scholarly journals High cycle fatigue analysis in the presence of autofrettage compressive residual stress

2018 ◽  
Vol 41 (11) ◽  
pp. 2305-2320
Author(s):  
V. Okorokov ◽  
D. MacKenzie ◽  
Y. Gorash ◽  
M. Morgantini ◽  
R. van Rijswick ◽  
...  
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Fatigue Analysis ◽  
Cycle Fatigue

High-Cycle Fatigue Strength and Residual Stress in Welded Joints of Structural Steels

2004 ◽  
Author(s):  
Masahito Mochizuki ◽  
Masao Toyoda
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Fatigue Strength ◽  
Low Temperature ◽  
Weld Metal ◽  
Welded Joints ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Temperature Phase ◽  
Cycle Fatigue

Improvement of high-cycle fatigue strength by reducing residual stress in welded joints is studied in this paper. 10% Nickel and 10% Chromium are involved in the developed welding material for producing the property of thermal shrinkage by martensitic phase transformation at a low temperature and for generating compressive residual stress during cooling process. A cruciform fillet-welded joint is used for the numerical simulation of the thermal elastic-plastic finite-element analysis with coupling phase transformation effect. Distribution of the computed residual stress agrees with the measuring values by strain gauge. Compressive residual stress mostly distributes in the weld metal for both longitudinal and transverse directions with weld line. Fatigue test is also performed in order to clarify the effect of the developed weld material on fatigue strength. Developed weld metal has much higher characteristics for high-cycle fatigue strength than a conventional one. Increase effect of fatigue strength is shown by the modified Goodman diagram when residual stress is treated as mean stress. Weld metal with the property of low-temperature phase transformation is effective to reduce residual stress and to improve fatigue strength.

Effects of Laser Peening Treatment on High Cycle Fatigue and Crack Propagation Behaviors in Austenitic Stainless Steel

2009 ◽  
Author(s):  
Yasuo Ochi ◽  
Kiyotaka Masaki ◽  
Takashi Matsumura ◽  
Takaaki Ikarashi ◽  
Yuji Sano
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Propagation ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Laser Peening ◽  
Cycle Fatigue

Laser peening without protective coating (LPwC) treatment is one of surface enhancement techniques using impact wave of high pressure plasma induced by laser pulse irradiation. One of the effects of the LPwC treatment is expected to reduce the tensile residual stress and to induce the compressive residual stress in the surface layer of metallic materials. As a laser has no reaction force due to irradiation and also it has easy characteristics for remote control, the LPwC treatment is practically used as a technique for preventing the stress corrosion cracking (SCC) and for improving the fatigue strength of some structural materials. In this study, high cycle fatigue tests with four-points rotating bending loading were carried out on the non-peened and the LPwC treated low-carbon type austenitic stainless steel 316L in order to investigate the effects of the LPwC treatment on the high cycle fatigue strength and the surface fatigue crack propagation behavior. Two types of specimens were prepared; one was a smooth specimen, the other was a specimen with a pre-crack by the fatigue loading from a small artificial hole. As the results of the LPwC treatment, the high compressive residual stress was induced in the surface layer on the specimens, and the region of the compressive residual stress was about 1mm depth from the surface. The fatigue strength of the LPwC treated SUS316L was remarkably improved during the whole regime of the fatigue life up to the 108 cycles compared with the non-peened materials. Through the fracture mechanics investigation of the pre-cracked materials after the LPwC treatment, it became clear that the fatigue crack propagation was restrained by the LPwC treatment on the pre-cracked region, when the stress intensity factor range ΔK on the crack tip was under the value of 7.6 MPa√m.

Enhancement of Surface Properties by Laser Peening Without Coating

2006 ◽  
Author(s):  
Yuji Sano ◽  
Igor Altenberger ◽  
Berthold Scholtes ◽  
Kiyotaka Masaki ◽  
Yasuo Ochi ◽  
...  
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Laser Pulses ◽  
Cast Aluminum Alloy ◽  
Laser Peening ◽  
Cycle Fatigue ◽  
Cast Aluminum ◽  
Rotating Bending ◽  
Laser Peening Without Coating

Laser peening without coating (LPwC) has been applied to water-immersed materials using a water-penetrable light of a Q-switched and frequency-doubled Nd:YAG laser. Compressive residual stress of several hundred MPa was introduced at the surface of the materials. High-cycle fatigue (HCF) properties were evaluated through rotating-bending or push-pull type testing for an austenitic stainless steel (SUS316L), a titanium alloy (Ti-6Al-4V) and a cast aluminum alloy (AC4CH). LPwC prolonged the fatigue lives significantly, in spite of the increase in surface roughness ascribed to the ablative interaction of laser pulses with the materials.

