A comparison between bending and diametral fatigue tests for bituminous materials

The possibility of life and reliability enhancing of AL-31F low pressure turbine disc’s fir-tree slots by ultrasonic hardening is considered. Having disc’s material properties studied, working stress derivation is executed which was further used for following comparative fatigue tests. Also, Davidenkov method residual stress analysis is carried out which showed 95.3 % change to compression stress for circumferential residual stress and 80.9 % change to compression stress for axial residual stress which proves possibility of fir-tree slots’ life and reliability enhancement by ultrasonic hardening. Comparative fatigue tests with N = 4•10 5 cycles basis showed that the hardened samples standing out the cycle basis during higher oscillatory amplitudes (and, thus, affecting loads) than the non-hardened basic ones.

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Modeling a random sequence of extremes of loads for fatigue tests under irregular loading

10.36652/0042-4633-2020-5-13-19 ◽

2020 ◽

pp. 13-19

Author(s):

N.A. Mahutov ◽

I.V. Gadolina ◽

S.G. Lebedinskiy ◽

E.S. Oganyan ◽

A.A. Bautin

Keyword(s):

Random Sequence ◽

Fatigue Tests ◽

Linear Hypothesis ◽

Resource Estimation ◽

Transition Matrices ◽

Random Loading ◽

Markov Transition ◽

Random Nature ◽

Irregular Loading ◽

Markov Transition Matrices

Methods and approaches to tests under random loading are considered, their role is characterized. To ensure the random nature of loading, a modeling method based on Markov transition matrices and real processes recorded in operation is proposed. Keywords: random loading process, Markov repetition matrices, resource estimation, corrected linear hypothesis, parameter of completeness of the loading spectrum. [email protected]

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Hawk Mk 51/51A/66 Tailplane Full-Scale Fatigue Tests

ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing - Lecture Notes in Mechanical Engineering ◽

10.1007/978-3-030-21503-3_63 ◽

2019 ◽

pp. 801-815

Author(s):

Risto Laakso ◽

Jussi Kettunen ◽

Juha Lähteenmäki

Keyword(s):

Fatigue Tests ◽

Full Scale

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Aluminide Thermal Barrier Coating for High Temperature Performance of MAR 247 Nickel Based Superalloy

Coatings ◽

10.3390/coatings11010048 ◽

2021 ◽

Vol 11 (1) ◽

pp. 48

Author(s):

Mateusz Kopec ◽

Dominik Kukla ◽

Xin Yuan ◽

Wojciech Rejmer ◽

Zbigniew L. Kowalewski ◽

...

Keyword(s):

High Temperature ◽

Stress Amplitude ◽

Aluminide Coating ◽

Chemical Vapor ◽

Fatigue Tests ◽

Protective Atmosphere ◽

X Ray ◽

Nickel Based Superalloy ◽

Barrier Coating ◽

Aluminide Layer

In this paper, mechanical properties of the as-received and aluminide layer coated MAR 247 nickel based superalloy were examined through creep and fatigue tests. The aluminide layer of 20 µm was obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of the layer was characterized using the scanning electron microscopy (SEM) and X-ray Energy Dispersive Spectroscopy (EDS). It was found that aluminide coating improve the high temperature fatigue performance of MAR247 nickel based superalloy at 900 °C significantly. The coated MAR 247 nickel based superalloy was characterized by the stress amplitude response ranging from 350 MPa to 520 MPa, which is twice as large as that for the uncoated alloy.

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Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

Asian Journal of Civil Engineering ◽

10.1007/s42107-021-00351-6 ◽

2021 ◽

Author(s):

Haigen Cheng ◽

Cong Hu ◽

Yong Jiang

Keyword(s):

Fatigue Life ◽

High Performance ◽

Steel Structure ◽

Steel Structures ◽

Fatigue Tests ◽

Fatigue Performance ◽

Corrosive Media ◽

Joint Connection ◽

High Performance Steel ◽

The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

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