# US 2014/0193267 A1 · DMZ Fracture Boundary Limit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0193267 A1 - Document ID: US20140193267A1 - Status: Published application - Kind: A1 - Application number: 13/738,444 - Filed: 2013-01-10 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: United Technologies Corporation - Applicants: United Technologies Corporation - Inventors: Paul D. Duesler; Paul Filewich - Web page: https://patentgrep.com/patent/US20140193267A1 ## CPC - F01D 5/12: Blades ({specially adapted for radial flow machines or engines F01D5/04}; blade roots F01D5/30; rotors with blades adjustable in operation F01D7/00; stator blades F01D9/02) - C21D 10/005: {by laser shock processing} - F01D 5/005: {Repairing methods or devices} - F01D 5/141: {Shape, i.e. outer, aerodynamic form (F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147)} - C21D 11/00: Process control or regulation for heat treatments - F05D 2260/80: Diagnostics - F05D 2260/81: Modelling or simulation - F05D 2260/94: Functionality given by mechanical stress related aspects such as low cycle fatigue [LCF] of high cycle fatigue [HCF] - Y10T 29/49231: I.C. [internal combustion] engine making - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method of establishing a boundary for a material improvement process on a workpiece is disclosed. The method may include identifying a maximum allowable damage depth on the workpiece; identifying a maximum constant thickness line on the workpiece at an extent of the maximum allowable damage depth; identifying a peak vibratory stress gradient on the workpiece; identifying a peak combined engine stress on the workpiece; and specifying the boundary for the material improvement process on the workpiece relative to the maximum constant thickness line, peak vibratory stress gradient, and peak combined engine stress. ## Claims ### Claim 1 A method of establishing a boundary for a material improvement process on a workpiece, comprising: identifying a maximum allowable damage depth on the workpiece; identifying a maximum constant thickness line on the workpiece at an extent of the maximum allowable damage depth; identifying a peak vibratory stress gradient on the workpiece; identifying a peak combined engine stress on the workpiece; and specifying the boundary for the material improvement process on the workpiece relative to the maximum constant thickness line, peak vibratory stress gradient, and peak combined engine stress. ### Claim 2 (depends on 1) The method of claim 1, further comprising checking the boundary relative to the peak combined engine stress. ### Claim 3 (depends on 1) The method of claim 1, further comprising setting the boundary for the material improvement process such that it bypasses the peak vibratory stress gradient. ### Claim 4 (depends on 1) The method of claim 1, further comprising identifying the peak combined engine stress along the maximum constant thickness line. ### Claim 5 (depends on 1) The method of claim 1, further comprising performing the material improvement process on the workpiece up to the boundary. ### Claim 6 (depends on 1) The method of claim 1, further comprising performing laser shock peening on the workpiece up to the boundary. ### Claim 7 A method of specifying a boundary for a material improvement process on an airfoil having a leading edge, a trailing edge downstream of the leading edge, a tip, and a base, the method comprising: identifying a maximum allowable damage depth from the leading edge of the airfoil; identifying a maximum constant thickness line at the maximum allowable damage depth, the constant thickness line extending from the base of the airfoil to the tip of the airfoil; identifying a peak vibratory stress gradient on the airfoil; identifying a peak combined engine stress along the maximum constant thickness line based in part on the peak vibratory stress gradient; and specifying a boundary of the material improvement process relative to the maximum allowable damage depth, maximum constant thickness line, peak vibratory stress gradient, and peak combined engine stress on the airfoil. ### Claim 8 (depends on 7) The method of claim 7, further comprising specifying the boundary does not pass through the peak vibratory stress gradient. ### Claim 9 (depends on 8) The method of claim 8, further comprising re-assessing the peak combined engine stress in relation to the boundary. ### Claim 10 (depends on 9) The method of claim 9, further comprising re-specifying the boundary if the boundary is upstream of the peak combined engine stress. ### Claim 11 (depends on 7) The method of claim 7, further comprising identifying the boundary from the tip of the airfoil to the base of the airfoil in a nonlinear configuration. ### Claim 12 (depends on 7) The method of claim 7, further comprising specifying the boundary is downstream of the maximum constant thickness line. ### Claim 13 (depends on 7) The method of claim 7, further comprising selecting an area for the material improvement process from the leading edge of the airfoil to the boundary. ### Claim 14 (depends on 13) The method of claim 13, further comprising performing the material improvement process on the selected area. ### Claim 15 (depends on 13) The method of claim 13, further comprising performing laser shock peening on the selected area. ### Claim 16 An airfoil for a gas turbine engine, comprising: a pair of opposing sides extending from a leading edge to a trailing edge and extending radially from a base to a tip; and at least one processed patch extending from the leading edge to a boundary extending from the base to the tip, the boundary positioned in relation to a maximum allowable damage depth, a maximum constant thickness line at an extent of the maximum allowable damage depth, a peak vibratory stress gradient, and a peak combined engine stress on the airfoil. ### Claim 17 (depends on 16) The airfoil of claim 16, wherein the boundary is specified downstream of the maximum allowable damage depth. ### Claim 18 (depends on 16) The airfoil of claim 16, wherein the boundary is specified downstream of the maximum constant thickness line and downstream of the peak combined engine stress. ### Claim 19 (depends on 16) The airfoil of claim 16, wherein the boundary is specified upstream of and circumventing the peak vibratory stress gradient. ### Claim 20 (depends on 16) The airfoil of claim 16, wherein the at least one processed patch is processed by laser shock peening.