Design and Manufacturing Strategy of a Back-to-Back Test Rig for Investigation of Ultra High Cycle Fatigue Strength Regarding Tooth Root Strength in Aerospace Applications

2020 ◽  
Author(s):  
Johannes Loevenich ◽  
Moritz Trippe ◽  
Jens Brimmers ◽  
Christian Brecher ◽  
S. Stark ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Tooth Root ◽  
Cycle Fatigue ◽  
Manufacturing Strategy ◽  
Test Rig ◽  
Aerospace Applications ◽  
Design And Manufacturing ◽  
Root Strength ◽  
Ultra High Cycle Fatigue

scholarly journals Effect of Yttrium Content on the Ultra-High Cycle Fatigue Behavior of Mg-Zn-Y-Zr Alloys

2015 ◽  
Vol 816 ◽  
pp. 333-336 ◽  
Author(s):  
D.K. Xu ◽  
E.H. Han
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Slip Bands ◽  
Long Life ◽  
Ultra High Cycle Fatigue ◽  
Hardness Values ◽  
Zr Alloys

In the super-long life regime, the fatigue behavior of as-extruded Mg-6wt%Zn-xY-0.8wt%Zr Mg alloys with Y content of 0, 1, 2 and 3 wt% have been investigated, respectively. The result indicated that for all measured S-N curves, a plateau existed in the regime of 5×106-108 cyc, and then the fatigue strength gradually decreased between 108 and 109 cycles. Therefore, only fatigue strength corresponding to 109 cycles can be determined. Compared with other alloys, the alloy with Y content of 2 wt% has the highest fatigue strength and its value is 105 MPa. SEM observations to fracture surfaces revealed that for all alloys, the fatigue crack mostly initiated at the surface or subsurface of samples failed within 106-109 cycles. Further observation indicated that the crack initiation was related with activated slip bands instead of phase particles and activated twins. Based on the measured results and Murakami equation, it demonstrates that the fatigue strength of alloys is more dependent on the hardness values.

Effect of fisheye failure on material performance inducing error circle under high cycles

2021 ◽  
pp. 105678952110200
Author(s):  
Haiyan Ge ◽  
Xintian Liu ◽  
Xu Wang ◽  
Xiaolan Wang ◽  
Haijie Wang
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Engineering Application ◽  
High Strength ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Ultra High Cycle Fatigue ◽  
Strength Models ◽  
Error Circle

In the engineering application of high strength steel and surface strengthening steel, fisheye failure is often happened in high cycle fatigue. To explore the effect of fisheye failure on high cycle fatigue properties of materials, a high cycle fatigue life model was established based on the Murakami and Tanaka’s fatigue strength models. The model introduces the error circle to evaluate fisheye size, and discusses the influencing factors of fatigue strength. The results show that the size and depth of fisheye failure will affect performance of materials. The proposed model considering the size and depth of defect quantitatively shows the influence of fisheye details on material performance, and effectively predicts the high/ultra-high cycle fatigue life.

scholarly journals On the determination of the bending fatigue strength in and above the very high cycle fatigue regime of shot-peened gears

2021 ◽  
Author(s):  
D. Fuchs ◽  
S. Schurer ◽  
T. Tobie ◽  
K. Stahl
Keyword(s):  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Load Carrying Capacity ◽  
Cycle Fatigue ◽  
Bending Fatigue ◽  
Very High Cycle Fatigue ◽  
Bending Load ◽  
Load Carrying ◽  
Bending Fatigue Strength ◽  
Very High

AbstractDemands on modern gearboxes are constantly increasing, for example to comply with lightweight design goals or new CO2 thresholds. Normally, to increase performance requires making gearboxes and powertrains more robust. However, this increases the weight of a standard gearbox. The two trends therefore seem contradictory. To satisfy both of these goals, gears in gearboxes can be shot-peened to introduce high compressive residual stresses and improve their bending fatigue strength. To determine a gear’s tooth root bending fatigue strength, experiments are conducted up to a defined number of load cycles in the high cycle fatigue range. However, investigations of shot-peened gears have revealed tooth root fracture damage initiated at non-metallic inclusions in and above the very high cycle fatigue range. This means that a further reduction in bending load carrying capacity has to be expected at higher load cycles, something which is not covered under current standard testing conditions. The question is whether there is a significant decrease in the bending load carrying capacity and, also, if pulsating tests conducted at higher load cycles—or even tests on the FZG back-to-back test rig—are necessary to determine a proper endurance fatigue limit for shot-peened gears. This paper examines these questions.

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.

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

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.

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