Microscale High-Cycle Fatigue Testing by Dynamic Micropillar Compression Using Continuous Stiffness Measurement

During technical operation, high performance materials are partially exposed to high frequency cyclic loading conditions. Furthermore, the small strains in the very high cycle fatigue (VHCF)-regime lead to accumulative damage which causes crack initiation related to an appropriate local deformation leading to final fatal fracture. At the same time, quite high requirements with regard to high number of cycles without any damage are demanded for many applications. Fields of application of these light-weight, but expensive materials, are e.g. in the automobile industry (e.g. engine blocks, cylinder heads, brakes).The fatigue behavior of Al-matrix composites (Al-MMCs) reinforced by alumina particles (15 vol.% Al2O3) or short fibers (20 vol.% Saffil), respectively, was already intensively studied in the LCF and HCF range. The present study is focusing on investigations in the very high cycle fatigue regime at stress amplitudes up to 140 MPa to reach fatigue life of about 1010 cycles. All experiments were carried out using an ultrasonic fatigue testing device under symmetric loading conditions (R=-1). Fatigue tests were accompanied by in situ thermography measurements to record the temperature of the whole specimen and to find “hot spots” indicating changes in microstructure and therefore the initiation or growth of cracks. Moreover, the resonant frequency as well as the damage parameter were evaluated to determine the beginning of damage. For a better understanding of the damage mechanism (matrix decohesion, matrix failure or failure of reinforcement) all fractured surfaces were investigated by scanning electron microscopy. The combination of these methods contributes to a better understanding of the underlying mechanism of damage in aluminum-matrix-composites.

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Very High Cycle Fatigue Testing under Spectrum Loading for Endurance Limit Structural Design

Journal of the American Helicopter Society ◽

10.4050/jahs.65.012008 ◽

2020 ◽

Vol 65 (1) ◽

pp. 1-7

Author(s):

David T. Rusk ◽

Robert E. Taylor ◽

Bruce A. Pregger ◽

Luis J. Sanchez

Keyword(s):

Fatigue Test ◽

Test Data ◽

High Cycle Fatigue ◽

Fatigue Testing ◽

Crack Nucleation ◽

Peak Stress ◽

Material Behavior ◽

Cycle Fatigue ◽

Very High Cycle Fatigue ◽

Very High

A program has recently concluded that generated fatigue test data for the influence of a rotorcraft main rotor blade root bending spectrum (Helix) on the crack nucleation mechanisms in 7075-T651 aluminum. High-frequency tests were performed that generated spectrum fatigue failures out to nearly 109 cycles. Fractographic examination showed a distinct change in crack nucleation from slip initiated to inclusion-initiated cracking as the spectrum peak stress level was increased. Spectrum life predictions were made using three different baseline constant-amplitude S-N curves, one using a traditional rotorcraft original equipment manufacturer fitting methodology, one using the high-cycle fatigue (HCF) portion of a strainlife curve, and one that was fitted to S-N data with test lives out to 3×108 cycles. The spectrum life prediction using the S-N curve that properly modeled material behavior in the very high cycle fatigue regime provided a good correlation to the spectrum fatigue test data. Predictions using the other S-N curves were highly conservative.

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Recent Advances in Very High Cycle Fatigue Behavior of Metals and Alloys—A Review

Metals ◽

10.3390/met10091200 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1200

Author(s):

Ashutosh Sharma ◽

Min Chul Oh ◽

Byungmin Ahn

Keyword(s):

Crack Initiation ◽

High Cycle Fatigue ◽

Fatigue Testing ◽

Fatigue Behavior ◽

Simulation Studies ◽

Cycle Fatigue ◽

Future Directions ◽

Very High Cycle Fatigue ◽

Ultrasonic Fatigue ◽

Very High

We reviewed the research and developments in the field of fatigue failure, focusing on very-high cycle fatigue (VHCF) of metals, alloys, and steels. We also discussed ultrasonic fatigue testing, historical relevance, major testing principles, and equipment. The VHCF behavior of Al, Mg, Ni, Ti, and various types of steels were analyzed. Furthermore, we highlighted the major defects, crack initiation sites, fatigue models, and simulation studies to understand the crack development in VHCF regimes. Finally, we reviewed the details regarding various issues and challenges in the field of VHCF for engineering metals and identified future directions in this area.

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Fatigue life time modelling of Cu and Au fine wires

MATEC Web of Conferences ◽

10.1051/matecconf/201816506002 ◽

2018 ◽

Vol 165 ◽

pp. 06002

Author(s):

Golta Khatibi ◽

Ali Mazloum-Nejadari ◽

Martin Lederer ◽

Mitra Delshadmanesh ◽

Bernhard Czerny

Keyword(s):

Fatigue Life ◽

Strain Rate ◽

High Cycle Fatigue ◽

Fatigue Testing ◽

Low Cycle Fatigue ◽

Load Ratio ◽

Life Time ◽

Material Model ◽

Cycle Fatigue ◽

Rate Dependency

In this study, the influence of microstructure on the cyclic behaviour and lifetime of Cu and Au wires with diameters of 25μm in the low and high cycle fatigue regimes was investigated. Low cycle fatigue (LCF) tests were conducted with a load ratio of 0.1 and a strain rate of ~2e-4. An ultrasonic resonance fatigue testing system working at 20 kHz was used to obtain lifetime curves under symmetrical loading conditions up to very high cycle regime (VHCF). In order to obtain a total fatigue life model covering the low to high cycle regime of the thin wires by considering the effects of mean stress, a four parameter lifetime model is proposed. The effect of testing frequency on high cycle fatigue data of Cu is discussed based on analysis of strain rate dependency of the tensile properties with the help of the material model proposed by Johnson and Cook.

