A novel method to improve fatigue behaviors of holed structures based on electromagnetic force

2022 ◽  
pp. 095440622110641
Author(s):  
Guo Zheng ◽  
Zengqiang Cao ◽  
Minghao Zhang
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Electromagnetic Force ◽  
Stress Measurement ◽  
Fatigue Cracks ◽  
Axial Direction ◽  
Novel Method ◽  
Fatigue Life Enhancement ◽  
Fatigue Failures ◽  
Improve Fatigue

In this study, a novel method stress wave strengthening (SWS) process based on electromagnetic force was proposed to improve the fatigue life of holed structures. Corresponding tests were carried out to explore the fatigue performance of SWS. Cold expansion (CE) was also investigated for comparison. The fatigue life of SWS and CE samples were evaluated, moreover, the mechanisms of fatigue failures and life enhancements were also discussed. Results showed that double-side SWS extended fatigue life significantly and reduced stiffness degradation more effectively with respect to CE process. Moreover, fatigue cracks commonly appeared at mid-planes of hole surfaces and horizontally grew in SWS samples, which differed a lot from CE samples. Through the residual stress measurement, it is seen that more uniform residual stress along axial direction can be obtained by SWS compared to CE, which can explain the fatigue life enhancement and failure mechanism of SWS method.

scholarly journals Improvement of Fatigue Life of GH3039 Superalloy by Laser Shock Peening

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3849
Author(s):  
Yang Tang ◽  
MaoZhong Ge ◽  
Yongkang Zhang ◽  
Taiming Wang ◽  
Wen Zhou
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Surface Profile ◽  
Optical Microscope ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Transmission Electron ◽  
Before And After ◽  
Shock Peening ◽  
Improve Fatigue

In order to improve fatigue life of GH3039 superalloy, GH3039 superalloy sheets were treated by laser shock peening (LSP). The microstructure of GH3039 superalloy before and after LSP was characterized using an optical microscope, transmission electron microscope (TEM), and X-ray diffractometer. The fatigue life of the samples with and without LSP was investigated by fatigue experiments. Moreover, surface profile and residual stress were also examined. Experimental results indicated that the grains in the surface layer of the LSP sample were remarkably refined and reached the nanometer scale. The average surface roughness increased from 0.024 μm to 0.19 μm after LSP. The average fatigue life of the laser treated samples was 2.01 times larger than that of the untreated specimens. Additionally, mathematical statistical analysis confirms that LSP has a significant influence on the fatigue life of GH3039 superalloy. The improvement of fatigue life for the laser processed GH3039 superalloy was mainly attributed to compressive residual stress and grain refinement generated by LSP.

Development of Instrument for Residual Stress Measurement in a 50 mm Inner Diameter Power Generation Pipes

2006 ◽  
Vol 524-525 ◽  
pp. 497-502
Author(s):  
M. Belassel ◽  
J. Pineault ◽  
M.E. Brauss
Keyword(s):  
Residual Stress ◽  
Thermal Fatigue ◽  
Power Plants ◽  
Stress Measurement ◽  
Turbine Blades ◽  
Axial Direction ◽  
Residual Stress Measurement ◽  
Measurement Validation ◽  
Inner Diameter ◽  
Development Of Instrument

With recent issues related to stress corrosion cracking (SCC) and thermal fatigue of power plant components, including nuclear steam generator tubing, condenser tubing, boiler tubes steam turbine blades, the residual stress in materials plays an important role in determining those susceptible for failure caused by fatigue or SCC. These residual stresses, combined with the applied stresses inherited from manufacturing and assembly can be tensile or compressive. The SCC can act in a corrosive environment only when the stresses in the material are tensile, thus leading to cracking of the component and the structure. Thermal fatigue can be originated from thermal gradients caused during the operation of power plants. Proto Manufacturing Limited, leader in the residual stress measurement and equipment development tailored for these applications has developed instruments capable of measuring residuals tresses in confined areas such as inner diameter of tubes as small as 50 mm in diameter, non-destructively in the direction of interest, axial direction. In this paper interesting examples of new x-ray diffraction instrument and measurement validation are presented along with application inside a 50 mm I.D.

