A New Modified Contrast Method for Life Prediction in Combined Cycle Fatigue Test

2017 ◽  
Author(s):  
Lei Han ◽  
Cao Chen ◽  
Xiaoyong Zhang ◽  
Xiaojun Yan
Keyword(s):  
Turbine Blade ◽  
High Cycle Fatigue ◽  
Aerodynamic Force ◽  
Low Cycle Fatigue ◽  
Fracture Morphology ◽  
Combined Cycle ◽  
Full Scale ◽  
Cycle Fatigue ◽  
Contrast Method ◽  
Ultra High Cycle Fatigue

The combined high and low cycle fatigue (CCF) test on full scale turbine blade in the laboratory is an important method to evaluate the life. In fact, the low cycle fatigue which is usually caused by the centrifugal force can be confirmed easily. While, the high cycle fatigue which is usually caused by the vibration and aerodynamic force is often hard to determine. So the previous scholar has proposed the contrast method to determine the high cycle load in the field. This method utilizes the new and used blades to determine the high cycle within certain limits. While it can’t be applied effectively in the whole life range with the low cycle-high cycle-ultra high cycle fatigue theory raised. So this paper put forward the modified contrast method to realize the optimization. Firstly, the CCF tests are carried out on the turbine blade systematically. Then, the CCF damage properties, including the crack propagation, the fracture morphology and the dynamic characteristic are analyzed. Lastly, the new modified contrast method is proposed with the new coordinate axes, new fitting criterions and amend method. Through comparisons we conclude that: the new method is slightly complicated, but the evaluate precision has significantly increased. So it could be used to deal with data for CCF tests on full scale turbine blade in the future.

scholarly journals Untersuchungskonzept zum Einfluss hoher Dehnraten auf die Zahnfußtragfähigkeit

2021 ◽  
Author(s):  
Moritz Trippe ◽  
Johannes Lövenich ◽  
Oscar Malinowski ◽  
Christian Brecher ◽  
Jens Brimmers ◽  
...  
Keyword(s):  
High Cycle Fatigue ◽  
Cycle Fatigue ◽  
Ultra High Cycle Fatigue

ZusammenfassungDer Einsatz von Getrieben in elektrifizierten Antriebssträngen und Flugzeugturbinen führt zu höheren Betriebsdrehzahlen und einer höheren Anzahl von Lastwechseln. Lastwechselzahlen von N > 107 im Ultra High Cycle Fatigue (UHCF) Bereich bewirken eine Abnahme der Dauerfestigkeit von Einsatzstählen. Außerdem steigt mit zunehmender Drehzahl die Dehnrate im Zahnfuß, was ebenfalls einen Einfluss auf die Dauerfestigkeit hat. Aufgrund der geringen Drehzahlen konventioneller Verspannungsprüfstände ist eine Untersuchung der Dehnrateneffekte heute nicht möglich. Darüber hinaus ist die Untersuchung des UHCF-Bereichs wegen der langen Prüfzeiten unwirtschaftlich.Ziel des Berichts ist ein Prüfstandskonzept zur Untersuchung des Einflusses höherer Dehnraten auf die Zahnfußtragfähigkeit von Zahnrädern bei hohen Drehzahlen. Zunächst werden die Leistungsanforderungen an das neue Prüfstandskonzept abgeleitet. Basierend auf diesen Anforderungen wird das Prüfgetriebe unter Verwendung der Norm ISO 6336 ausgelegt. Die Auslegung wird mit einer FE-basierten Zahnkontaktanalyse verifiziert und die erreichbaren Dehnraten im Betrieb analysiert. Abschließend wird das Prüfstandskonzept hinsichtlich der Lastaufbringung, des Lagerkonzepts, des Schmierungskonzepts und der möglichen Schadenserkennung vorgestellt. Der Prüfstand bietet die Möglichkeit, höhere Dehnraten zu untersuchen. Zusätzlich kann der UHCF-Bereich von Getrieben effizienter untersucht werden.