Effects of process combinations of milling, grinding, and polishing on the surface integrity and fatigue life of GH4169 components

2019 ◽  
Vol 234 (3) ◽  
pp. 538-548
Author(s):  
Fang Quan ◽  
Zhitong Chen ◽  
Qiantong Li ◽  
Shimin Gao
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Boron Nitride ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Cubic Boron Nitride ◽  
Stress Profile ◽  
Cycle Fatigue ◽  
Squeezing Effect ◽  
Residual Stress Profile

The nickel-based superalloy GH4169 is widely applied in the aviation industry due to its outstanding mechanical properties. However, many blades of GH4169 are still produced by milling and manual polishing, which is costly and unreliable. In this article, GH4169 superalloy components manufactured with combination processes of milling, grinding, and polishing were comparatively studied involving surface integrity and fatigue performance. Test results indicate that the final polishing is the most dominant process that influences the high-cycle fatigue life of GH4169 components. Samples produced via cubic boron nitride grinding and numerical control polishing with a diamond-rubber wheel exhibit fatigue limits of 150 MPa higher than the milled and manually polished samples. Cubic boron nitride grinding induces a considerable compressive residual stress profile with a magnitude of -930 MPa and a depth of 200 μm. Milling induces a typical “hook” residual stress profile with 318 MPa at the surface. Polishing affects the machined surface by two ways, the removal effect and the squeezing effect. The squeezing effect induces a shallow compressive residual stress with approximately −1000 MPa, therefore improves the surface condition. However, inevitable omissions, scratches, texture disorders, and knock marks in hand-polishing are the main causes of the unstable high-cycle fatigue life of hand-polished components.

Smooth and notched fatigue performance of aging treated and shot peened ZK60 magnesium alloy

2010 ◽  
Vol 25 (7) ◽  
pp. 1375-1387 ◽  
Author(s):  
Wen-Cai Liu ◽  
Jie Dong ◽  
Ping Zhang ◽  
Xing-Wei Zheng ◽  
Wen-Jiang Ding ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Notched Specimen ◽  
Notched Specimens ◽  
Zk60 Alloy ◽  
Zk60 Magnesium Alloy

The influence of shot peening (SP) on high cycle fatigue (HCF) performance of smooth and notched specimens of hot-extruded ZK60 magnesium alloy was investigated and compared to that of hot-extruded and T5 aging-treated ZK60 magnesium alloy referred to as ZK60-T5. The increases in fatigue properties at the optimum Almen intensities were found to depend on the material states. In contrast to ZK60 alloy, higher smooth and notched fatigue properties for both unpeened and peened specimens were observed for ZK60-T5 alloy. Meanwhile, the improvement of fatigue life for notched specimen by SP was much more than that for the smooth specimen. The mechanism by which the compressive residual stress induced by SP resulted in the improvement of fatigue performance of smooth and notched specimens for ZK60 and ZK60-T5 alloys was discussed.

Deformation and Fatigue Analysis of Micro Thermal-Electrostatic Actuator Devices

Volume 3 ◽  
2004 ◽  
Author(s):  
Jeng-Nan Hung ◽  
Meng-Ju Lin ◽  
Chung-Li Hwan
Keyword(s):  
Applied Voltage ◽  
High Cycle Fatigue ◽  
Fatigue Analysis ◽  
Flexible Beam ◽  
Cycle Fatigue ◽  
Fatigue Cycle ◽  
Electrostatic Actuator ◽  
Beam Length ◽  
The Difference ◽  
Cold Arms

Micro thermal-electrostatic actuator devices are widely used in MEMS. However, the effect of structure sizes on deformation and fatigue is seldom discussed. In this work, the effect of structure sizes on deformation and fatigue is investigated. In this device, two beams called hot and cold arms with different width under applied voltage will have different elongation for there different width and the structure will cause the structure laterally bent. Theoretical solutions of deformation and stresses are derived. And numerical methods of finite element are used to analyze for details. The stresses obtained from the finite element are used in fatigue analysis. In the fatigue analysis, high-cycle fatigue model is used as the load in the elastic regime. Considering the accumulation of damage by fatigue being linear, Miner theory is used to estimate the life of the thermal-electrostatic devices under high-cycle fatigue. The result shows with the same length and flexible beam length connecting the hot and cold arms, the large width will cause larger displacement and stresses. However, the difference is not significant. It is also found that as the applied voltage increasing, the displacement and stresses will increase nonlinearly. With the same width and flexible beam length, the larger length will cause larger stresses and small displacement. For fatigue analysis, as the gap increasing and the length and width decreasing, the fatigue cycle increases. It shows when the length and gap are 220 and 5 μm, the fatigue cycle of 50 μm width is more than ten times of 90 μm width. When the width and gap are 50 and 5 μm, the fatigue cycle of 220 μm length is more than ten times of 260 μm length. When the length and width are 220 and 50 fatigue cycles of 50 μm width are more than ten times of 90 μm width, the difference of fatigue cycle between gap 9 and 5 μm is more than 10 times. However, the most significant effect on fatigue is the applied voltage. It shows the fatigue cycle decays very fast as the applied voltage increasing. When the applied voltages are 2 and 8 volts, the fatigue cycles will decrease from 1018 to less than 108. As the applied voltage being 25 volt, the fatigue cycle near zero. Therefore, the limit applied voltage is about 25 volt.

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