Out-of-Phase and In-Phase Thermo-Mechanical Fatigue Response Simulations of Haynes 230

2014 ◽  
Author(s):  
Raasheduddin Ahmed ◽  
Paul R. Barrett ◽  
Tasnim Hassan
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Gas Turbines ◽  
Rate Dependence ◽  
Maximum Temperature ◽  
Large Set ◽  
Mean Stress ◽  
Stress Evolution ◽  
Haynes 230 ◽  
Mechanical Fatigue

Temperatures at critical locations in propulsion turbine engine combustor components can be as high as 982°C (1800°F). High temperature thermal gradients, and start-up and shut-down operations of gas turbines, induce thermo-mechanical fatigue (TMF) failure. Dwell periods at high temperatures accompanied by repeated loading cycles, eventually lead to failure of the components through creep-fatigue processes. In an effort to decipher the complex high temperature phenomena, a large set of isothermal and thermo-mechanical fatigue experiments have been carried out on the gas turbine combustor liner material, Haynes 230. The out-of-phase strain-controlled TMF experiments with compressive peak hold result in mean stress evolution in the tensile direction, whereas the in-phase TMF experiments with tensile peak hold result in mean stress evolution in the compressive direction. Experimental results indicate that the maximum temperature in the loading cycle influences the material property evolution with cycle. A unified viscoplastic constitutive model based on the Chaboche type nonlinear kinematic hardening rule was developed, including the added features of strain range dependence, rate dependence, temperature rate dependence, static recovery, mean stress evolution, and maximum temperature influence. The new constitutive model was validated against stress-strain responses of Haynes 230 under TMF loading. Paper published with permission.

Constitutive Modeling of Haynes 230 for Anisothermal Thermo-Mechanical Fatigue and Multiaxial Creep-Ratcheting Responses

2013 ◽  
Author(s):  
Raasheduddin Ahmed ◽  
Paul R. Barrett ◽  
Tasnim Hassan
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Structural Integrity ◽  
Kinematic Hardening ◽  
Critical Evaluation ◽  
Accurate Estimation ◽  
Nickel Base Superalloy ◽  
Haynes 230 ◽  
Analysis And Design ◽  
Mechanical Fatigue

Service life analysis and design of high temperature components, such as turbine engines, needs accurate estimation of stresses and strains at failure locations. The structural integrity under these high temperature environments can be evaluated through finite element structural analysis. This requires a robust constitutive model to predict local stresses and strains. A unified viscoplastic constitutive model based on the Chaboche type nonlinear kinematic hardening rule was developed including the added features of strain range dependence, rate dependence, temperature dependence, static recovery, and a mean stress evolution. The new constitutive model was validated through critical evaluation of the simulation of a broad set of stress and strain responses of a nickel-base superalloy Haynes 230. The experimental database encompasses uniaxial strain-controlled loading histories which include isothermal low cycle creep-fatigue and anisothermal thermo-mechanical fatigue experiments at temperatures ranging from 75°F to 1800°F. Simulations from the modified model are presented to demonstrate its strengths and weaknesses, and future work is needed for developing a robust constitutive model.

Constitutive Model Development for Thermo-Mechanical Fatigue Response Simulation of Haynes 230

2012 ◽  
Author(s):  
Raasheduddin Ahmed ◽  
Mamballykalathil Menon ◽  
Tasnim Hassan
Keyword(s):  
Stress Response ◽  
Constitutive Model ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Large Set ◽  
Mean Stress ◽  
Liner Material ◽  
Mechanical Fatigue ◽  
Combustor Liner ◽  
Mean Strain

