Damage Tolerance and Reliability of Turbine Engine Components
Damage Tolerance and Reliability of Turbine Engine Components

Author: Christos C. Chamis

Publisher:

Published: 1999

Total Pages: 24

ISBN-13:

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This report describes a formal method to quantify structural damage tolerance and reliability in the presence of a multitude of uncertainties in turbine engine components. The method is based at the material behavior level where primitive variables with their respective scatter ranges are used to describe behavior. Computational simulation is then used to propagate the uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from this method demonstrate that it is mature and that it can be used to probabilistically evaluate turbine engine structural components. It may be inferred from the results that the method is suitable for probabilistically prediciting the remaining life in aging or deteriorating structures, for making strategic projections and plans, and for achieving better, cheaper, faster products that give competitive advantages in world markets.

Fatigue Reliability of Gas Turbine Engine Structures
Fatigue Reliability of Gas Turbine Engine Structures

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-08

Total Pages: 58

ISBN-13: 9781722393229

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The results of an investigation are described for fatigue reliability in engine structures. The description consists of two parts. Part 1 is for method development. Part 2 is a specific case study. In Part 1, the essential concepts and practical approaches to damage tolerance design in the gas turbine industry are summarized. These have evolved over the years in response to flight safety certification requirements. The effect of Non-Destructive Evaluation (NDE) methods on these methods is also reviewed. Assessment methods based on probabilistic fracture mechanics, with regard to both crack initiation and crack growth, are outlined. Limit state modeling techniques from structural reliability theory are shown to be appropriate for application to this problem, for both individual failure mode and system-level assessment. In Part 2, the results of a case study for the high pressure turbine of a turboprop engine are described. The response surface approach is used to construct a fatigue performance function. This performance function is used with the First Order Reliability Method (FORM) to determine the probability of failure and the sensitivity of the fatigue life to the engine parameters for the first stage disk rim of the two stage turbine. A hybrid combination of regression and Monte Carlo simulation is to use incorporate time dependent random variables. System reliability is used to determine the system probability of failure, and the sensitivity of the system fatigue life to the engine parameters of the high pressure turbine. 'ne variation in the primary hot gas and secondary cooling air, the uncertainty of the complex mission loading, and the scatter in the material data are considered. Cruse, Thomas A. and Mahadevan, Sankaran and Tryon, Robert G. Glenn Research Center...

Optimum Fracture Control Plan for Gas Turbine Engine Components
Optimum Fracture Control Plan for Gas Turbine Engine Components

Author: T. Lassen

Publisher:

Published: 1994

Total Pages: 14

ISBN-13:

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This paper describes a probabilistic damage tolerance concept for the fatigue damage in gas turbine engine components. The statistical scatter in time to crack initiation is considered using a Weibull distribution, while the stochastic crack growth is treated by a Markov chain approximation. The approximation is a unit-jump discrete state/discrete time Markov chain where damage states are related to the fatigue crack depths. The model parameters are estimated from experimental statistics and a linear fracture mechanics simulation of the fatigue propagation. The effect of in-service inspection is considered by the use of Bayesian updating techniques. The analysis verifies that it is possible to extend the service life and maintain the fatigue reliability of critical components by an appropriate periodic inspection program.

The Role of Spectrum Loading in Damage-Tolerance Life-Management of Fracture Critical Turbine Engine Components
The Role of Spectrum Loading in Damage-Tolerance Life-Management of Fracture Critical Turbine Engine Components

Author: James M. Larsen

Publisher:

Published: 2003

Total Pages: 14

ISBN-13:

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Recent developments in experimental and computational capabilities suggest an opportunity to develop improved models of crack growth for use in life management of materials and components in advanced gas turbine engines. Improvements in such models have potential benefits in the sustainment of aging engines, as well as the design of more durable future engines. Current approaches for life management of engine components tend to ignore potential increases in crack propagation lifetime that may occur as the result of load interaction phenomena under variable amplitude spectrum loading. In effort to quantify these potential benefits, a study of updated mission profiles was performed. A variety of engine usage spectra were surveyed to document their cycle content statistically, including characterization of the fundamental load sequence events and the expected severity of damage produced by these events, using data from the advanced nickel-base superalloy IN100.

Materials and Strength of Gas Turbine Parts
Materials and Strength of Gas Turbine Parts

Author: Leonid Borisovich Getsov

Publisher: Springer Nature

Published: 2021-04-17

Total Pages: 469

ISBN-13: 9811605343

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This book discusses several mechanical and material problems that are typical for gas turbine components. It discusses accelerated tests and other methods for increasing the reliability of gas turbine engines. Special attention is given to non-traditional methods for calculating the strength characteristics and longevity of the main components. This first volume focuses on the selection of materials, deformation and destruction mechanisms in connection with stationary and non-stationary loading, and types of material damage such as the thermal fatigue. Particular attention is paid to the issues of the properties of single crystal alloys, the relationship between structure and properties, the influence of technological factors and long-term operation. The characteristics of creep resistance, crack resistance, and resistance to cyclic deformation of different alloys are given.

A Software Framework for Probabilistic Fatigue Life Assessment of Gas Turbine Engine Rotors
A Software Framework for Probabilistic Fatigue Life Assessment of Gas Turbine Engine Rotors

Author: HR. Millwater

Publisher:

Published: 2004

Total Pages: 17

ISBN-13:

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An enhanced life management process based on probabilistic damage tolerance methods has been developed to address material anomalies in titanium rotating components of gas turbine engines. Related methods are being used as tools to investigate the impact of engine monitoring and usage variability on prognosis for field readiness and life management. This paper begins with an overview of the process of probabilistic damage tolerant design, using the DARWIN® computer program to illustrate the interplay between various random variables and the conventional elements of structural design and life prediction. Special attention is then given to the initial distribution of material anomalies, scatter in fatigue crack growth data, and variability in complex mission histories. The significance of each source of variability for different applications is discussed.