scholarly journals Fatigue Crack Growth Resistance of Advanced Blade Materials

1986 ◽  
Author(s):  
D. A. Wilson ◽  
D. P. Deluca ◽  
B. A. Cowles ◽  
M. A. Stucke
Keyword(s):  
Crack Growth ◽  
Turbine Blades ◽  
Weight Ratio ◽  
Engine Performance ◽  
Advanced Materials ◽  
Effect Of Temperature ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Resistance ◽  
Jet Engine ◽  
Measure Of Performance

The best measure of performance in a jet engine is the thrust-to-weight ratio. Cast single-crystal superalloys provide higher temperature capability and offer opportunities for significant improvements in future jet engine performance and durability. The highly anistropic behavior of these advanced materials, which includes modulus, strength, and ductility variation with crystallographic orientation, pose potentially significant problems for design and life prediction of advanced turbine blades. The objective of this paper is to provide a better understanding of the crack growth behavior in this advanced turbine blade material by evaluating the effect of temperature, frequency, orientation, and thickness.

Fatigue Crack Growth Resistance of Advanced Blade Materials

1987 ◽  
Vol 109 (2) ◽  
pp. 176-181 ◽  
Author(s):  
D. A. Wilson ◽  
D. P. Deluca ◽  
B. A. Cowles ◽  
M. A. Stucke
Keyword(s):  
Crack Growth ◽  
Turbine Blades ◽  
Weight Ratio ◽  
Engine Performance ◽  
Advanced Materials ◽  
Effect Of Temperature ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Resistance ◽  
Jet Engine ◽  
Measure Of Performance

The best measure of performance in a jet engine is the thrust-to-weight ratio. Cast single-crystal superalloys provide higher temperature capability and offer opportunities for significant improvements in future jet engine performance and durability. The highly anisotropic behavior of these advanced materials, which includes modulus, strength, and ductility variation with crystallographic orientation, pose potentially significant problems for design and life prediction of advanced turbine blades. The objective of this paper is to provide a better understanding of the crack growth behavior in this advanced turbine blade material by evaluating the effect of temperature, frequency, orientation, and thickness.

Effect of Temperature on Fatigue Crack Growth in CPVC

2003 ◽  
Vol 125 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Muhammad Irfan-ul-Haq ◽  
Nesar Merah
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Intensity Factor ◽  
Crack Growth ◽  
Effect Of Temperature ◽  
Stress Intensity Factor Range ◽  
Crack Growth Behavior ◽  
Different Temperatures

This study addresses the effect of temperature on fatigue crack growth (FCG) behavior of CPVC. FCG tests were conducted on CPVC SEN tensile specimens in the temperature range −10 to 70°C. These specimens were prepared from 4-in. injection-molded pipe fittings. Crack growth behavior was studied using LEFM concepts. The stress intensity factor was modified to include the crack closure and plastic zone effects. The effective stress intensity factor range ΔKeff gave satisfactory correlation of crack growth rate (da/dN) at all temperatures of interest. The crack growth resistance was found to decrease with temperature increase. The effect of temperature on da/dN was investigated by considering the variation of mechanical properties with temperature. Master curves were developed by normalizing ΔKeff by fracture strain and yield stress. All the da/dN-ΔK curves at different temperatures were collapsed on a single curve. Crazing was found to be the dominant fatigue mechanism, especially at high temperature, while shear yielding was the dominant mechanism at low temperatures.

Quantitative Evaluation of Alitize Coating on ŽS6K Ni-Base Superalloy

2014 ◽  
Vol 782 ◽  
pp. 578-583 ◽  
Author(s):  
Juraj Belan
Keyword(s):  
Turbine Blades ◽  
Advanced Materials ◽  
Diffusion Annealing ◽  
Jet Engines ◽  
Unique Combination ◽  
Jet Engine ◽  
Working Temperature ◽  
Aerospace Applications ◽  
Mechanical And Physical Properties ◽  
Base Superalloy

The aerospace industry is one of the biggest consumers of advanced materials because of its unique combination of mechanical and physical properties and chemical stability. Highly alloyed stainless steel, titanium alloys and nickel based superalloys are mostly used for aerospace applications. The aim of the work is to evaluate protective Al Si coating applied by diffusion annealing on substrate, Ni base superalloy ZS6K. This superalloy is used for turbine blade production in aero jet engine DV 2. Using of protective alitize coating provides an increasing of heat resistance of superalloy surface and increases working temperature up to 800°C. However, overcrossing of working temperature range (for ZS6K turbine blades it is from 705°C to 750°C) sometimes happen and that is the reason for detailed study of protective coating degradation. The alitize coating were evaluated in starting stage and after various time of regular loading in real aero jet engines DV 2. Coating and its degradation was evaluated with help of quantitative metallography methods (metallography software NIS Elements) and colour contrast as well.

