# US 2019/0170607 A1 · Dual-criterion diagram methods for designing and assessing the life and strength of high-temperature rotating components > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170607 A1 - Document ID: US20190170607A1 - Status: Published application - Kind: A1 - Application number: 16/236,399 - Filed: 2018-12-29 - Published: 2019-06-06 - Earliest claimed: 2017-03-21 - Assignees: East China University of Science and Technology - Applicants: East China University of Science and Technology - Inventors: Fuzhen Xuan - Web page: https://patentgrep.com/patent/US20190170607A1 ## CPC - G01M 5/0041: {by determining deflection or stress} - G01M 15/00: Testing of engines - G01M 99/002: {Thermal testing (flaw detection G01N25/72)} - G01M 99/007: {by applying a load, e.g. for resistance or wear testing (G01M99/001 takes precedence; testing the elasticity of structures G01M5/00)} - G01N 25/00: Investigating or analyzing materials by the use of thermal means (G01N3/00 - G01N23/00 take precedence) - G06F 11/008: {Reliability or availability analysis} - G06F 30/17: Mechanical parametric or variational design - G01N 2203/0071: Creep - G01N 2203/0073: Fatigue - G01N 2203/0226: High temperature; Heating means - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract The disclosure relates to a dual-criterion diagram for designing and assessing the life and strength of high-temperature rotating components and its establishment. In addition, the disclosure relates to a method for designing and assessing the life and strength of high-temperature rotating components based on the dual-criterion diagram for designing and assessing the life and strength of high-temperature rotating components. The advantages of the disclosure include a simple design and assessment process, high operability, and reliable assessment results. The invention is expected to be applied finally to assessment and evaluation of high-cycle fatigue life of rotating components at high temperatures. ## Claims ### Claim 1 A method for establishing a dual-criterion diagram for designing and assessing the life and strength of a high-temperature rotating component comprising a material, the method comprising the following steps: S1, conducting high-temperature fatigue and creep tests using the high-temperature rotating component material, wherein the high-temperature fatigue test is conducted using an electromagnetic resonance high-frequency testing machine including a heating device and operated in a stress control mode within a frequency range of 50-250 Hz (inclusive) and the high-temperature creep test is conducted using a lever type mechanical creep testing machine including a heating device and operated in a stress control mode; S2, obtaining fatigue strengths of the material for a given life from fatigue data generated by the high-temperature fatigue test at stress ratios of R=−1 and R=0, wherein a data scattering factor is taken into account by giving a safety factor when the fatigue data are converted into design data; S3, obtaining creep rupture strength data of the high-temperature rotating component material for a given life from results of the creep test; S4, plotting a fatigue portion of the dual-criterion diagram for designing and assessing the life and strength of the high-temperature rotating components from the fatigue data of the high-temperature rotating component material obtained in step S2, so as to obtain a straight line with an abscissa axis representing the mean stress and an ordinate axis representing the stress amplitude; and S5, plotting a creep portion of the dual-criterion diagram for designing and assessing the life and strength of the high-temperature rotating component from the creep rupture strength data of the high-temperature rotating component material obtained in step S3, wherein the creep portion is a cutoff line of the straight line in step S4, and a straight line perpendicular to the abscissa axis representing mean stress. ### Claim 2 (depends on 1) The method of claim 1, wherein in step S2, in the case that an S-N curve of the material is known, the fatigue strength of the material for a given life is obtained by interpolating or extrapolating the S-N curve. ### Claim 3 (depends on 1) The method of claim 1, wherein step S4 comprises plotting the fatigue data corresponding to a designed life at stress ratios of R=−1 and R=0 obtained in step S2, with the abscissa axis representing the mean stress and the ordinate axis representing the stress amplitude, and wherein the fatigue portion in step S4 is represented by the following Equation (1): σ a = σ 0 - σ - 1 σ 0  σ m + σ - 1 ( 1 ) where σm, is mean stress; σa is stress amplitude; σ−1 represents a fatigue strength at R=−1 for a designed life; and σ0 represents a fatigue strength at R=0 for the designed life. ### Claim 4 (depends on 1) The method of claim 1, wherein the creep portion in step S5 is represented by the following Equation (2): σm=σ(t, T) (2) where σm is mean stress; σ(t, T) is a creep rupture strength at a service temperature for a designed life; t represents the service time; T represents the service temperature; wherein Equation (2) indicates that the mean stress at this time is equivalent to the creep rupture strength for the designed life. ### Claim 5 (depends on 1) A method for designing and assessing the life and strength of the high-temperature rotating component using the dual-criterion diagram established according to the method of claim 1 comprising: S6, conducting stress analysis of the high-temperature rotating component utilizing finite element analysis and a structural model, based on material performance parameters and service parameters of the high-temperature rotating component to obtain mean stress and stress amplitude of the high-temperature rotating component at alternating loads, and to determine a critical section and critical point of the high-temperature rotating component under service conditions; S7, plotting the mean stress and the stress amplitude of the high-temperature rotating component at the critical section and the critical point into the dual-criterion diagram, wherein the high-temperature rotating component is safe in a designed life if a point having a horizontal coordinate representing mean stress and a vertical coordinate representing stress amplitude fall in the safe region. ### Claim 6 (depends on 5) The method of claim 5, wherein in step S6, determining the critical section and the critical point of the high-temperature rotating component under service conditions includes determining a high mean stress region and a high stress amplitude region of the high-temperature rotating component. ### Claim 7 (depends on 5) The method of claim 5, wherein in step S6, the performance parameters of the rotating component material include linear expansion coefficient α, elastic modulus E, Poisson ratio μ and material density ρ, and the service parameters of the high-temperature rotating component include rotating speed, thermal boundary and displacement boundary. ### Claim 8 (depends on 5) The method of claim 5, wherein in step S6, the performance parameters and the service parameters of the rotating component material are obtained by at least one of: (A) searching a database of material performances; and (B) conducting corresponding tests. ### Claim 9 (depends on 5) The method of claim 5, wherein in step S7, if a point having a horizontal coordinate representing mean stress and a vertical coordinate representing stress amplitude does not fall in the safe region, a design scheme is modified by returning to step S6 and repeating the analysis.