scholarly journals Influences of Residual Stress, Surface Roughness and Peak-Load on Micro-Cracking: Sensitivity Analysis

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 320
Author(s):  
Jairan Nafar Dastgerdi ◽  
Fariborz Sheibanian ◽  
Heikki Remes ◽  
Hossein Hosseini Toudeshky
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Crack Formation ◽  
Peak Load ◽  
Crack Size ◽  
Effective Parameters ◽  
Load Range ◽  
Load Effect ◽  
Damage Initiation ◽  
Load Conditions

This paper provides further understanding of the peak load effect on micro-crack formation and residual stress relaxation. Comprehensive numerical simulations using the finite element method are applied to simultaneously take into account the effect of the surface roughness and residual stresses on the crack formation in sandblasted S690 high-strength steel surface under peak load conditions. A ductile fracture criterion is introduced for the prediction of damage initiation and evolution. This study specifically investigates the influences of compressive peak load, effective parameters on fracture locus, surface roughness, and residual stress on damage mechanism and formed crack size. The results indicate that under peak load conditions, surface roughness has a far more important influence on micro-crack formation than residual stress. Moreover, it is shown that the effect of peak load range on damage formation and crack size is significantly higher than the influence of residual stress. It is found that the crack size develops exponentially with increasing peak load magnitudes.

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

scholarly journals Measuring the Casimir Forces with an Adhered Cantilever: Analysis of Roughness and Background Effects

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 64
Author(s):  
Ivan A. Soldatenkov ◽  
Anastasiya A. Yakovenko ◽  
Vitaly B. Svetovoy
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Short Distance ◽  
Technological Progress ◽  
Experimental Information ◽  
Casimir Forces ◽  
Raw Data ◽  
Micromechanical Devices ◽  
Negligible Contribution

Technological progress has made possible precise measurements of the Casimir forces at distances less than 100 nm. It has enabled stronger constraints on the non-Newtonian forces at short separations and improved control of micromechanical devices. Experimental information on the forces below 30 nm is sparse and not precise due to pull-in instability and surface roughness. Recently, a method of adhered cantilever was proposed to measure the forces at small distances, which does not suffer from the pull-in instability. Deviation of the cantilever from a classic shape carries information on the forces acting nearby the adhered end. We calculate the force between a flat cantilever and rough Au plate and demonstrate that the effect of roughness dominates when the bodies approach the contact. Short-distance repulsion operating at the contact is included in the analysis. Deviations from the classic shape due to residual stress, inhomogeneous thickness of the cantilever, and finite compliance of the substrate are analysed. It is found that a realistic residual stress gives a negligible contribution to the shape, while the finite compliance and inhomogeneous thickness give measurable contributions that have to be subtracted from the raw data.

scholarly journals Effects of Roughness on Stresses in an Oxide Scale Formed on a Superalloy Substrate

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 479
Author(s):  
Yang Zhao ◽  
Fan Sun ◽  
Peng Jiang ◽  
Yongle Sun
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Residual Stresses ◽  
Oxide Scale ◽  
Rough Surface ◽  
Alumina Scale ◽  
Growth Stress ◽  
Oxide Growth ◽  
Substrate Thickness ◽  
Roughness Effect

The effects of surface roughness on the stresses in an alumina scale formed on a Fecralloy substrate are investigated. Spherical indenters were used to create indents with different radii and depths to represent surface roughness and then the roughness effect was studied comprehensively. It was found that the residual stresses in the alumina scale formed around the rough surface are almost constant and they are dominated by the curvature rather than the depth of the roughness. Oxidation changes the surface roughness. The edge of the indent was sharpened after oxidation and the residual stress there was released presumably due to cracking. The residual stresses in the alumina scale decrease with increase in oxidation time, while the substrate thickness has little effect, given that the substrate is thicker than the alumina scale. Furthermore, the effect of roughness on the oxide growth stress is analysed. This work indicates that the surface roughness should be considered for evaluation of stresses in coatings.

scholarly journals Study on the Effect of Grinding Pressure on Material Removal Behavior Performed on a Self-Designed Passive Grinding Simulator

