scholarly journals Strain-Life Assessment of Grainex Mar-M 247 for NASA’s Turbine Seal Test Facility

2005 ◽  
Vol 127 (3) ◽  
pp. 615-620 ◽  
Author(s):  
Irebert R. Delgado ◽  
Gary R. Halford ◽  
Bruce M. Steinetz ◽  
Clare M. Rimnac
Keyword(s):  
Life Assessment ◽  
Test Facility ◽  
Mean Stress ◽  
Jet Engines ◽  
Safe Operation ◽  
Life Data ◽  
Inspection Interval ◽  
Limit Test ◽  
Bolt Holes ◽  
Test Disk

NASA’s turbine seal facility tests air-to-air seals for advanced jet engines. High temperature, speed, and pressure combinations limit test disk life, due to crack initiation in the Grainex Mar-M 247 disk bolt holes. An inspection interval is determined to ensure safe operation. Fatigue strain-life data is presented for test specimens from a test disk. Strain-life models (Manson-Hirschberg method of universal slopes, Halford-Nachtigall mean stress method, and modified Morrow method) were compared to experiment. Using experimental data at −99.95% prediction levels, accounting for six bolt holes at 0.5% total strain and 649°C, the test disk should be inspected after 665 cycles.

scholarly journals Strain-Life Assessment of Grainex Mar-M 247 for NASA’s Turbine Seal Test Facility

2004 ◽  
Author(s):  
Irebert R. Delgado ◽  
Gary R. Halford ◽  
Bruce M. Steinetz ◽  
Clare M. Rimnac
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
High Speed ◽  
Life Assessment ◽  
Current Work ◽  
Test Facility ◽  
Safe Operation ◽  
Jet Engine ◽  
Inspection Interval ◽  
Bolt Holes

NASA’s Turbine Seal Test Facility is used to test air-to-air seals for use primarily in advanced jet engine applications. Combinations of high temperature, high speed, and high pressure limit the disk life, due to the concern of crack initiation in the bolt holes of the Grainex Mar-M 247 disk. The primary purpose of this current work is to determine an inspection interval to ensure safe operation. The current work presents high temperature fatigue strain-life data for test specimens cut from an actual Grainex Mar-M 247 disk. Several different strain-life models were compared to the experimental data including the Manson-Hirschberg Method of Universal Slopes, the Halford-Nachtigall Mean Stress Method, and the Modified Morrow Method. The Halford-Nachtigall Method resulted in only an 18% difference between predicted and experimental results. Using the experimental data at a −99.95% prediction level and the presence of 6 bolt holes it was found that the disk should be inspected after 665 cycles based on a total strain of 0.5% at 649°C.

Interaction of Shroud Leakage Flow and Main Flow in a Three-Stage LP Turbine

2003 ◽  
Vol 127 (4) ◽  
pp. 649-658 ◽  
Author(s):  
Jochen Gier ◽  
Bertram Stubert ◽  
Bernard Brouillet ◽  
Laurent de Vito
Keyword(s):  
Main Flow ◽  
Secondary Flows ◽  
Test Facility ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Jet Engines ◽  
Flow Interactions ◽  
Lp Turbine ◽  
The Impact ◽  
The Ideal

Endwall losses significantly contribute to the overall losses in modern turbomachinery, especially when aerodynamic airfoil load and pressure ratios are increased. In turbines with shrouded airfoils a large portion of these losses are generated by the leakage flow across the shroud clearance. Generally the related losses can be grouped into losses of the leakage flow itself and losses caused by the interaction with the main flow in subsequent airfoil rows. In order to reduce the impact of the leakage flow and shroud design related losses a thorough understanding of the leakage losses and especially of the losses connected to enhancing secondary flows and other main flow interactions has to be understood. Therefore, a three stage LP turbine typical for jet engines is being investigated. For the three-stage test turbine 3D Navier-Stokes computations are performed simulating the turbine including the entire shroud cavity geometry in comparison with computations in the ideal flow path. Numerical results compare favorably against measurements carried out at the high altitude test facility at Stuttgart University. The differences of the simulations with and without shroud cavities are analyzed for several points of operation and a very detailed quantitative loss breakdown is presented.