Thermographic Determination of Fatigue Damage

1978 ◽  
Vol 100 (2) ◽  
pp. 200-203 ◽  
Author(s):  
J. A. Charles ◽  
F. J. Appl ◽  
J. E. Francis
Keyword(s):  
Fatigue Life ◽  
Mild Steel ◽  
Surface Temperature ◽  
Fatigue Damage ◽  
Fatigue Cracks ◽  
Temperature Distributions ◽  
Fatigue Failures

The energy released due to hysteresis effects in cyclically loaded materials can be used to predict where fatigue cracks are likely to initiate and to determine the stage of fatigue life. In the present study, thermography is used to monitor the surface temperature distributions on a series of double-notched, mild steel fatigue specimens cyclically loaded in bending. The results indicate that the fatigue life of the material encompasses three thermal stages, each of which is indicative of the fatigue damage the material has sustained. This information can be used to avoid in-service fatigue failures.

Microstructure and Fatigue Properties of Aero Aluminum Alloy Repaired by Laser Melt Casting

2011 ◽  
Vol 314-316 ◽  
pp. 1871-1875 ◽  
Author(s):  
Chang Liang Lu ◽  
Fang You Hu ◽  
Xu Ren Huang ◽  
De Xian Yi ◽  
Ai Yong Cui ◽  
...  
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Composite Powder ◽  
Crystal Size ◽  
Axial Direction ◽  
Fatigue Properties ◽  
Crystallographic Axis ◽  
Al Matrix Composite ◽  
Al Matrix

The paper presents a study of renovation of aerial aluminum alloy (LY12CZ) by laser melt casting with Al matrix composite powder. The microstructure of the melt casting zone was investigated, and the fatigue contrast test was carried out between the repaired specimens and the undamaged specimens. It is found that the melt casting zone consists of equiaxed crystals and columnar crystals. The equiaxed crystals distribute in the deposited layer and the crystal size is about 3~4μm. The columnar crystals whose axial direction size comes to 30μm~40μm exist near the interface with its crystallographic axis perpendicular to the interface. The fatigue life of specimens repaired by laser melt casting was shorter than no-damage specimens to a large extant, because of the flaws in the deposited layer engendered the origins of cracks; the columnar shape grains at the bottom of casting zone were easy to split under the tensile stress; the residual stress after the melt casting accelerated the initiation and growth of the cracks.

Residual Stress Management in Welding: Residual Stress Measurement and Improvement Treatments

2012 ◽  
Author(s):  
Jacob Kleiman ◽  
Yuri Kudryavtsev
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Stress Management ◽  
Stress Measurement ◽  
Industrial Applications ◽  
Welding Residual Stress ◽  
Residual Stress Measurement ◽  
Engineering Properties ◽  
Welded Structures

Residual stress (RS) can significantly affect engineering properties of materials and structural components, notably fatigue life, distortion, dimensional stability, corrosion resistance etc. Residual stresses play an exceptionally significant role in fatigue of welded elements. The influence of residual stresses on the multi-cycle fatigue life of butt and fillet welds can be compared with the effects of stress concentration. Even more significant are the effects of residual stresses on the fatigue life of welded elements in the case of relieving harmful tensile residual stresses and introducing beneficial compressive residual stresses in the weld toe zones. Residual stress management is a concept that addresses major aspects of residual stresses in welds and welded structures. According to the concept three major stages, i.e. RS determination, RS analysis and RS redistribution are considered and evaluated, either experimentally or theoretically to achieve the optimum performance of welded structures. All three stages as well as a number of new engineering tools such as ultrasonic computerized complex for residual stress measurement, UltraMARS, software for analysis of the effect of residual stresses on the fatigue life of welded elements and new technology and, based on it, compact system for beneficial redistribution of residual stresses by ultrasonic peening, UltraPeen will be discussed. Examples of industrial applications of the developed engineering tools for residual stress analysis and fatigue life improvement of welded elements and structures will be given.

