Optimal Automated Fracture Risk Assessment of 3D Gas Turbine Engine Components

2016 ◽  
Author(s):  
Michael P. Enright ◽  
Jonathan P. Moody ◽  
James C. Sobotka
Keyword(s):  
Risk Assessment ◽  
Finite Elements ◽  
Fracture Risk ◽  
Gas Turbine ◽  
High Energy ◽  
Gas Turbine Engine ◽  
Fracture Risk Assessment ◽  
Turbine Engine ◽  
Engine Components ◽  
2D And 3D

High-energy rotating components of gas turbine engines may contain rare material anomalies that can lead to uncontained engine failures. A zone-based risk assessment approach can be used to estimate component fracture risk based on groupings of finite elements (FEs) called zones. Creating zones manually is time consuming and requires human judgment. Algorithms have been developed to automatically create zones based on individual FEs, but the associated computation times increase exponentially with the number of FEs. 3D FE models typically contain millions of finite elements. Computation of component risk using individual FE-based automated zoning algorithms may take days or even weeks to complete. An improved optimal autozoning methodology has been developed that substantially reduces the computation time associated with fracture risk assessments. It combines finite elements with similar properties (i.e., stress, temperature, proximity to the surface) into groups called “pre-zones”. An automated zone creation algorithm is applied to pre-zones rather than individual FEs, reducing the overall number of computations. In this paper, the optimal autozoning methodology is presented and illustrated for FE geometries in both 2D and 3D gas turbine engine components. Based on the demonstration problem results, it is shown that the computation speed associated with the optimal autozoning algorithm is expected to be three to four orders of magnitude faster than a previous algorithm that created zones at individual FEs. The pre-zoning-based algorithm also requires less memory than previous algorithms, enabling it to solve much larger models. The resulting algorithm provides a feasible and realistic solution for fracture risk assessment of 2D and 3D component finite element models.

An Optimal Automated Zone Allocation Approach for Risk Assessment of Gas Turbine Engine Components

2013 ◽  
Author(s):  
Jonathan P. Moody ◽  
Michael P. Enright ◽  
Wuwei Liang
Keyword(s):  
Risk Assessment ◽  
Finite Element ◽  
Finite Elements ◽  
Fracture Risk ◽  
Gas Turbine ◽  
Optimal Allocation ◽  
Federal Aviation Administration ◽  
High Energy ◽  
Gas Turbine Engine ◽  
Turbine Engine

High-energy rotating components of gas turbine engines may contain rare material anomalies that can lead to uncontained engine failures. The Federal Aviation Administration and the aircraft engine industry have been developing enhanced life management methods to address the rare but significant threats posed by these anomalies. One of the outcomes of this effort has been a zone-based risk assessment methodology in which component fracture risk is estimated using groupings of elements called zones that are associated with 2D finite element (FE) stress and temperature models. Previous papers have presented processes for creation of zones either manually or via an automatic algorithm in which zones are assigned to each finite element in a component model. These processes may require significant human time and computer time. The focus of this paper is on the optimal allocation of multiple finite elements to zones that minimizes the total number of zones required to compute the fracture risk of a component. An algorithm is described that uses a relatively coarse response surface method to estimate the conditional risk value at each node in a finite element model. Zones are initially defined for each finite element in the model, and the algorithm identifies and merges zones based on minimizing the influence on component risk. The process continues until all of the zones have been merged into a single zone. The zone sequence is applied in reverse order to identify the minimum number of zones that satisfies component target risk or convergence threshold constraints. This solution provides the optimal allocation of finite elements to zones. The algorithm is demonstrated for a representative gas turbine engine component. The approach significantly improves the computational efficiency of the zone-based risk analysis process.

A Probabilistic Framework for Risk Prediction of Gas Turbine Engine Components With Inherent or Induced Material Anomalies

2005 ◽  
Author(s):  
Michael P. Enright ◽  
R. Craig McClung ◽  
Luc Huyse
Keyword(s):  
Risk Assessment ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Turbine Engines ◽  
Manufacturing Processes ◽  
Gas Turbine Engines ◽  
Probabilistic Framework ◽  
Turbine Engine ◽  
Risk Of Fracture ◽  
Engine Components

Rare anomalies may be introduced during the metallurgical or manufacturing processes that may lead to uncontained failures of aircraft gas turbine engines. The risk of fracture associated with these anomalies can be quantified using a probabilistic fracture mechanics approach. In this paper, a general probabilistic framework is presented for risk assessment of gas turbine engine components subjected to either inherent or induced material anomalies. A summary of efficient computational methods that are applicable to this problem is also provided.