Probabilistic Fatigue Assessment of a Notched Detail Taking Into Account Mean Stress Effects

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Abílio M. P. De Jesus ◽  
M. Luisa Ruiz Ripoll ◽  
Alfonso Fernández-Canteli ◽  
Enrique Castillo ◽  
Hélder F. S. G. Pereira
Keyword(s):  
Probabilistic Model ◽  
Fatigue Behavior ◽  
Material Behavior ◽  
Test Series ◽  
Model Parameters ◽  
Pressure Vessel Steel ◽  
Mean Stress ◽  
Vessel Steel ◽  
Life Data ◽  
R Ratio

Probabilistic fatigue models are required to account conveniently for the several sources of uncertainty arising in the prediction procedures, such as the scatter in material behavior. In this paper, a recently proposed stress-based probabilistic model is assessed using fatigue data available for the P355NL1 steel (a pressure vessel steel). The referred probabilistic model is a log-Gumbel regression model, able to predict the probabilistic Wöhler field (P–S–N field), taking into account the mean stress (or stress R-ratio) effects. The parameters of the probabilistic model are identified using stress-life data derived for the P355NL1 steel, from smooth specimens, for three distinct stress R-ratios, namely R = −1, R = −0.5, and R = 0. The model requires a minimum of two test series with distinct stress R-ratios. Since data from three test series is available, extrapolations are performed to test the adequacy of the model to make extrapolations for stress R-ratios other than those used in the model parameters assessment. Finally, the probabilistic model is used to model the fatigue behavior of a notched plate made of P355NL1 steel. In particular, the P–S–N field of the plate is modeled and compared with available experimental data. Cyclic elastoplastic analysis of the plate is performed since plasticity at the notch root is developed. The probabilistic model correlated appropriately the stress-life data available for the P355NL1 steel and was able to perform extrapolations for stress ratios other than those used in the model identification. The P–S–N field identified using data from smooth specimens led to consistent predictions of the P–S–N field for a notched plate, demonstrating the adequacy of the probabilistic model also to predict the probabilistic Wöhler field for notched components.

Unique Test Capabilities of the Eglin AFB McKinley Climatic Laboratory

1987 ◽  
Vol 30 (6) ◽  
pp. 27-29
Author(s):  
Lorin Klein
Keyword(s):  
Test Chamber ◽  
Test Facility ◽  
Jet Engines ◽  
Main Chamber ◽  
The World ◽  
Environmental Test

The 92,900m3 (3.28 million ft3) Main Chamber of the Climatic Laboratory (Figure 1) is the largest and most complex climatic environmental test chamber in the world. It employs an air makeup system to cool or heat air to the test temperatures and ingest this air into the chamber to allow the operation of jet engines during climatic tests. Other test chambers discussed are the 2,750 m3 (97,000 ft3) Engine and Equipment Test Facility and the 2,125 m3 (75,000 ft3) Sun, Wind, Rain, and Dust Facility.

scholarly journals Fatigue Life Estimation with Mean Stress Effect Compensation for Lightweight Structures—The Case of GLARE 2 Composite

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 251 ◽  
Author(s):  
Michał Böhm ◽  
Karolina Głowacka
Keyword(s):  
Fatigue Life ◽  
Composite Structures ◽  
Life Assessment ◽  
Stress Effect ◽  
Mean Stress ◽  
Lightweight Structures ◽  
Fatigue Life Assessment ◽  
Current State ◽  
Fatigue Life Estimation ◽  
Material Information

This paper describes the current state-of-the-art in fatigue life assessment for lightweight composite structures with the use of the frequency domain fatigue life calculation method. Random stationary gaussian loading signals have been generated and served in the process of fatigue calculation. The material information that is being used in the calculation process has been obtained from literature for the Glare 2 composite. The effect of nonzero mean stress and different fiber orientations have been taken into account. The calculations have been performed for two mean stress compensation models by Goodman and Gerber. The proposed procedure gives satisfying results for the high-cycle fatigue region for Goodman and an overall good comparison in both regimes for the Gerber model.

scholarly journals Fatigue Crack Growth Behavior Evaluation of Grainex Mar-M 247 for NASA’s High Temperature, High Speed Turbine Seal Test Rig

2007 ◽  
Author(s):  
Irebert R. Delgado ◽  
Bruce M. Steinetz ◽  
Clare M. Rimnac ◽  
John J. Lewandowski
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Depth ◽  
Growth Behavior ◽  
Operating Conditions ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Inspection Interval ◽  
Bolt Holes

