scholarly journals Usability of Ultrasonic Frequency Testing for Rapid Generation of High and Very High Cycle Fatigue Data

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2245
Author(s):  
Michael Fitzka ◽  
Bernd M. Schönbauer ◽  
Robert K. Rhein ◽  
Niloofar Sanaei ◽  
Shahab Zekriardehani ◽  
...  
Keyword(s):  
Strain Rate ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Ultrasonic Frequency ◽  
Cycle Fatigue ◽  
Reinforced Polymer ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Fibre Reinforced Polymer ◽  
Very High

Ultrasonic fatigue testing is an increasingly used method to study the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) properties of materials. Specimens are cycled at an ultrasonic frequency, which leads to a drastic reduction of testing times. This work focused on summarising the current understanding, based on literature data and original work, whether and how fatigue properties measured with ultrasonic and conventional equipment are comparable. Aluminium alloys are not strain-rate sensitive. A weaker influence of air humidity at ultrasonic frequencies may lead to prolonged lifetimes in some alloys, and tests in high humidity or distilled water can better approximate environmental conditions at low frequencies. High-strength steels are insensitive to the cycling frequency. Strain rate sensitivity of ferrite causes prolonged lifetimes in those steels that show crack initiation in the ferritic phase. Austenitic stainless steels are less prone to frequency effects. Fatigue properties of titanium alloys and nickel alloys are insensitive to testing frequency. Limited data for magnesium alloys and graphite suggest no frequency influence. Ultrasonic fatigue tests of a glass fibre-reinforced polymer delivered comparable lifetimes to servo-hydraulic tests, suggesting that high-frequency testing is, in principle, applicable to fibre-reinforced polymer composites. The use of equipment with closed-loop control of vibration amplitude and resonance frequency is strongly advised since this guarantees high accuracy and reproducibility of ultrasonic tests. Pulsed loading and appropriate cooling serve to avoid specimen heating.

Very High Cycle Fatigue in Pulsed High Power Spallation Neutron Source

2014 ◽  
Vol 891-892 ◽  
pp. 536-541 ◽  
Author(s):  
Zhi Hong Xiong ◽  
Masatoshi Futakawa ◽  
Takashi Naoe ◽  
Katsuhiro Maekawa
Keyword(s):  
Strain Rate ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Air Cooling ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Neutron Spallation Source ◽  
Ultrasonic Fatigue ◽  
Very High

Very high cycle fatigue degradation of type 316L austenitic stainless steel, which is used as the structural material of neutron spallation sources under intensive neutron irradiation environment, is investigated by using an ultrasonic fatigue testing machine. The strain rate imposed on the structure of neutron spallation source is almost equivalent to that produced in the testing machine. The temperature on the surface was controlled by the air-cooling. The effect of strain rate on the fatigue strength is recognized to increase the fatigue limit.

Effects of Strain Rate on the Very High Cycle Fatigue Properties of Low Alloy Steel SFVQ1A

2013 ◽  
Author(s):  
Takashi Nakamura ◽  
Hiroyuki Oguma ◽  
Shingo Nukaya
Keyword(s):  
Strain Rate ◽  
Crack Growth ◽  
Fatigue Limit ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Material Strength ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Stress Ratios ◽  
Very High

Uni-axial fatigue tests up to 109 cycles were conducted at two cyclic frequencies (10 and 250 Hz) under several stress ratios (R = −1, 0.1, and 0.5) to investigate the effects of strain rate on the very high cycle fatigue properties of SFVQ1A, which is equivalent to ASTM A508 Cl.3. Longer fatigue lives and 5% higher fatigue limit were measured at 250 Hz than those at 10 Hz for R = −1. Under R = 0.1 and R = 0.5, however, the fatigue properties did not differ between 10 and 250 Hz. Observations of fracture surfaces clarified that all fractures under R = −1 and R = 0.1 were caused by a general crack growth process from non-metallic inclusion(s) at the specimen surfaces. In contrast, the entire fracture surface under R = 0.5 was covered with a dimpled pattern. The fatigue mechanism was considered to be due to ductility exhaustion through ratcheting behavior under high mean stress. The longer fatigue lives and larger fatigue limit at 250 Hz under R = −1 was explained by the increase in crack growth resistance at a high strain rate based on crack growth behaviors and the da/dN-ΔK relation. No differences in fatigue properties between different frequencies under R = 0.1 and 0.5 were likely caused by the negligible effect of strain rate compared with the increase in material strength during fatigue loading, which resulted from strain hardening induced by maximum cyclic stress that was larger than yield stress.

Evaluation of Very High Cycle Fatigue Properties of β-Titanium Alloy by Using an Ultrasonic Tensile-Compressive Fatigue Testing Machine

2016 ◽  
Vol 725 ◽  
pp. 366-371 ◽  
Author(s):  
Reo Kasahara ◽  
Masato Nishikawa ◽  
Yoshinobu Shimamura ◽  
Keiichiro Tohgo ◽  
Tomoyuki Fujii
Keyword(s):  
Titanium Alloy ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Fracture Morphology ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High

β-titanium alloy has been developed recently because β-titanium alloy has better cold workability, proof stress, and tensile strength. In order to use β-titanium alloy for automobile parts subject to cyclic loading, very high cycle fatigue properties of β-titanium alloy should be investigated. In this study, very high cycle fatigue properties of β-titanium alloy Ti-22V-4Al were evaluated by using an ultrasonic fatigue testing method, which allows us to reduce a fatigue testing period to 1/100 − 1/1000 of that by using conventional testing methods. An S-N diagram and fracture morphology of Ti-22V-4Al in the very high cycle region were investigated. Fatigue failure was observed and subsurface fracture occurred in the very high cycle region.

Effect of Heat Treatment on Very High Cycle Fatigue Properties of TC4

2021 ◽  
Vol 881 ◽  
pp. 3-11
Author(s):  
Bo Han Wang ◽  
Li Cheng ◽  
Xun Chun Bao
Keyword(s):  
Heat Treatment ◽  
High Cycle Fatigue ◽  
Treatment Method ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Α Phase ◽  
Very High Cycle Fatigue ◽  
Significant Difference ◽  
Very High

The bimodal, equiaxed and Widmanstatten microstructures of TC4 titanium alloy were obtained through different heat treatment processes. The content of primary α phase in the bimodal and equiaxed microstructures was measured to be about 40% and 90%, and the average size was about 9.4μm and 7.9 μm. Three types of microstructure fatigue S-N curves are obtained, which are successively descending type, single-platform descending type and infinite life type. The order of very high cycle fatigue performance is Widmanstatten>equiaxed>bimodal, but the anti-fretting fatigue performance of Widmanstatten is the worst. The grain refinement makes the fatigue performance of the equiaxed better than that of the bimodal. The second process is determined as the best heat treatment method. There is no significant difference in the life of the crack propagation stage. The very high cycle fatigue life mainly depends on the crack initiation stage. In the bimodal and the equiaxed, the crack initiates in the primary α phase of the subsurface, and the crack in the Widmanstatten initiates in the coarse α 'grain boundary of the subsurface.

Ultrasonic Fatigue of Ti6Al4V in the Very High Cycle Fatigue Regime

2012 ◽  
pp. 831-838
Author(s):  
Stefan Heinz ◽  
Frank Balle ◽  
Guntram Wagner ◽  
Dietmar Eifler
Keyword(s):  
High Cycle Fatigue ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High
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