scholarly journals On the Influence of Control Type and Strain Rate on the Lifetime of 50CrMo4

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1458
Author(s):  
Max Benedikt Geilen ◽  
Josef Arthur Schönherr ◽  
Marcus Klein ◽  
Dominik Sebastian Leininger ◽  
Alexander Giertler ◽  
...  
Keyword(s):  
Strain Rate ◽  
Fatigue Testing ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Carbon Steels ◽  
Cyclic Test ◽  
Test Results ◽  
Strain Rate Effects ◽  
Rate Dependent ◽  
Ultrasonic Fatigue

In this study, we investigate the influence of control type and strain rate on the lifetime of specimens manufactured from 50CrMo4. This influence is described by a strain rate dependent method that uses cyclic stress strain curves to correct displacement-controlled cyclic test results. The objective of this correction is to eliminate the stress related differences between displacement-controlled cyclic test results and force-controlled cyclic test results. The method is applied to the results of ultrasonic fatigue tests of six different combinations of heat treatment, specimen geometry (notch factor) and atmosphere. In a statistical analysis, the corrected results show an improved agreement with test results obtained on conventional fatigue testing equipment with similar specimens: the standard deviation in combined data sets is significantly reduced (p = 4.1%). We discuss the literature on intrinsic and extrinsic strain rate effects in carbon steels.

An Investigation of Size Effect on Fatigue Property of 3000 MPa-Class Mould Steel Under Ultrasonic Fatigue Testing

2012 ◽  
Vol 239-240 ◽  
pp. 88-91
Author(s):  
Wen Jie Peng ◽  
Hui Cai Long ◽  
Li Yu ◽  
Huan Xue ◽  
Bao Wen Qiu ◽  
...  
Keyword(s):  
Size Effect ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Property ◽  
High Strength ◽  
Fatigue Tests ◽  
Test Results ◽  
Fatigue Specimen ◽  
Ultrasonic Fatigue

Ultrasonic fatigue testing was conducted for 3000 MPa-class mould steel to investigate the fatigue behavior. The fatigue specimen is designed particularly due to the ultra-high strength. Ultrasonic fatigue tests are conduced using two types of specimen sizes and the test results are compared to investigate the size effect on the fatigue property.

An Investigation of the Fatigue Property of Ultra-High Strength Mould Steel at 130 Hz and 20 kHz

2012 ◽  
Vol 239-240 ◽  
pp. 96-99 ◽  
Author(s):  
Wen Jie Peng ◽  
Li Yu ◽  
Hui Cai Long ◽  
Huan Xue ◽  
Lan Xiang Kuang ◽  
...  
Keyword(s):  
Size Effects ◽  
Fatigue Testing ◽  
Fatigue Property ◽  
High Strength ◽  
Fatigue Tests ◽  
Frequency Effect ◽  
Test Results ◽  
Fatigue Specimen ◽  
Ultrasonic Fatigue

In this paper, the fatigue property of ultra-high strength mould steel is investigated. The fatigue specimen is designed particularly due to the ultra-high strength. Fatigue tests are conduced using ultrasonic and conventional fatigue testing machines respectively. The same geometry and size of the ultrasonic fatigue specimens and conventional fatigue specimens are adopted to overcome the size effects. The test results are compared to investigate the frequency effect.

Gigacycle Fatigue of Welded Joints of Structural Materials (A Review)

2016 ◽  
Vol 17 ◽  
pp. 14-30 ◽  
Author(s):  
Okechukwu P. Nwachukwu ◽  
Alexander V. Gridasov ◽  
Ekaterina A. Gridasova
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Structural Materials ◽  
Fatigue Tests ◽  
Material Defects ◽  
Graphite Cast Iron ◽  
Ultrasonic Fatigue ◽  
Materials Used ◽  
Fatigue Failures

This review looks into the state of gigacycle fatigue behavior of some structural materials used in engineering works. Particular attention is given to the use of ultrasonic fatigue testing machine (USF-2000) due to its important role in conducting gigacycle fatigue tests. Gigacycle fatigue behavior of most materials used for very long life engineering applications is reviewed.Gigacycle fatigue behavior of magnesium alloys, aluminum alloys, titanium alloys, spheroid graphite cast iron, steels and nickel alloys are reviewed together with the examination of the most common material defects that initiate gigacycle fatigue failures in these materials. In addition, the stage-by-stage fatigue crack developments in the gigacycle regime are reviewed. This review is concluded by suggesting the directions for future works in gigacycle fatigue.