2021 ◽  
Vol 11 (9) ◽  
pp. 4128
Author(s):  
Peng-Zhan Liu ◽  
Wen-Jun Zou ◽  
Jin Peng ◽  
Xu-Dong Song ◽  
Fu-Ren Xiao
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Service Life ◽  
Material Removal ◽  
Removal Rate ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Temperature ◽  
Grinding Efficiency

Passive grinding is a new rail grinding strategy. In this work, the influence of grinding pressure on the removal behaviors of rail material in passive grinding was investigated by using a self-designed passive grinding simulator. Meanwhile, the surface morphology of the rail and grinding wheel were observed, and the grinding force and temperature were measured during the experiment. Results show that the increase of grinding pressure leads to the rise of rail removal rate, i.e., grinding efficiency, surface roughness, residual stress, grinding force and grinding temperature. Inversely, the enhancement of grinding pressure and grinding force will reduce the grinding ratio, which indicates that service life of grinding wheel decreases. The debris presents dissimilar morphology under different grinding pressure, which reflects the distinction in grinding process. Therefore, for rail passive grinding, the appropriate grinding pressure should be selected to balance the grinding quality and the use of grinding wheel.

Study on the effect mechanisms of pre-stress on residual stress and surface roughness in PSHG

2016 ◽  
Vol 88 (9-12) ◽  
pp. 3243-3256 ◽  
Author(s):  
Yansheng Deng ◽  
Shichao Xiu ◽  
Xiaoliang Shi ◽  
Cong Sun ◽  
Yushi Wang
Keyword(s):  
Residual Stress ◽  
Surface Roughness

Structure-Soil Interaction of Buried Corrugated Steel Arch Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 2112-2117
Author(s):  
Miao Xin Zhang ◽  
Bao Dong Liu ◽  
Peng Fei Li ◽  
Zhi Mao Feng
Keyword(s):  
Finite Element ◽  
Steel Structures ◽  
Internal Force ◽  
Structural Deformation ◽  
Fe Model ◽  
Soil Pressure ◽  
Load Range ◽  
Finite Element Program ◽  
Load Conditions ◽  
Peak Value

Corrugated steel plate and surrounding soils are working together to share the load in buried corrugated steel structures. It is complicated to consider the structure-soil interaction, so the finite element method has already become the chief means of complicated structure analysis. Based on a practical project, considering structure-soil interaction, by using the finite element program of ANSYS, the paper set up a 2-D FE model and analyzed the soil pressure, the structural deformation and the internal force under different load conditions in detail. The analysis shows that structure-soil interaction has brought about stresses redistribution of surrounding soils, and adverse effects of soil pressure and displacement were limited. The variation range of soil pressure on the crown of arch increases with the load increases and the peak value of soil pressure approach to the code value and a rebound appears in the vehicle load range. The tendencies of vertical soil displacement are nearly the same to different load conditions, and the peak value of moments has an obvious change and can be influenced greatly by deflective load.

In Situ Thin Film Stress Measurements – A Path to Understanding the Structure and Morphology of Electron Beam Evaporated ZnS

2002 ◽  
Vol 749 ◽  
Author(s):  
Vincent Barrioz ◽  
Stuart J. C. Irvine ◽  
D. Paul
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Electron Beam ◽  
Stress Reduction ◽  
Float Glass ◽  
Film Stress ◽  
Intrinsic Stress ◽  
Ex Situ ◽  
Stress Measurements

ABSTRACTZnS is a material of choice in the optical coating industry for its optical properties and broad transparency range. One of the drawbacks of ZnS is that it develops high compressive intrinsic stress resulting in large residual stress in the deposited layer. This paper concentrates on the evolution of residual stress reduction in ZnS single layers, depending upon their deposition rate or the substrate temperature during deposition (i.e. 22 °C and 133 °C). The substrate preparation is addressed for consideration of layer adhesion. Residual stress of up to − 550 MPa has been observed in amorphous/poor polycrystalline ZnS layers, deposited on CMX and Float glass type substrates, by electron beam evaporation at 22 °C, with a surface roughness between 0.4 and 0.8 nm. At 133 °C, the layer had a surface roughness of 1 nm, the residual stress in the layer decreased to − 150 MPa, developing a wurtzite structure with a (002) preferred orientation. In situ stress measurements, using a novel optical approach with a laser-fibre system, were carried out to identify the various sources of stress. A description of this novel in situ stress monitor and its advantages are outlined. The residual stress values were supported by two ex situ stress techniques. The surface morphology analysis of the ZnS layers was carried out using an atomic force microscope (AFM), and showed that stress reduced layers actually gave rougher surfaces.