Influence of Mission Variability on Fracture Risk of Gas Turbine Engine Components

2012 ◽  
Author(s):  
Michael P. Enright ◽  
Jonathan P. Moody ◽  
Ramesh Chandra ◽  
Alan C. Pentz
Keyword(s):  
Fracture Risk ◽  
Gas Turbine ◽  
Life Prediction ◽  
Damage Tolerance ◽  
Gas Turbine Engine ◽  
Fatigue Life Prediction ◽  
Turbine Engine ◽  
Risk Of Fracture ◽  
Failure Data ◽  
Engine Components

The need for application of probabilistic methods to fatigue life prediction of gas turbine engine components is being increasingly recognized by the U.S. Military. A physics-based probabilistic approach to risk assessment provides improved accuracy compared to a statistical assessment of failure data because it can be used to (1) predict future risk and (2) assess the influences of both deterministic and random variables that are not included in the failure data. Probabilistic risk and fatigue life prediction of gas turbine engine fracture critical components requires estimates of the applied stress and temperature values throughout the life of the component. These values are highly dependent upon the mission type and may vary from flight to flight within the same mission. Currently, standard missions are specified and used during the engine design process, but the associated stresses can differ significantly from stress values that are based on flight data recorder (FDR) information. For this reason, efforts are made to periodically update the standard missions and to assess the impact on component structural integrity and associated risk of fracture. In this paper, the influence of mission type and variability on fracture risk is illustrated for an actual gas turbine engine disk subjected to a number of different mission loadings. Disk stresses associated with each mission were obtained by scaling finite element model results based on RPM values obtained from engine flight recorder data. The variability in stress values throughout the life of the component was modeled using two different approaches to identify the upper and lower bound value influences on the risk of fracture. The remaining variables were based on default values provided in FAA Advisory Circular (AC) 33.14-1 “Damage Tolerance for High Energy Turbine Engine Rotors”. The risk of fracture was computed using a probabilistic damage tolerance computer code called DARWIN® (Design Assessment of Reliability With Inspection) and compared for each mission type to illustrate the maximum influence of mission type on fracture risk. The results can be used to gain insight regarding the influence of mission type and associated variability on the risk of fracture of realistic engine components.

Flexible manufacturing in repair of gas turbine engine components

1992 ◽  
Author(s):  
KIRK D ◽  
ANDREW VAVRECK ◽  
ERIC LITTLE ◽  
LESLIE JOHNSON ◽  
BRETT SAYLOR
Keyword(s):  
Gas Turbine ◽  
Flexible Manufacturing ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Engine Components

Life assessment of a high temperature probe designed for performance evaluation and health monitoring of an aero gas turbine engine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Benny George ◽  
Nagalingam Muthuveerappan
Keyword(s):  
Performance Evaluation ◽  
Gas Turbine ◽  
Health Monitoring ◽  
Gas Turbine Engine ◽  
Life Assessment ◽  
Exhaust Gas ◽  
Cycle Fatigue ◽  
Creep Life ◽  
Turbine Engine ◽  
Engine Components

AbstractTemperature probes of different designs were widely used in aero gas turbine engines for measurement of air and gas temperatures at various locations starting from inlet of fan to exhaust gas from the nozzle. Exhaust Gas Temperature (EGT) downstream of low pressure turbine is one of the key parameters in performance evaluation and digital engine control. The paper presents a holistic approach towards life assessment of a high temperature probe housing thermocouple sensors designed to measure EGT in an aero gas turbine engine. Stress and vibration analysis were carried out from mechanical integrity point of view and the same was evaluated in rig and on the engine. Application of 500 g load concept to clear the probe design was evolved. The design showed strength margin of more than 20% in terms of stress and vibratory loads. Coffin Manson criteria, Larsen Miller Parameter (LMP) were used to assess the Low Cycle Fatigue (LCF) and creep life while Goodman criteria was used to assess High Cycle Fatigue (HCF) margin. LCF and HCF are fatigue related damage from high frequency vibrations of engine components and from ground-air-ground engine cycles (zero-max-zero) respectively and both are of critical importance for ensuring structural integrity of engine components. The life estimation showed LCF life of more than 4000 mission reference cycles, infinite HCF life and well above 2000 h of creep life. This work had become an integral part of the health monitoring, performance evaluation as well as control system of the aero gas turbine engine.