Near-Threshold Fatigue Crack Growth Behavior of ECAPed Ultrafine-Grained Copper

2021 ◽  
Vol 1016 ◽  
pp. 1193-1198
Author(s):  
Shou Dao Qu ◽  
Ze Sheng You
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Threshold ◽  
Coarse Grained ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Resistance ◽  
Ultrafine Grained ◽  
Stress Ratios ◽  
Near Threshold

Fatigue crack growth resistance of ultrafine grained Cu processed by equal channel angular pressing (ECAP) was investigated. Particular emphasis was devoted to the effects of microstructure evolution on fatigue crack growth in the near-threshold regime. The ultrafine grained Cu exhibits a lower fatigue threshold than coarse-grained Cu at stress ratios of 0.1 and 0.7. Fatigue induced coarsening of the UFG structure near the fatigue crack and intergranular fatigue crack growth are observed.

Effect of temperature on the fatigue-crack growth behavior of the high-entropy alloy CrMnFeCoNi

2017 ◽  
Vol 88 ◽  
pp. 65-72 ◽  
Author(s):  
Keli V.S. Thurston ◽  
Bernd Gludovatz ◽  
Anton Hohenwarter ◽  
Guillaume Laplanche ◽  
Easo P. George ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Behavior ◽  
Effect Of Temperature ◽  
Crack Growth Behavior ◽  
High Entropy Alloy ◽  
Fatigue Crack Growth Behavior ◽  
High Entropy

Model Based Control Concepts for Jet Engines

2001 ◽  
Author(s):  
Klaus Lietzau ◽  
Andreas Kreiner
Keyword(s):  
Turbine Blades ◽  
Engine Performance ◽  
Current Control ◽  
Engine Control ◽  
Jet Engines ◽  
Jet Engine ◽  
Engine Model ◽  
Model Based ◽  
Safety Margins ◽  
Engine Life

Many jet engine variables cannot be measured in-flight or can only be measured with a complex, and hence unreliable, instrumentation system. This includes variables that are of imminent importance for the safe operation of the engine or for engine life, such as the temperature of the high pressure turbine blades or the surge margins of the turbo compressors, for instance. Current control systems therefore transform limits on these variables into limits on other variables measured by the engine’s sensors. This leads to increased safety margins and thus to non-optimal engine performance. An onboard engine model incorporated into the engine control system could provide information about all engine variables. This could enable further control and monitoring system optimisations leading to improved engine performance, reduced fuel consumption, increased safety and engine life. This paper explains the principle of model based engine control and gives an overview about possible applications for conventional and also thrust vectored jet engines. Modeling methods for real-time simulation as well as methods for online model adaptation are presented. The potential of model based jet engine control is analyzed and fortified by some prototype realizations.

Microstructural Effects On Fatigue-Crack Growth Behavior In γ-TiAl/β-TiNb Intermetallic Composites

1992 ◽  
Vol 273 ◽  
Author(s):  
K. T. Venkateswara Rao ◽  
R. O. Ritchie
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Strong Dependence ◽  
Crack Growth Behavior ◽  
Crack Plane ◽  
Ductile Phase ◽  
Fatigue Crack Growth Resistance ◽  
Propagation Behavior ◽  
Microstructural Effects

ABSTRACTCyclic crack-propagation behavior is examined in a series of γ-TiAl intermetallic alloys reinforced with pancake-shaped, ductile β-TiNb particles as a function of microstructure and specimen orientation. In contrast to results under monotonic loading, TiNb reinforcements are found to be far less effective in impeding crack extension under cyclic loading due to their susceptibility to premature fatigue failure, and consequently to the diminished role of shielding from crack-bridging mechanisms. Modest improvements in fatigue-crack growth resistance are observed in TiAl/TiNb composites compared to monolithic γ-TiAl, provided the particle faces are oriented perpendicular to the crack plane; however, properties are compromised in orientations where the particle edges are stacked normal to the crack plane. Microstructural effects on cyclic crack growth are less prominent in the composites, with crack-growth rates exhibiting a strong dependence on the applied ΔK level; measured exponents for the da/dN-ΔK relationship range between 10 and 20, and are found to decrease with increasing ductile phase content, yet are independent of particle thickness.

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