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High-Cycle Fatigue and Thermal Dissipation Investigations for Low Carbon Steel Q345

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.664.305 ◽

2015 ◽

Vol 664 ◽

pp. 305-313 ◽

Cited By ~ 4

Author(s):

Han Qing Liu ◽

Qing Yuan Wang ◽

Zhi Yong Huang ◽

Zhen Jie Teng

Keyword(s):

Carbon Steel ◽

High Cycle Fatigue ◽

Fatigue Testing ◽

Low Carbon Steel ◽

Infrared Camera ◽

Fatigue Property ◽

Thermal Dissipation ◽

Loading Frequency ◽

Cycle Fatigue ◽

Low Carbon

Carbon steel is a kind of metallic material that widely used in construction, machinery, manufacturing and other domains. In the mechanical structure system, long-term cyclic stress may cause the mechanical components failure. In this work, the characteristic of fatigue crack propagate in low carbon steel Q345 and the effect of loading frequency to the fatigue property of Q345 steel were investigated. Meanwhile, the dispersion of high-cycle fatigue of life of the Q345 steel under high fatigue testing frequency was analyzed, and the P-S-N curve with the test data was given out. With the help of infrared camera, temperature rise curve during fatigue test was analyzed to study the thermal dissipation of Q345 steel.

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Very high cycle fatigue testing of concrete using ultrasonic cycling

Materials Testing ◽

10.3139/120.111021 ◽

2017 ◽

Vol 59 (5) ◽

pp. 438-444 ◽

Cited By ~ 8

Author(s):

Ulrike Karr ◽

Reinhard Schuller ◽

Michael Fitzka ◽

Andreas Denk ◽

Alfred Strauss ◽

...

Keyword(s):

High Cycle Fatigue ◽

Fatigue Testing ◽

Cycle Fatigue ◽

Very High Cycle Fatigue ◽

Very High

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Design and Development of an Ultrasonic Fatigue Testing System for Very High Cycle Fatigue

10.4271/2020-01-0183 ◽

2020 ◽

Author(s):

Paul Catalin Ilie ◽

Xavier Lesperance ◽

Ayhan Ince

Keyword(s):

High Cycle Fatigue ◽

Fatigue Testing ◽

Testing System ◽

Cycle Fatigue ◽

Design And Development ◽

Very High Cycle Fatigue ◽

Ultrasonic Fatigue ◽

Very High

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EDF/NRC High-Cycle Fatigue Database Proposal

Volume 1A: Codes and Standards ◽

10.1115/pvp2015-45146 ◽

2015 ◽

Author(s):

T. P. Métais ◽

G. Stevens ◽

G. Blatman ◽

J. C. Le Roux ◽

R. L. Tregoning

Keyword(s):

Stainless Steels ◽

Data Exchange ◽

High Cycle Fatigue ◽

Fatigue Testing ◽

Austenitic Stainless Steels ◽

Nuclear Regulatory Commission ◽

Fatigue Curve ◽

Research Data ◽

Cycle Fatigue ◽

Fatigue Data

Revised fatigue curves for austenitic stainless steels are currently being considered by several organizations in various countries, including Japan, South Korea, and France. The data available from laboratory tests indicate that the mean air curve considering all available austenitic material fatigue data may be overly conservative compared to a mean curve constructed from only those data representative of a particular type of material. In other words, developing separate fatigue curves for each of the different types of austenitic materials may prove useful in terms of removing excess conservatism in the estimation of fatigue lives. In practice, the fatigue curves of interest are documented in the various international design codes. For example, in the 2009 Addenda of Section III of the ASME Boiler and Pressure Vessel (BPV) Code [1], a revised design air fatigue curve for austenitic materials was implemented that was based on NRC research models [2]. More recently, in Japan, various industrial groups have joined their efforts to create the Design Fatigue Curve Sub-committee (DCFS) with the objective to reassess the fatigue curves [3]. In France, EDF/AREVA and CEA are developing a new fatigue curve for austenitic stainless steels [4]. More specifically, in 2014, EDF presented a paper on high-cycle fatigue analysis which demonstrated that the factor on the strain amplitude could be reduced from 2 to 1.4 for the RCC-M austenitic stainless steel grades [5]. Recently, discussions between EDF and the U.S. Nuclear Regulatory Commission (NRC) have led both parties to recognize that there is a need to exchange worldwide research data from fatigue testing to promote a common, vetted database available to all researchers. These discussions have led EDF and NRC to pursue a collaborative agreement and associated fatigue data exchange, with the intent to assemble all available fatigue data for austenitic materials into a standardized format. The longer term objective is to perform common analyses on the consolidated set of data. This paper summarizes the intent and of the preliminary results of this cooperation and also provides insights from both organizations on possible future activities and participation in the global exchange of fatigue research data.

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