Crack Propagation and Life Prediction in a Nickel-Based Superalloy under TMF Conditions

1996 ◽  
pp. 393-402 ◽  
Author(s):  
M. Arana ◽  
J. M. Martínez-Esnaola ◽  
J. Bressers
Keyword(s):  
Crack Propagation ◽  
Life Prediction ◽  
Nickel Based Superalloy

A LIFE PREDICTION MODEL OF THERMAL BARRIER COATINGS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3161-3166 ◽  
Author(s):  
LIYONG NI ◽  
CHAO LIU ◽  
CHUNGEN ZHOU
Keyword(s):  
Crack Propagation ◽  
Prediction Model ◽  
Thermal Barrier Coatings ◽  
Life Prediction ◽  
Crack Propagation Rate ◽  
Thermal Barrier ◽  
Critical Crack ◽  
Critical Crack Length ◽  
Barrier Coatings ◽  
Life Prediction Model

The durability and reliability of thermal barrier coatings(TBCs) have become a major concern of hot-section components due to lack of a reliable life prediction model. In this paper, it is found that the failure location of TBCs is at the TBC/TGO interface by a sequence of crack propagation and coalescence process. The critical crack length of failure samples is 8.8mm. The crack propagation rate is 3-10µm/cycle at the beginning and increases largely to 40µm/cycle near coating failure. A life prediction model based a simple fracture mechanics approach is proposed.

Thermo-Mechanical Fatigue of Mar-M247: Part 1—Experiments

1990 ◽  
Vol 112 (1) ◽  
pp. 68-79 ◽  
Author(s):  
D. A. Boismier ◽  
Huseyin Sehitoglu
Keyword(s):  
Grain Boundary ◽  
Prediction Model ◽  
Life Prediction ◽  
Crack Nucleation ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Boundary Crack ◽  
Mechanical Fatigue ◽  
Nickel Based Superalloy ◽  
Life Prediction Model

Isothermal fatigue tests, out-of-phase and in-phase thermo-mechanical fatigue tests were performed on Mar-M247 nickel-based superalloy. The experiments were conducted in the temperature range 500°C to 871°C. Results indicate that the lives differ with strain-temperature phasing and with strain rate. The results of out-of-phase thermo-mechanical tests correspond well with strain-life data of isothermal tests conducted at the peak temperature (871°C). However, the in-phase thermo-mechanical results differed depending on the strain amplitude. Significant surface and crack tip oxidation and gamma prime depletion has been observed based on metallographic and Auger Spectroscopic analyses. These changes were measured as a function of time. The environment induced changes significantly influenced the fatigue lives in isothermal and out-of-phase thermo-mechanical fatigue cases. In these cases transgranular cracking was observed. Grain boundary crack nucleation and grain boundary crack growth dominated the in-phase thermo-mechanical fatigue cases. Based on these observations the requirements for a life prediction model are outlined. The life prediction model and the predictions are given in Part 2 of this paper.

scholarly journals Tunnel boring machine cutterhead crack propagation life prediction with time integration method

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985345 ◽  
Author(s):  
Jianbin Li ◽  
Zhange Zhang ◽  
Zhichao Meng ◽  
Junzhou Huo ◽  
Zhaohui Xu ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Prediction Model ◽  
Crack Growth ◽  
Life Prediction ◽  
Impact Load ◽  
Time Integration ◽  
Tunnel Boring Machine ◽  
Propagation Model ◽  
Strong Impact ◽  
Tunnel Boring

Fatigue damage is one of the most common failure modes of large-scale engineering equipment, especially the full-face tunnel boring machine with characteristics of a thick plate structure bearing strong impact load. It is difficult to predict the location and propagation life of crack of cutterhead under strong impact load. Unseasonal maintenance of equipment caused by inaccurate prediction of life cycle of cutterhead seriously affects the construction efficiency of the equipment and the life safety of the operators. Determining the crack location of tunnel boring machine cutterhead structure under strong impact load and predicting the crack propagation life are difficult scientific problems. To solve them, first, the location of the stress concentration of the cutterhead is determined by using finite element analysis method of statics. Second, prediction model for crack propagation life of tunnel boring machine cutterhead characteristic substructure based on time integration is built. And the test of crack growth of cutterhead characteristic substructure is performed. The feasibility and accuracy of the prediction model are verified by contrasting crack prediction models and the results of the test. Finally, the life prediction of tunnel boring machine cutterhead of water diversion project in Northwest Liaoning Province is carried out by using crack propagation model based on time integration. Results show that the maximum error of theoretical prediction and experimental results of crack propagation is 16%. So the feasibility of crack propagation model based on time integration in predicting the crack growth of cutterhead is verified. It is predicted that the tunnel boring machine cutterhead panel can work normally for 5.9 km under the condition of ultimate load. Building the crack propagation model considering the influence of plate thickness and strong impact load has important research value for improving the working efficiency of engineering equipment, prolonging service time, and improving the working safety.