Turbine engine combustor components are subject to thermo-mechanical fatigue (TMF) during service. The combustor liner temperatures can sometimes reach as high as 1800°F. An accurate estimate of the strains at critical locations in the combustor liner is required for reliable lifing predictions. This demands the need for a detailed analysis of the TMF responses and a robust constitutive model capable of predicting the same. A large set of experiments have been carried out on the liner material, a nickel based alloy, HA 230, in an effort to understand its thermo-mechanical fatigue constitutive response. The out-of-phase strain-controlled TMF experiments with a negative mean strain show a positive mean stress response, while the in-phase TMF experiments with a positive mean strain show a negative mean stress response. A Chaboche based viscoplastic constitutive model is under development. It will have several essential features such as nonlinear kinematic hardening, isotropic hardening, strain range dependence, rate dependence, temperature dependence and static recovery. The constitutive model being developed for accurately calculating the stress-strain response is being carried out with the final objective of predicting the strains in an actual combustor liner in service through finite element simulation for fatigue lifing.

A Unified Constitutive Model for the Inelastic Uniaxial Response of Rene’ 80 at Temperatures Between 538C and 982C

1990 ◽  
Vol 112 (3) ◽  
pp. 280-286 ◽  
Author(s):  
V. G. Ramaswamy ◽  
D. C. Stouffer ◽  
J. H. Laflen
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Constitutive Equation ◽  
Constitutive Model ◽  
Mean Stress ◽  
Torsional Loading ◽  
Creep Response ◽  
Cyclic Response ◽  
Mechanical Cycling ◽  
Starting Point

The objective of this research is to develop a constitutive equation for the uniaxial monotonic and cyclic response of Rene’80 between the temperatures of 538C and 982C. The constitutive equation is accompanied by experimental data for the evaluation of the material constants. Extensive verification is achieved through the successful correlation of tensile and creep response and prediction of mechanical cycling experiments including mean stress shifts. These results also serve as a starting point for reformulating the model for the prediction of the high temperature multiaxial response of Rene’80 that includes torsion, proportional, and nonproportional uniaxial and torsional loading histories.

JESSOP SAVILLE H.40

Alloy Digest ◽  
1963 ◽  
Vol 12 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Alloy Steel ◽  
Gas Turbines ◽  
Heat Treating ◽  
Temperature Performance

Abstract Jessop-Saville H.40 is an alloy steel recommended for high-temperature stressed components of gas turbines. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-140. Producer or source: Jessop-Saville Ltd, Brightside Works.

Experimental and Numerical Investigation on the Influence of Process Speed on the Blanking Process

2002 ◽  
Vol 124 (2) ◽  
pp. 416-419 ◽  
Author(s):  
A. M. Goijaerts ◽  
L. E. Govaert ◽  
F. P. T. Baaijens
Keyword(s):  
Stainless Steel ◽  
Constitutive Model ◽  
Numerical Simulations ◽  
Ferritic Stainless Steel ◽  
Fracture Criterion ◽  
Fracture Initiation ◽  
Rate Dependence ◽  
Numerical Predictions ◽  
Punch Velocity ◽  
Blanking Process

In a previous work a numerical tool was presented which accurately predicted both process force and fracture initiation for blanking of a ferritic stainless steel in various blanking geometries. This approach was based on the finite element method, employing a rate-independent elasto-plastic constitutive model combined with a fracture criterion which accounts for the complete loading history. In the present investigation this work is extended with respect to rate-dependence by employing an elasto-viscoplastic constitutive model in combination with the previously postulated fracture criterion for ferritic stainless steel. Numerical predictions are compared to experimental data over a large range of process speeds. The rate-dependence of the process force is significant and accurately captured by the numerical simulations at speeds ranging from 0.001 to 10 mm/s. Both experiments and numerical simulations show no influence of punch velocity on fracture initiation.

