust bearing supporting the shaft of the gas turbine engine and the support structure. ### Claim 17 (depends on 13) The method of claim 13, comprising detecting the shaft shear force by detecting a strain of the support structure in response to the shaft shear force exerted by the shaft of the gas turbine engine on the support structure. ### Claim 18 A system comprising: a sensor configured and located to detect a force exerted by a shaft of a gas turbine engine on a support structure of the gas turbine engine supporting the shaft; and a controller operatively coupled to the sensor and configured to initiate a control function associated with the gas turbine engine in response to the detection of the force by the sensor. ### Claim 19 (depends on 18) The system of claim 18, wherein the force comprises an axial force exerted by the shaft of the gas turbine engine on the support structure. ### Claim 20 (depends on 18) The system of claim 18, wherein the force is indicative of an operation of a feathering system for a propeller coupled to the gas turbine engine. ### Claim 21 (depends on 18) The system of claim 18, wherein the control function comprises an adjustment of a thrust or power setting of the gas turbine engine. ### Claim 22 (depends on 18) The system of claim 18, wherein: the force comprises a change in axial force exerted by the shaft of the gas turbine engine on the support structure, the change in axial force being indicative of an occurrence of damage to a fan coupled to the shaft; and the control function comprises an adjustment of a thrust or power setting of the gas turbine engine. ### Claim 23 (depends on 18) The system of claim 18, wherein the sensor comprises a load cell disposed in a load path between the shaft of the gas turbine engine and the support structure. ### Claim 24 (depends on 18) The system of claim 18, wherein the sensor comprises a load cell disposed in a load path between a thrust bearing supporting the shaft of the gas turbine engine and the support structure. ### Claim 25 (depends on 18) The system of claim 18, wherein the sensor comprises a strain gauge configured to detect a strain of the support structure in response to the shaft shear force exerted by the shaft of the gas turbine engine on the support structure. ### Claim 26 A method comprising: detecting a force exerted by a shaft of the gas turbine engine on a support structure of the gas turbine engine supporting the shaft; and initiating a control function associated with the gas turbine engine in response to the detection of the force. ### Claim 27 (depends on 26) The method of claim 26, wherein the force comprises an axial force exerted by the shaft of the gas turbine engine on the support structure. ### Claim 28 (depends on 26) The method of claim 26, wherein the force is indicative of an operation of a feathering system for a propeller coupled to the gas turbine engine. ### Claim 29 (depends on 26) The method of claim 26, wherein the control function comprises an adjustment of a thrust or power setting of the gas turbine engine. ### Claim 30 (depends on 26) The method of claim 26, wherein: the force comprises a change in axial force exerted by the shaft of the gas turbine engine on the support structure, the change in axial force being indicative of an occurrence of damage to a fan coupled to the shaft; and the control function comprises an adjustment of a thrust or power setting of the gas turbine engine. ### Claim 31 (depends on 26) The method of claim 26, wherein the force comprises an axial force in a load path between the shaft of the gas turbine engine and the support structure. ### Claim 32 (depends on 26) The method of claim 26, wherein the force comprises an axial force in a load path between a thrust bearing supporting the shaft of the gas turbine engine and the support structure. ### Claim 33 (depends on 26) The method of claim 26, comprising detecting the force by detecting a strain of the support structure in response to the force exerted by the shaft of the gas turbine engine on the support structure.