Cyclic and High Strain Behavior of Titanium Alloys Used for Riser Components

2008 ◽  
Author(s):  
C. F. G. Baxter
Keyword(s):  
Stress Relaxation ◽  
Titanium Alloys ◽  
Elevated Temperatures ◽  
Fatigue Testing ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Cyclic Behavior ◽  
Fatigue Data ◽  
Stress Ratios

Grades 23 and 29 titanium alloys are becoming more commonly used offshore for critical components of riser systems. Many of these components, such as compact flanges, operate at high mean strains due to make-up loads, often close to or above yield. Hitherto, weld fatigue data collected at low mean strains have been used for prediction of fatigue lives of such components. However, these analyses have resulted in short but adequate lives. The objective of this work was, therefore, to derive fatigue data that could be applied to components operating at high strains and over a large range of stress ratios. This necessitated strain-controlled fatigue testing. Cyclic material properties evaluated from the tests are presented. In addition, it was found that sustained strain load, a type of stress relaxation that, unlike normal stress relaxation, does not require elevated temperatures, affected the cyclic behavior It also affects the distribution of make up stresses. This phenomenon was also investigated and it was shown that the cyclic stress/strain curve, readily derived from strain-controlled fatigue tests, accounted for sustained strain load effects.

Effects of Continuous Strain Rate Changing on Environmental Fatigue for Stainless Steels in PWR Environment

2010 ◽  
Author(s):  
Yuichiro Nomura ◽  
Seiji Asada ◽  
Takao Nakamura ◽  
Masakazu Tanaka
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
Water Environment ◽  
Sine Wave ◽  
Fatigue Tests ◽  
Integral Model ◽  
Strain Rates ◽  
Test Results ◽  
Approach Method ◽  
The Difference

The strain rates in actual transients of operating plants are not constant and changing momentarily. A large number of fatigue tests under stepwise strain rate changing conditions were performed to develop a method for evaluating fatigue life under varying strain rate conditions. Based on these test results, a strain base integral model known as the named the modified rate approach method was developed and verified. However it was reported recently that in the case of sine wave fatigue tests in BWR environment, the fatigue life was two to six times longer than the fatigue life predicted by the modified rate approach method. For this paper, in order to confirm whether the same tendency is observed in PWR environment, fatigue tests of sine wave were performed of SS316 in simulated PWR water environment. As the result, the difference of fatigue life by sine wave test reported in BWR environment was not observed between experimental and predicted life in PWR environment and the modified rate approach method was applicable under continuous strain rate changing condition.

scholarly journals Ultrasonic fatigue testing under multiaxial loading conditions on a railway wheel

2019 ◽  
Vol 300 ◽  
pp. 18003 ◽  
Author(s):  
Pedro R. da Costa ◽  
Henrique Soares ◽  
Luís Reis ◽  
Manuel Freitas
Keyword(s):  
Stress Ratio ◽  
Fatigue Testing ◽  
Fatigue Tests ◽  
Cycle Frequency ◽  
Railway Wheel ◽  
Material Specimen ◽  
Hydraulic Machines ◽  
Wide Range ◽  
Ultrasonic Fatigue ◽  
Very High