Fatigue Assessment of Existing Riveted Bridges

2018 ◽  
Author(s):  
Henrik Mehlsen
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Visual Inspection ◽  
Fatigue Cracks ◽  
Repeated Loading ◽  
Fe Modelling ◽  
Railway Bridges ◽  
Loading And Unloading ◽  
Fatigue Failures ◽  
Thick Layers

Fatigue failure of bridges occurs after repeated loading and unloading and hence fatigue becomes more and more severe with time. A majority of all existing riveted bridges are not explicitly designed for fatigue failures. Bridge owners should therefore have focus on fatigue life of riveted bridges. It can be difficult to discover fatigue cracks by visual inspection due to thick layers of paint and the fact that the rivets themselves may hide the cracks. Hence, it may be necessary to determine critical joints and possible fatigue cracks by using FE-modelling. Identification of critical joints may also target future inspection efforts and highlight hidden details, which may call for special inspection measures to be implemented. This paper describes a fatigue study of 11 riveted railway bridges in Denmark that includes both visual inspections and FE-modelling of bridges.

Neutron Determination of Residual Stress in a Nitrided Notched Part

2005 ◽  
Vol 490-491 ◽  
pp. 251-256 ◽  
Author(s):  
Agnès Fabre ◽  
Laurent Barrallier
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Thermomechanical Treatment ◽  
Gear Tooth ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Improve Fatigue

Nitriding is an hardening thermomechanical treatment generally used to improve fatigue life of steel parts, like gear for example. Another effect of this treatment is generating superficial stress, influenced by nitriding conditions, composition of steel and geometry of the part. This work deals with the effect of shape on the residual stress profile obtain after nitriding on a gear tooth. The residual stress profile was determined using neutrons diffraction technique.

Rolling Contact Fatigue Life of 13Cr-2Ni-2Mo Stainless Steels which are Surface Treated by Induction Heating (IH) and Wide Peening Cleaning (WPC)

2018 ◽  
Vol 777 ◽  
pp. 366-371
Author(s):  
Takuto Yamada ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Induction Heating ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Life Evaluation ◽  
Contact Fatigue Life ◽  
Improve Fatigue Strength ◽  
Improve Fatigue

A new surface treatment, wide peening cleaning (WPC), was developed to improve fatigue strength of steels using shot peening and sandblast technologies. The combination of induction heating (IH) and WPC is expected to introduce higher compressive stress on the steels than single IH or single WPC. We investigated effect of IH and WPC on rolling contact fatigue life of 13Cr-2Ni-2Mo stainless steel. Vickers hardness and residual stress measurements, and RCF life evaluation using the Weibull distribution were carried out. It was found that the residual stress was introduced by WPC near the surface to improve life fatigue

The Relationship Between Design, Processing and Shot Peening on Wheel Plate Failures

2014 ◽  
Author(s):  
Steven L. Dedmon
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Cold Rolling ◽  
Shot Peening ◽  
Cyclic Stresses ◽  
Compressive Stresses ◽  
Freight Car ◽  
The Relationship ◽  
Fatigue Failures ◽  
Improve Fatigue

Wheel plate failures occur rarely in North American freight car service. When they do occur, derailments are a likely result. Shot peening has been used to improve fatigue life for more than 80 years and the efficacy of the process is now undisputed in reducing fatigue failures of parts subjected to high levels of cyclic stresses. The introduction of residual compressive stresses from shot peening is acknowledged as the reason for the improvement in fatigue life; comparable processes such as cold rolling, are successful for the same reason. Since residual stresses are so important to fatigue life, then design and processing prior to shot peening should have an equally important role. This investigation demonstrates some of the variables which are important to producing wheels resistant to plate fatigue failures.

Principle and Method of X-Ray Computer Tomography on Residual Stress Measurement

2005 ◽  
Vol 490-491 ◽  
pp. 208-212
Author(s):  
Yu-an Chen ◽  
Shang-qi Zhou ◽  
Qin Ren
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Computer Tomography ◽  
Lattice Spacing ◽  
Stress Measurement ◽  
Poisson Ratio ◽  
Depth Resolution ◽  
Axial Direction ◽  
Free Lattice ◽  
X Ray

X-ray computer tomography for non-destructively measuring residual stress with depth resolution was suggested to aim at improving of traditional X-ray stress analysis in this paper. Based on higher penetrating capacity of X-ray in low atomic order materials it could non-destructively measure three-dimensional residual stresses and calculate the stress free lattice spacing, d0, by current X-ray stress analyzer with taper slits. The evaluation of reliable results were controlled by three criteria, linear correlation coefficient, R, Poisson’ ratio, ν, and the stress free lattice spacing, d0. Finally, the residual stresses in the axial direction around the weld of arc Beryllium weldment could be calculated by this method.

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