Fatigue Behavior of Bridge Steel in Very Long Life Region

2010 ◽  
Vol 452-453 ◽  
pp. 269-272
Author(s):  
Yan Nu ◽  
Yi Yan Chen ◽  
Rui Juan Jiang ◽  
Dong Hui Fang ◽  
Qing Yuan Wang
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Loading Frequency ◽  
Mass Defect ◽  
Testing Technique ◽  
Bridge Steel ◽  
Ultrasonic Fatigue ◽  
Long Life ◽  
Corrugated Steel Web ◽  
Number Of Cycles

Q345qC steel is widely used in corrugated steel web. In this paper, the fatigue strength of Q345qC steel between 105~109 cycles was investigated using the ultrasonic fatigue testing technique, with a loading frequency of 20 kHz. The fracture surfaces of specimens were observed with scanning electron microscopy (SEM). The experimental results show that the S-N curve of Q345qC steel continues to decrease with the increase of the number of cycles between 105 and 109 cycles and does not generally exhibit a plateau beyond 107 cycles. The observation of fracture surface shows that the mechanism of fatigue failure is similar in both case of ultrasonic fatigue and conventional fatigue in long life regime. Cracks initiate from a mass defect of specimen surface or an interior inclusion.

Very Long Life Fatigue Behavior of Q345 Bridge Steel

2012 ◽  
Vol 217-219 ◽  
pp. 407-410
Author(s):  
Xiao Zhao
Keyword(s):  
Stress Ratio ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Ambient Air ◽  
Bridge Steel ◽  
Plate Specimen ◽  
Ultrasonic Fatigue ◽  
Long Life

Using the ultrasonic fatigue testing technique, specimens of Q345 bridge steel with two types of shape (round and plate) were performed in ambient air at room temperature with a stress ratio of R=-1. The very long life fatigue property of Q345 was studied and the initiation mechanisms of fatigue cracks were investigated and analyzed with SEM. The results show that the two types of specimen present different S-N curve characteristics in the region of 105-109 cycles. The S-N curve of round specimens shows continuously decreasing tendency, while the S-N curve of plate specimens has a steep decreasing step and an asymptotic horizontal one. The fatigue strength of round specimen is higher than that of plate specimen. Fatigue failure initiates from the surface before 107cycles with high stess level while at internal inclusion in the very long life fatigue regime.

Influence of Loading Frequency on Fatigue Behavior of High Strength Steel

2007 ◽  
Vol 353-358 ◽  
pp. 227-230 ◽  
Author(s):  
Nu Yan ◽  
Qing Yuan Wang ◽  
Q. Chen ◽  
J.J. Sun
Keyword(s):  
High Strength Steel ◽  
Fatigue Behavior ◽  
High Strength ◽  
Fatigue Tests ◽  
Test Machine ◽  
Ultrasonic Frequency ◽  
Loading Frequency ◽  
Frequency Level ◽  
Ultrasonic Fatigue ◽  
Long Life

In order to investigate the influence of loading frequency on the fatigue behaviors of the high strength steel, ultrasonic fatigue tests were carried out for a high-carbon-chromium steel and the results were compared with those of fatigue tests using conventional rotary bending fatigue test machine with a frequency of 52.5Hz. The different of fatigue strength at ultrasonic frequency level and conventional frequency level is very small and the S-N curve obtained from 20 kHz or 52.5 Hz shows the step-wise shape. The fatigue crack occurred from inclusions on the subsurface site in the long life regime and the typical surface fracture occurred in the short life one though the loading frequency level is different. It is indicated that ultrasonic fatigue method is an effective method to investigate the fatigue properties in super-long life region.

Very Long Life Fatigue Behavior of Bearing Steel AISI 52100

2005 ◽  
Vol 297-300 ◽  
pp. 1846-1851 ◽  
Author(s):  
Q.Y. Wang ◽  
Hong Yan Zhang ◽  
M.R. Sriraman ◽  
Shou Xin Li
Keyword(s):  
Fatigue Limit ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Bearing Steel ◽  
Aisi 52100 ◽  
Steel Aisi ◽  
Reversed Loading ◽  
Long Life ◽  
Number Of Cycles

For many applications, the understanding of very long life fatigue in materials becomes extremely important. In this study, the fatigue behavior of bearing steel GCr15 (conforming to AISI 52100) at very high number of cycles has been examined. Experiments on hourglass specimens were conducted in air at room temperature, for fully reversed loading condition (R=-1), using a piezoelectric fatigue testing machine operating at a frequency of 20kHz. The results indicate that the S-N data does not reach a horizontal asymptote (signifying the fatigue limit) at 107 cycles, as conventionally believed, and that the material can fracture up to 109 cycles. Therefore, to quote a fatigue limit at 107 cycles may not hold good for the material studied. The influence of defects (such as inclusions) on the crack initiation and fracture was analyzed by scanning electron microscopy.