scholarly journals Fatigue Life Prediction Modeling for Turbine Hot Section Materials

1989 ◽  
Vol 111 (2) ◽  
pp. 279-285 ◽  
Author(s):  
G. R. Halford ◽  
T. G. Meyer ◽  
R. S. Nelson ◽  
D. M. Nissley ◽  
G. A. Swanson
Keyword(s):  
High Temperature ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Single Crystal ◽  
Life Prediction ◽  
Fatigue Crack Initiation ◽  
Prediction Method ◽  
Nasa Lewis Research ◽  
Prediction Modeling ◽  
Cyclic Damage

This paper presents a summary of the life prediction methods developed under the NASA Lewis Research Center’s Hot Section Technology (HOST) program. A major objective of the fatigue and fracture efforts under the HOST program was to significantly improve the analytic life prediction tools used by the aeronautical gas turbine engine industry. This has been achieved in the areas of high-temperature thermal and mechanical fatigue of bare and coated high-temperature superalloys. Such technical improvements will eventually reduce life cycle costs. The cyclic crack initiation and propagation resistance of nominally isotropic polycrystalline alloys and highly anisotropic single crystal alloys have been addressed. A sizeable data base has been generated for three alloys [cast PWA 1455 (B–1900 + Hf), wrought Inconel 718, and cast single-crystal PWA 1480] in bare and coated conditions. Two coating systems, diffusion aluminide (PWA 273) and plasma-sprayed MCrAlY overlay (PWA 286), were employed. Life prediction modeling efforts were devoted to creep-fatigue interaction, oxidation, coatings interactions, multiaxially of stress-strain states, mean stress effects, cumulative damage, and thermomechanical fatigue. The fatigue crack initiation life models developed to date include the Cyclic Damage Accumulation (CDA) Model of Pratt & Whitney and the Total Strain Version of Strainrange Partitioning (TS-SRP) of NASA Lewis for nominally isotropic materials, and the Tensile Hysteretic Energy Model of Pratt & Whitney for anisotropic superalloys. The fatigue model being developed by the General Electric Company is based upon the concepts of Path-Independent Integrals (PII) for describing cyclic crack growth under complex non-linear response at the crack tip due to thermomechanical loading conditions. A micromechanistic oxidation crack extension model has been derived by researchers at Syracuse University. The models are described and discussed in the paper. Only limited verification has been achieved to date as several of the technical programs are still in progress and the verification tasks are scheduled, quite naturally, near the conclusion of the program. To date, efforts have concentrated on developement of independent models for cyclic constitutive behavior, cyclic crack initiation, and cyclic crack propagation. The transition between crack initiation and crack propagation has not been thoroughly researched as yet, and the integration of these models into a unified life prediction method has not been addressed.

Thermomechanical fatigue behavior and life prediction of a cast nickel-based superalloy

2006 ◽  
Vol 432 (1-2) ◽  
pp. 308-316 ◽  
Author(s):  
Z.W. Huang ◽  
Z.G. Wang ◽  
S.J. Zhu ◽  
F.H. Yuan ◽  
F.G. Wang
Keyword(s):  
Life Prediction ◽  
Fatigue Behavior ◽  
Thermomechanical Fatigue ◽  
Nickel Based Superalloy

Research on the Fatigue Assessment Method for Steel Pressure Vessels Containing Surface Defects

2014 ◽  
Vol 628 ◽  
pp. 137-141
Author(s):  
Xian Lei Meng
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Life Prediction ◽  
Safety Assessment ◽  
Surface Defects ◽  
Great Influence ◽  
Assessment Method ◽  
Pressure Vessels ◽  
Test Results ◽  
Fatigue Assessment

Defects have great influence on the safe running of pressure vessels, and the safty assessment for in-service pressure vessels containing defects can realize safe and economical operation of presure vessles.Aiming at the fatigue assement of defect in steel pressure vessels,the fatigue assement method is studied and a primary program can be uesd to calculate fatigue crack propagation and life prediction is programed based on GB19624.The comparison between test and calculated results indicates that the method provided is suitable for fatigue assessment of defects.Combining the test results and cricical conditonds, the presient approach can provide a basis for the fatigue safety assessment and the reasonable overhaul cycle of in-service pressure vessels.

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