Component Low Cycle Fatigue Behavior Based on Standard Calculation Procedure and Non-Linear FEA

2017 ◽  
Author(s):  
Jürgen Rudolph ◽  
Adrian Willuweit ◽  
Steffen Bergholz ◽  
Christian Philippek ◽  
Jevgenij Kobzarev
Keyword(s):  
Power Plants ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Hybrid Approach ◽  
Combined Cycle ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Constitutive Material Model ◽  
Standard Design ◽  
Creep Fatigue

Components of conventional power plants are subject to potential damage mechanisms such as creep, fatigue and their combination. These mechanisms have to be considered in the mechanical design process. Against this general background — as an example — the paper focusses on the low cycle fatigue behavior of a main steam shut off valve. The first design check based on standard design rules and linear Finite Element Analysis (FEA) identifies fatigue sensitive locations and potentially high fatigue usage. This will often occur in the context of flexible operational modes of combined cycle power plants which are a characteristic of the current demands of energy supply. In such a case a margin analysis constitutes a logical second step. It may comprise the identification of a more realistic description of the real operational loads and load-time histories and a refinement of the (creep-) fatigue assessment methods. This constitutes the basis of an advanced component design and assessment. In this work, nonlinear FEA is applied based on a nonlinear kinematic constitutive material model, in order to simulate the thermo-mechanical behavior of the high-Cr steel component mentioned above. The required material parameters are identified based on data of the accessible reference literature and data from an own test series. The accompanying testing campaign was successfully concluded by a series of uniaxial thermo-mechanical fatigue (TMF) tests simulating the most critical load case of the component. This detailed and hybrid approach proved to be appropriate for ensuring the required lifetime period of the component.

On the critical inclusion size of high strength steels under ultra-high cycle fatigue

2006 ◽  
Vol 427 (1-2) ◽  
pp. 167-174 ◽  
Author(s):  
Z.G. Yang ◽  
J.M. Zhang ◽  
S.X. Li ◽  
G.Y. Li ◽  
Q.Y. Wang ◽  
...  
Keyword(s):  
High Cycle Fatigue ◽  
High Strength Steels ◽  
High Strength ◽  
Inclusion Size ◽  
Cycle Fatigue ◽  
Ultra High Cycle Fatigue

High and Low Cycle Fatigue of Orthorhombic Ti-22Al-27Nb Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 589-594
Author(s):  
Masuo Hagiwara ◽  
A. Araoka ◽  
Satoshi Emura
Keyword(s):  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Lamellar Microstructure ◽  
Control Mode ◽  
Load Control ◽  
Cycle Fatigue ◽  
Lamellar Morphology ◽  
R Ratio ◽  
Fatigue Mechanism

The effect of the lamellar morphology on the high cycle fatigue (HCF) and low cycle fatigue (LCF) behavior of the Ti-22Al-27Nb alloy was investigated. The HCF tests were performed in air at an R ratio of 0.1 in the load-control mode, whereas the LCF tests were performed in vacuum at 923 K in the strain-controlled mode. The specimens with fine lamellar microstructure exhibited a better resistance to HCF than those with coarse lamellar microstructure. The microstructure-insensitive behavior was, however, observed in the LCF tests at 923 K. The fatigue mechanism was discussed based on the concurrent observation of the initiation facet and the underlying microstructure, and the TEM observations.

Effect of Plasma Nitriding on Ultra-High Cycle Fatigue Behaviors of Ti-6Al-4V

2011 ◽  
Vol 295-297 ◽  
pp. 2386-2389 ◽  
Author(s):  
Ren Hui Tian ◽  
Qiao Lin Ouyang ◽  
Qing Yuan Wang
Keyword(s):  
High Cycle Fatigue ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Ultra High Cycle Fatigue ◽  
Stress Ratios

In order to investigate the effect of plasma nitriding treatment on fatigue behavior of titanium alloys, very high cycle fatigue tests were carried out for Ti-6Al-4V alloy using an ultrasonic fatigue machine under load control conditions for stress ratios of R=-1 at frequency of ƒ=20KHz. Experiment results showed that plasma nitriding treatment played the principal role in the internal fatigue crack initiation. More importantly, plasma nitriding treatment had a detrimental effect on fatigue properties of the investigated Ti-6Al-4V alloy, and the fatigue strength of material after plasma nitriding treatment appeared to be significantly reduced about 17% over the untreated material.

scholarly journals Current understanding of ultra-high cycle fatigue

2012 ◽  
Vol 2 (3) ◽  
pp. 031002 ◽  
Author(s):  
Qingyuan Wang ◽  
Muhammad Kashif Khan ◽  
Claude Bathias
Keyword(s):  
High Cycle Fatigue ◽  
Current Understanding ◽  
Cycle Fatigue ◽  
Ultra High Cycle Fatigue
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