Ultrasonic fatigue testing is a relative recent fatigue methodology that uses resonant principles for the induction of stress cycles in a specific designed material specimen. This experimental method can apply very high cycle frequency, the most common frequency being 20 kHz, and was created with the main purpose of studying material fatigue life in the Very High Cycle Fatigue regime between 107 and 109 cycles with a higher performance of time and energy wise in comparison to conventional servo-hydraulic machines. In this study an improvement of an already built multiaxial ultrasonic fatigue machine in the Instituto Superior Técnico laboratories was carried out to specific designed specimens and afterwards a fatigue study was made for a material of a worn-out railway wheel. The particular design of the specimen was achieved by numerical and experimental analysis based on previous experiments and components. Thermographic imaging and the application of rosette strain gauges to the main throat of the specimens were conducted in order to validate the improved specimen design and to understand the real induced stresses on the specimen. Afterwards fatigue tests were conducted for several specimens for a wide range of stresses with a stress ratio R=-1 and an axial vs shear stress ratio of around 0.58. Results were analysed and fracture analysis was also carried out.

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.

scholarly journals Ultrasonic fatigue experiments with biaxial cruciform specimens

2019 ◽  
Vol 300 ◽  
pp. 18004
Author(s):  
Pedro R. da Costa ◽  
Diogo Montalvão ◽  
Manuel Freitas ◽  
Luis Reis
Keyword(s):  
Fatigue Testing ◽  
Complex Loading ◽  
Fatigue Tests ◽  
Dynamic Loads ◽  
Structural Components ◽  
Ultrasonic Fatigue ◽  
Innovative Materials ◽  
Wide Energy ◽  
Intended Behaviour ◽  
Very High

Fatigue studies of materials in simple or complex loading systems for any given lifetime is object of continuous research. This is due to the advancements on mechanical and structural components, as well as for new and innovative materials, which implies the knowledge of a materials response to all dynamic loads. The fatigue failure regime beyond what was once considered to be the fatigue limit (infinite life) is characterized between 107 and 109, known as Very High Cycle Fatigue regime. Due to the time consuming and wide energy consumption of conventional fatigue testing for such regime, fatigue tests under ultrasonic actuators are being used, capable of applying the dynamic loads at around 20 kHz. Nowadays, several variants of ultrasonic fatigue tests were already proposed and tested but it is still a somewhat limited fatigue test if compared to the conventional servo-hydraulic fatigue testing machines of general use. In this study, biaxial in plane stresses are induced in specially designed cruciform specimens with ultrasonic fatigue testing resonant principals. Two geometries were numerically analysed, manufactured and experimentally tested, the in-phase tension-tension (T-T) specimen and the out-of-phase compression-tension (C-T) specimen. All specific designed geometries go under a thorough numerical and several experiments analysis for their validation. The specimens showing a correct and as intended behaviour are led to failure.

A method for the strain rate dependent correction for control type of fatigue tests

2020 ◽  
Vol 138 ◽  
pp. 105726 ◽  
Author(s):  
M.B. Geilen ◽  
M. Klein ◽  
M. Oechsner ◽  
M. Kaffenberger ◽  
K. Störzel ◽  
...  
Keyword(s):  
Strain Rate ◽  
Fatigue Tests ◽  
Rate Dependent

Strain-Rate Effects in the Propagation of Torsional Plastic Waves

1966 ◽  
Vol 33 (4) ◽  
pp. 917-923 ◽  
Author(s):  
W. E. Baker ◽  
C. H. Yew
Keyword(s):  
Strain Rate ◽  
Shear Strain ◽  
Cross Sections ◽  
Pure Copper ◽  
High Rate ◽  
Strain Rate Effects ◽  
Rate Dependent ◽  
Dependent Theory ◽  
Lower Strain ◽  
Rate Effects

A new method was developed for determining the dynamic stress-strain relationships of materials subjected to high rate of torsional loading. In addition, an investigation of propagation of torsional plastic waves in a long tube was conducted. Commercially pure copper was used throughout both investigations. In the material property studies, shear strains up to 20 percent and shear strain rates to 2100/sec were obtained. The results indicated that copper exhibits significantly lower strain-rate effects than those previously obtained by the longitudinal loading method. In the studies of plastic wave propagation, shear strain-time records at several cross sections along the tube were compared with computed results obtained from the strain-rate-independent and strain-rate-dependent theories. It is concluded that the computed results based on the strain-rate-dependent theory give better agreement with the experiments.

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