Life assessment of a high temperature probe designed for performance evaluation and health monitoring of an aero gas turbine engine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Benny George ◽  
Nagalingam Muthuveerappan
Keyword(s):  
Performance Evaluation ◽  
Gas Turbine ◽  
Health Monitoring ◽  
Gas Turbine Engine ◽  
Life Assessment ◽  
Exhaust Gas ◽  
Cycle Fatigue ◽  
Creep Life ◽  
Turbine Engine ◽  
Engine Components

Abstract Temperature probes of different designs were widely used in aero gas turbine engines for measurement of air and gas temperatures at various locations starting from inlet of fan to exhaust gas from the nozzle. Exhaust Gas Temperature (EGT) downstream of low pressure turbine is one of the key parameters in performance evaluation and digital engine control. The paper presents a holistic approach towards life assessment of a high temperature probe housing thermocouple sensors designed to measure EGT in an aero gas turbine engine. Stress and vibration analysis were carried out from mechanical integrity point of view and the same was evaluated in rig and on the engine. Application of 500 g load concept to clear the probe design was evolved. The design showed strength margin of more than 20% in terms of stress and vibratory loads. Coffin Manson criteria, Larsen Miller Parameter (LMP) were used to assess the Low Cycle Fatigue (LCF) and creep life while Goodman criteria was used to assess High Cycle Fatigue (HCF) margin. LCF and HCF are fatigue related damage from high frequency vibrations of engine components and from ground-air-ground engine cycles (zero-max-zero) respectively and both are of critical importance for ensuring structural integrity of engine components. The life estimation showed LCF life of more than 4000 mission reference cycles, infinite HCF life and well above 2000 h of creep life. This work had become an integral part of the health monitoring, performance evaluation as well as control system of the aero gas turbine engine.

An Integrated Approach for Gas Turbine Engine Simulation

2000 ◽  
Author(s):  
Zhiwu Xie ◽  
Ming Su ◽  
Shilie Weng
Keyword(s):  
Gas Turbine ◽  
Local Area Network ◽  
Integrated Approach ◽  
Local Area ◽  
Gas Turbine Engine ◽  
Future Research ◽  
Area Network ◽  
Turbine Engine ◽  
Engine Simulation ◽  
Engine Components

Abstract The static and transient performance of a gas turbine engine is determined by both the characteristics of the engine components and their interactions. This paper presents a generalized simulation framework that enables the integration of different component and system simulation codes. The concept of engine simulation integration and its implementation model is described. The model is designed as an object-oriented system, in which various simulation tasks are assigned to individual software components that interact with each other. A new design rationale called “message-based modeling” and its resulting class structure is presented and analyzed. The object model is implemented within a heterogeneous network environment. To demonstrate its flexibility, the codes that deal with different engine components are separately programmed on different computers running various operating systems. These components communicate with each other via a CORBA compliant ORB, which simulates the overall performance of an engine system. The resulting system has been tested on a Local Area Network (LAN) to simulate the transient response of a three-shaft gas turbine engine, subject to small fuel step perturbations. The simulation results for various network configurations are presented. It is evident that in contrast to a standalone computer simulation, the distributed implementation requires much longer simulation time. This difference of simulation efficiency is analyzed and explained. The limitations of this endeavor, along with some future research topics, are also reported in this paper.

Ceramic Composites for Gas Turbine Engines via a New Process

1989 ◽  
Author(s):  
G. H. Schiroky ◽  
A. W. Urquhart ◽  
B. W. Sorenson
Keyword(s):  
Gas Turbine ◽  
Joint Venture ◽  
New Technology ◽  
Ceramic Composites ◽  
Gas Turbine Engine ◽  
Molten Metals ◽  
Oxidation Reactions ◽  
Turbine Engine ◽  
New Process ◽  
Engine Components

A new process for ceramic composites involves the growth of ceramic matrices through shaped preforms using directed oxidation reactions of molten metals. The preforms may consist of reinforcing fibers, whiskers, platelets, or particles, as needed to produce the desired properties in the finished component. This new technology is being developed by Lanxide Corporation and is being applied to gas turbine engine components by Du Pont Lanxide Composites Inc., a joint venture. The paper includes a description of the technology and a discussion of the status of its application to materials for gas turbine engine components.

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