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AssigneeFatigue Management Associates LLC
InventorStanley G. Berkley
Estimating the term…
Improved methods for managing a population of metal components subject to fatigue failure are provided. The residual compressive stress in the critical surfaces of such components, especially in areas of high stress concentration, are measured non-destructively using x-ray diffraction techniques. The measured surface residual compressive stress is used as a management criterion. A component having a surface residual compressive stress greater than a predetermined value can be returned to service. However, once the measured surface residual compressive stress of a component falls below the predetermined value, it can either be removed permanently from service, or it can be reworked to increase its surface residual compressive stress and then returned to service. Additionally, by measuring the surface residual compressive stress of an individual component, the remaining service life of that individual component can be estimated. These methods for management of populations of such metal components allow for increasing the service life of the components in a safe and effective manner. Methods are also provided for the manufacture and/or design of metal parts with improved performance criterion (e.g., reduction in weight) while maintaining acceptable service life. Methods are also provided for establishing quality control procedures using surface residual compressive stress measurements during and/or after the manufacturing process in order to prevent, for example, introduction of metal parts having insufficient surface residual compressive stress levels for their intended use.
A method for designing a fatigue-limited metal part whereby a selected performance criterion for the metal part is improved while maintaining sufficient residual compressive stress to achieve an acceptable service life for the metal part, said method comprising:
A method as defined in claim is wherein the selected performance criterion is a reduction in weight of the metal part.
A method for designing a fatigue-limited metal part whereby the weight of the metal part is reduced while maintaining sufficient residual compressive stress to achieve an acceptable service life for the metal part, said method comprising:
A method for designing a fatigue-limited metal part whereby the weight of the metal part is minimized while maintaining sufficient residual compressive stress to achieve an acceptable service life and safety factor for the metal part, said method comprising:
A quality control method for the manufacture of fatigue-limited metal components, said method comprising measuring the residual compressive stress in one or more critical surface areas for each metal component after its manufacture and before placing it into service, comparing the measured residual compressive stress in one or more critical surface areas to a corresponding predetermined residual compressive stress level for the one or more critical surfaces, and flagging each metal component which has its measured residual compressive stress below its corresponding predetermined residual compressive stress level, whereby flagged metal components are not placed in service.
Dependencies are inferred from the claim text.