# US 10,872,176 B2 · Methods of making and monitoring a component with an integral strain indicator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,176 B2 - Document ID: US10872176B2 - Status: Granted - Kind: B2 - Application number: 15/412,489 - Filed: 2017-01-23 - Published: 2018-07-26 - Granted: 2020-12-22 - Earliest claimed: 2017-01-23 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Bryan Joseph Germann; Gregory Lee Hovis - Web page: https://patentgrep.com/patent/US10872176B2 ## CPC - G01B 11/16: for measuring the deformation in a solid, e.g. optical strain gauge - G01B 11/002: {for measuring two or more coordinates} - G01B 11/24: for measuring contours or curvatures - G01B 21/047: {Accessories, e.g. for positioning, for tool-setting, for measuring probes} - G06F 30/00: Computer-aided design [CAD] - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Methods of making a component with an integral strain indicator and methods of monitoring such components are provided. A method for making a component includes forming the component, the component including an internal volume and an outer surface. The method further includes forming a plurality of fiducial markers on the component, wherein each of the plurality of fiducial markers is a depression defined in the component. The plurality of fiducial markers are positioned in an analysis region of the component. ## Claims ### Claim 1 A method of making a gas turbine component with an integral strain indicator, the method comprising: forming the gas turbine component, the gas turbine component comprising an internal volume and an outer surface; and forming a plurality of fiducial markers on the gas turbine component, wherein forming the plurality of fiducial markers does not affect a grain structure of the gas turbine component, wherein each of the plurality of fiducial markers is a concave depression defined in and extending into the gas turbine component, and wherein the plurality of fiducial markers are positioned in an analysis region of the gas turbine component, the analysis region defining a gauge length, wherein the analysis region includes a life-limiting region of the gas turbine component, wherein each of the plurality of fiducial markers has a maximum diameter of between one-tenth and one-twentieth of the gauge length, wherein the step of forming the plurality of fiducial markers occurs after the step of forming the gas turbine component. ### Claim 2 (depends on 1) The method of claim 1, wherein the plurality of fiducial markers are formed on the outer surface of the gas turbine component. ### Claim 3 (depends on 1) The method of claim 1, wherein the gas turbine component comprises a base component which defines the internal volume and a thermal barrier coating deposited on the base component which defines the outer surface, and wherein the plurality of fiducial markers are formed on the base component. ### Claim 4 (depends on 1) The method of claim 1, wherein the plurality of fiducial markers comprises at least four fiducial markers in a non-linear pattern. ### Claim 5 (depends on 1) The method of claim 1, wherein each fiducial marker of the plurality of fiducial markers is a hemisphere. ### Claim 6 (depends on 1) The method of claim 1, wherein the gauge length of the analysis region is between three-tenths of an inch and one inch. ### Claim 7 (depends on 1) The method of claim 1, wherein the gauge length of the analysis region is at least twenty millimeters. ### Claim 8 (depends on 1) The method of claim 1, wherein each fiducial marker has a maximum diameter between two hundredths of an inch and twelve hundredths of an inch and a maximum depth of between one thousandth of an inch and thirty thousandths of an inch. ### Claim 9 A method of monitoring a gas turbine component, the gas turbine component comprising an internal volume and an outer surface, the method comprising: initially measuring a plurality of fiducial markers formed on the gas turbine component, wherein each of the plurality of fiducial markers is a concave depression defined in and extending into the gas turbine component, wherein the plurality of fiducial markers do not affect the grain structure of the gas turbine component, wherein the plurality of fiducial markers are positioned in an analysis region of the gas turbine component, and wherein the analysis region includes a life-limiting region of the gas turbine component; creating a three-dimensional model of the gas turbine component based on the initial measurement; subjecting the gas turbine component to at least one duty cycle; subsequently measuring the plurality of fiducial markers after the at least one duty cycle; creating a three-dimensional model of the gas turbine component based on the subsequent measurement; and comparing the three-dimensional model based on the initial measurement to the three-dimensional model based on the subsequent measurement. ### Claim 10 (depends on 9) The method of claim 9, wherein the three-dimensional model of the gas turbine component based on the initial measurement includes a representation of an initial location of each fiducial marker, the three-dimensional model of the gas turbine component based on the subsequent measurement includes a representation of a subsequent location of each fiducial marker, and the step of comparing comprises comparing the initial locations of the plurality of fiducial markers to the subsequent locations of the plurality of fiducial markers. ### Claim 11 (depends on 10) The method of claim 10, wherein the representation of the initial location of each fiducial marker comprises three-dimensional coordinates of a centroid of each fiducial marker and the representation of the subsequent location of each fiducial marker comprises three-dimensional coordinates of the centroid of each fiducial marker. ### Claim 12 (depends on 10) The method of claim 10, wherein the plurality of fiducial markers are initially and subsequently directly measured using a non-contact direct measurement technique. ### Claim 13 (depends on 9) The method of claim 9, wherein the plurality of fiducial markers are initially and subsequently directly measured using a structured light scanner comprising a structured light emitter and a detector. ### Claim 14 (depends on 13) The method of claim 13, wherein the step of initially measuring comprises projecting structured light onto the exterior surface of the gas turbine component and detecting the structured light after the structured light is reflected by the exterior surface, and the step of subsequently measuring comprises projecting structured light onto the exterior surface of the gas turbine component and detecting the structured light after the structured light is reflected by the exterior surface. ### Claim 15 (depends on 1) The method of claim 1, wherein the gas turbine component is a turbine blade.