Study on Bending Ultrasonic Fatigue Behavior of Sinter-Hardened Fe-2Cu-2Ni-1Mo-1C Materials Prepared by Warm Compaction

2010 ◽  
Vol 638-642 ◽  
pp. 1848-1853 ◽  
Author(s):  
Zhi Yu Xiao ◽  
Ling Zhou ◽  
Yuan Xun Shen ◽  
Tungwai Leo Ngai ◽  
Yuan Yuan Li
Keyword(s):  
Fatigue Strength ◽  
Crack Propagation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Bending Fatigue ◽  
Warm Compaction ◽  
Ultrasonic Fatigue ◽  
Number Of Cycles ◽  
Rupture Mode

Bending fatigue behavior of a sinter-hardened high density (7.4 g/cm3) Fe-2Cu-2Ni-1Mo-1C material fabricated by die-wall lubricated warm compaction of partially-diffuse alloyed powder was studied by bending ultrasonic fatigue testing. Results showed that fatigue strength decreases continuously with the increasing number of cycles. The fatigue failure yet occurs in the regime of exceeding 107 cycles and exhibits no traditional horizontal plateau between 106 and 107 cycles. Fatigue strength was 194 MPa, 239 MPa and 293 MPa at 108, 107 and 106 cycles respectively. Scanning electron microscopy revealed that cracks initiated from large pores on the surface and from pore clusters near the sub-surface. The fatigue cracks initiated both at single and multiple sites. Crack propagation was mainly in a trans-crystalline rupture mode. Fatigue striation and cleavage plane were observed in the crack propagation region and dimples were observed in the fracture zones.

Super Long Life Fatigue of AE42 and AM60 Magnesium Alloys

2006 ◽  
Vol 306-308 ◽  
pp. 181-186
Author(s):  
Q.Y. Wang ◽  
Hong Yan Zhang ◽  
S.R. Sriraman ◽  
S.L. Liu
Keyword(s):  
Magnesium Alloys ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Horizontal Asymptote ◽  
Ultrasonic Fatigue ◽  
Reversed Loading ◽  
Fatigue Characteristics ◽  
Long Life ◽  
Very High

Magnesium alloys, on account of their lightweight, find useful applications in the automotive sector. During service, they experience very high number of fatigue cycles. Therefore, the understanding of their long life fatigue behavior becomes extremely important. This is possible by using ultrasonic fatigue testing, which is the only feasible way of doing it. In this study, the two such alloys viz. AE42 and AM60 has been investigated for their long life fatigue characteristics under fully reversed loading conditions, using a piezoelectric fatigue testing machine operating at a frequency of 20 kHz. The S-N data does not reach a horizontal asymptote at 107 cycles in either of the alloys. However, the alloy AM60 seems to show a fatigue limit at about at 109 cycles. The fractures examined by scanning electron microscopy (SEM) were found to be brittle in character. In very high cycle fatigue conditions, the crack was found to initiate from the specimen subsurface.

Effect of Temperature and Loading Frequency on the Fatigue Behavior of Ti-17

2015 ◽  
Vol 664 ◽  
pp. 131-139 ◽  
Author(s):  
Jiu Kai Li ◽  
Yong Jie Liu ◽  
Qing Yuan Wang ◽  
Fang Hou
Keyword(s):  
Room Temperature ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Effect Of Temperature ◽  
Fatigue Properties ◽  
Frequency Effect ◽  
Loading Frequency ◽  
Ultrasonic Fatigue ◽  
Increasing Temperature

A high-temperature ultrasonic fatigue testing system was developed to evaluate the gigacycle fatigue properties of Ti-17. Ultrasonic (20 kHz) fatigue tests were performed at room temperature, 200°C and 350°C, respectively. The dynamic Young’s modulus and fatigue endurance limit decrease with increasing temperature linearly. Rotating bending (50 Hz) tests were performed to evaluate the influence of loading frequency at room temperature, 200°C and 350°C, respectively. There is an obviously loading frequency effect at elevated temperature, although no loading frequency effect at room temperature.

scholarly journals Very High Cycle Fatigue Behavior of Carbon Manganese Steels

2010 ◽  
Vol 146-147 ◽  
pp. 1780-1783
Author(s):  
Hong Qian Xue ◽  
Danièle Wagner
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Effect Of Temperature ◽  
Testing System ◽  
Loading Frequency ◽  
Ultrasonic Fatigue ◽  
Carbon Manganese Steels ◽  
Temperature Scanning ◽  
Initial Results ◽  
Manganese Steels

An ultrasonic fatigue testing system capable of operating at temperatures at 250 has been introduce to study the fatigue behavior of carbon manganese steels (A42 and A48) and loading frequency of approximately 20 kHz. Endurance limit results were comparable to those generated at room temperature to determine the effect of temperature. Scanning electron microscopy was then used to determine the initiation sites and the failure mechanisms. Initial results indicate that fatigue strength decrease a little at 250 , interior inclusions were the major microstructural feature responsible for crack initiation in the alloy.

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.

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

Metals ◽  
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.

Low Tension-Tension Cycle Fatigue Properties of 301 Stainless Steel Thin Sheets

2013 ◽  
Vol 351-352 ◽  
pp. 887-891
Author(s):  
Shi Ming Cui ◽  
Rui Dong Wang ◽  
Yong Jie Liu ◽  
Tao Long ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Stress Ratio ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Testing System ◽  
Loading Frequency ◽  
Thin Sheets ◽  
Cycle Fatigue ◽  
Low Tension

By using of a micro mechanical fatigue testing system, low tension-tension cycle fatigue properties of 301 stainless steel thin sheets with a thickness of 0.1 mm were studied. The effects of loading frequency and stress ratio were considered in the tests. The results show the S-N curves descend continuously in the low cycle regime. Cyclic σ-N curve was obtained according to the traditional fatigue theory. It agrees well with the experimental data, showing that the traditional fatigue research methods are also suitable to describe thin sheets in a certain extent. With the increase of loading stress ratio, the fatigue strength of thin sheets is increased. There is an evident effect of frequency on the fatigue behavior of the thin sheets.

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