An Improved Nickel Based MIMS Thermocouple for High Temperature Gas Turbine Applications

2012 ◽  
Author(s):  
Michele Scervini ◽  
Catherine Rae
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
High Temperatures ◽  
Gas Turbines ◽  
Material Science ◽  
University Of Cambridge ◽  
Type K ◽  
Metallurgical Analysis ◽  
The University ◽  
High Temperature Gas

A new Nickel based thermocouple for high temperature applications in gas turbines has been devised at the Department of Material Science and Metallurgy of the University of Cambridge. This paper describes the new features of the thermocouple, the drift tests on the first prototype and compares the behaviour of the new sensor with conventional mineral insulated metal sheathed Type K thermocouples: the new thermocouple has a significant improvement in terms of drift and temperature capabilities. Metallurgical analysis has been undertaken on selected sections of the thermocouples exposed at high temperatures which rationalises the reduced drift of the new sensor. A second prototype will be tested in follow-on research, from which further improvements in drift and temperature capabilities are expected.

A Multiscale NDT System for Damage Detection in Thermal Barrier Coatings

2009 ◽  
Author(s):  
A. M. G. Luz ◽  
D. Balint ◽  
K. Nikbin
Keyword(s):  
High Temperature ◽  
Damage Detection ◽  
Luminescence Spectrum ◽  
Bond Coat ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Assessment Tool ◽  
Diagnostic Tools ◽  
Spectral Parameters ◽  
Temperature Oxidation

Progress in aero-engines and land-based gas turbines is continuously linked with a rise of the operating temperature. TBCs are multilayered structures which function together to effectively lower the temperature of its load-bearing superalloy substrate while simultaneously providing oxidation protection against high temperature combustion environments during operation. They typically comprise of a ceramic top coat for thermal insulation and a metallic bond coat that provides oxidation/corrosion resistance and enhances the adhesion of the YSZ to the superalloy substrate. Due to high-temperature oxidation of the bond coat, a thermally grown oxide (TGO) scale of continuous Al2O3 is formed between the ceramic top coat and the bond coat. The formation and growth of the TGO increases the mismatch of thermal expansion coefficients among the multilayered TBC and induce high thermal stresses leading to spallation of the YSZ coat from the underlying metal. Hence, nondestructive diagnostic tools that could reliably probe the subsurface damage state of TBCs are essential to take full advantage of these systems. In this contribution, a new concept of multiscale NDT system is presented. The instrument uses a combination of imaging-based methods with photoluminescence piezospectroscopy, a laser-based method. Imaging-based methods like mid-infrared reflectance, laser optical backscatter and infrared tomography were used to predict the overall lifetime of the coated component. When TBCs approach the end of life, micro-crack nucleation and propagation at the top coat/bond coat interface increases the amount of reflected light. This rise in reflectance was correlated with the lifetime of the component using a neural network that merges the mean and standard deviation value of the gray level. Photoluminescence piezospectroscopy was subsequently used to give information about the structural integrity of the hot spots identified in the image analysis. This laser-based technique measures in-situ the residual stress in the TGO at room temperature. Damage leads to a relaxation of the local stress which is in turn reflected in the luminescence spectrum shape. However, presently there is no agreement on the best spectral parameters that should be used as a measure of the damage accumulation in the coatings. Therefore, the evolution of luminescence spectrum from as-manufactured to critically damaged TBCs was determined using the finite element method. This approach helped to identify the most suitable spectral parameters for damage detection, improving the reliability of photoluminescence piezospectroscopy as a failure assessment tool for TBCs.

A Method for Predicting the Behavior of Plastics at Different Temperatures

2014 ◽  
Vol 1039 ◽  
pp. 107-111
Author(s):  
Yang Chen ◽  
Gui Qin Li ◽  
Bin Ruan ◽  
Xiao Yuan ◽  
Hong Bo Li
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Constitutive Model ◽  
Research And Development ◽  
Mechanical Behavior ◽  
Plastic Material ◽  
Different Temperatures ◽  
Plastic Parts

The mechanical behavior of plastic material is dramatically sensitive to temperature. An method is proposed to predict the mechanical behavior of plastics for cars, ranging from low-temperature low temperature ≤-40°C to high temperature ≥80°C. It dominates the behavior of plastic material based on improved constitutive model in which the parameters adjusted by a series of tests under different temperatures. The method is validated with test and establishes the basis for research and development of plastic parts for automobile as well.

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