Effect of Surface Machining on the Fatigue Life of Low Alloy Steel for Hydrogen Pressure Vessels

2007 ◽  
Author(s):  
Yoru Wada ◽  
Ryoji Ishigaki ◽  
Yasuhiko Tanaka ◽  
Tadao Iwadate ◽  
Keizo Ohnishi
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Pressure Vessels ◽  
Hydrogen Gas ◽  
Annealed Specimen ◽  
Surface Machining ◽  
Hydrogen Fatigue ◽  
Effect Of Surface

The effect of surface machining on fatigue life in high pressure hydrogen gas was investigated. The test was conducted under the elastic range under 45MPa gaseous hydrogen environment by the ground specimen which were machined so that the surface roughness to be Rmax = 19μm(Mark: 19s), 26μm(26s) and 93μm(93s) and by the polished specimen which are prepared so that the surface roughness to be Rmax = 1μm(1s), 3.6μm(3.6s) and 10μm(10s). The hydrogen fatigue life of ground specimens was considerably reduced with increasing surface roughness as compared to the fatigue life in air at the same surface condition. On the other hand, for the annealed conditions of the ground specimen, the reduction by hydrogen effect was fairly small. The residual stress for the ground specimen at the surface rises sharply in tension while the residual stress for the annealed specimen was nearly equal to zero. We have shown that the hydrogen fatigue damage can be evaluated by obtaining the information about residual stress on surface, stress concentration by maximum surface roughness and the threshold stress intensity SH above which hydrogen fatigue damage occurs.

Evaluation of contact fatigue life of a wind turbine carburized gear considering gradients of mechanical properties

2018 ◽  
Vol 28 (8) ◽  
pp. 1170-1190 ◽  
Author(s):  
Wei Wang ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Zhangdong Sun
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Heavy Duty ◽  
Initial Residual Stress ◽  
Contact Fatigue Life ◽  
Carburized Gear ◽  
Load Conditions

Case hardening processes such as carburizing are extensively applied in heavy-duty gears used in wind turbines, ships, high-speed rails, etc. Contact fatigue failure occurs commonly in engineering practice, thus reduces reliabilities of those machines. Rolling contact fatigue life of a carburized gear is influenced by factors such as the gradients of mechanical properties and profile of initial residual stress. In this regard, the study of contact fatigue life of carburized gears should be conducted with the consideration of those aspects. In this study, a finite element elastic–plastic contact model of a carburized gear is developed which takes the gradients of hardness and initial residual stress into account. Initial residual stress distribution and the hardness profile along the depth are obtained through experimental measurements. The effect of the hardness gradient is reflected by the gradients of yield strength and fatigue parameters. The modified Fatemi–Socie strain-life criterion is used to estimate the rolling contact fatigue life of the heavy-duty carburized gear. Numerical results reveal that according to the Fatemi–Socie fatigue life criterion, rolling contact fatigue failure of the carburized gear will first initiate at subsurface rather than surface. Compared with the un-carburized gear, the rolling contact fatigue lives of the carburized gear under all load conditions are significantly improved. Under heavy load conditions, the carburized layer significantly reduces the fatigue damage mainly due to the benefit to inhibit the accumulation of plasticity. Influence of the residual stress is also investigated. Under the nominal load condition, compared with the residual stress-free case, the existence of the tensile residual stress causes remarkable deterioration of the rolling contact fatigue life while the compressive residual stress with the same magnitude leads to a moderate growth of the rolling contact fatigue life. As the load becomes heavier when plasticity becomes notable, the influence of the initial residual stress on the life is somewhat weakened.

Analytical Modeling of Surface Roughness, Hardness and Residual Stress Induced by Deep Rolling

2016 ◽  
Vol 26 (2) ◽  
pp. 876-884 ◽  
Author(s):  
Frederico C. Magalhães ◽  
Alexandre M. Abrão ◽  
Berend Denkena ◽  
Bernd Breidenstein ◽  
Tobias Mörke
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Analytical Modeling ◽  
Deep Rolling
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