The fatigue crack growth behavior of Grainex Mar-M 247 is evaluated for NASA’s Turbine Seal Test Facility. The facility is used to test air-to-air seals for use primarily in advanced jet engine applications. Because of extreme seal test conditions of temperature, pressure, and surface speeds, surface cracks may develop over time in the disk bolt holes. An inspection interval is developed to preclude catastrophic disk failure by using experimental fatigue crack growth data. By combining current fatigue crack growth results with previous fatigue strain-life experimental work an inspection interval is determined for the test disk. The fatigue crack growth life of the NASA disk bolt holes is found to be 367 cycles at a crack depth of 0.501 mm using a factor of 2 on life at maximum operating conditions. Combining this result with previous fatigue strain-life experimental work gives a total fatigue life of 1032 cycles at a crack depth of 0.501 mm. Eddy-current inspections are suggested starting at 665 cycles since eddy current thresholds are currently at 0.381 mm. Inspection intervals are recommended every 50 cycles at maximum operating conditions.

RELIABILITY ASSESSMENT FOR AN AUTOMOBILE CRANKSHAFT UNDER RANDOM LOADING

2016 ◽  
Vol 78 (6-10) ◽  
Author(s):  
S.S.K. Singh ◽  
S. Abdullah ◽  
N.A.N. Mohamed
Keyword(s):  
Fatigue Life ◽  
Structural Health Monitoring ◽  
Markov Process ◽  
Health Monitoring ◽  
Reliability Assessment ◽  
Life Assessment ◽  
Loading History ◽  
Random Loading ◽  
Structural Health ◽  
Life Data

This paper presents the stochastic process for reliability  assessment based on the fatigue life data under random loading for structural health monitoring of an automobile crankshaft due tofatigue failure. This is based on reported failure of the component due to the effect of the random loads that acts on the component during its operating condition over a given period of time. Since there are significant limitations of the experimental analysis in terms of actual loading history, therefore, the reliability assessment is considered to be less accurate. Hence, the reliability assessment based on fatigue life data using the Markov process by incorporating loading data to synthetically generate loading history has been proposed in this study. The Markov process has the capability of continuously updating the loading history data to reduce the intervals between each data point for reliability assessment based on the fatigue life data. The accuracy of the proposed monitoring system for reliability assessment was validated through its statistical method. The reliability assessment from the Markov process corresponded well by providing an accuracy of more than 95% when compared towards the actual sampling data. The reliability of the crankshaft based on the fatigue life assessment provides a highly accurate  for the improvement and control of risk factors in terms of structural health monitoring by overcoming the extensive time and cost required for fatigue testing

Service-life assessment of building components: application of evidence theory

2008 ◽  
Vol 35 (3) ◽  
pp. 287-300 ◽  
Author(s):  
A. Talon ◽  
D. Boissier ◽  
J. Lair
Keyword(s):  
Service Life ◽  
Evidence Theory ◽  
Life Assessment ◽  
Design Stage ◽  
Life Data ◽  
Performance Requirements ◽  
Short Term Exposure ◽  
Building Components ◽  
Building Component ◽  
Service Building

This paper deals with the assessment of the service life of in-service building components subjected to known environmental and usage conditions. This assessment is complex because of two primary features. First, the assessment has to be carried within a multiscale context: a geometric scale that ranges from the material or elemental to building scale; a range in the complexity of the degradation (phenomena that varies from a single phenomenon to the consideration of several degradation scenarios); a range of possible performance requirements, from one function to several; and consideration, as well, to the time over which the process is carried out that may span from the design stage to that of management and repair. Second, this assessment must also take into consideration the availability and features of service-life data that by nature is heterogeneous, imprecise, uncertain, and incomplete. In this context, a comprehensive methodology is developed using all available data on service life derived from existing methods of service-life assessment of materials, elements or building components. Such data may, for example, be extracted from fundamental studies on durability, accelerated short-term exposure tests, statistical methods, factorial methods, feedback from practice, or expert opinion or other sources. The main stages of this methodology are: (i) identification of all possible degradation scenarios provided by failure mode and effects analysis (FMEA); (ii) collection of all available service-life data (SL-data) associated with these degradation scenarios, transformation of this data into a fuzzy-set format, and assessment of its quality; (iii) processing of unification of data and aggregation of data; and (iv) assessment of the service life of building components. The case study of a window unit allows for: (i) service-life assessment of a building component to be processed by unification of data and aggregation of data and (ii) a conclusion to be deduced.

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