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Jianyu Zhang - One of the best experts on this subject based on the ideXlab platform.
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The effect of Mean Stress on tension-torsion high-cycle fatigue failure of 2A12-T4 aluminum alloy
2020Co-Authors: Jianyu ZhangAbstract:The aim of present paper is to study the effect of Mean tensile Stress and Mean Shear Stress on multi-axial fatigue failure. Fatigue experiments with funnel-shape specimens of 2A12-T4 aluminium alloy are carried out to investigate the effects of Mean tensile Stress and Mean Shear Stress on the multi-axial high-cycle fatigue failure under proportional and non-proportional loading conditions. Loading is given by Soderberg rules in the experiments of Mean tensile Stress. The results show that fatigue lives reduces gradually with the increase of tensile Stress ratio and the reduction are more significant under non-proportional loading, which indicates that for the multi-axial high-cycle fatigue, the effect of Mean tensile Stress is more severe than that in unaxial fatigue. With increasing of Mean tensile Stress, the direction of initiation and expansion of crack remain basically unchanged, however, the transverse step increases gradually. The experiment results on the effect of Mean Shear Stress show that there are no remarkable effects on fatigue lives under proportional loading. However, the existence of Mean Shear Stress makes a significant reduction of fatigue lives under nonproportional loading. With the increasing of Mean Shear Stress, the black and brilliant feather in the initiation region becomes apparent. The direction of initiation and expansion of crack remain basically unchanged. Different from the previous, there is no transverse step. INTRODUCTION Most of the structural components suffer multi-axial cyclic loading. There are many loading factors e.g. Stress amplitude ratio, phase angle and Mean Stresses of tension and torsion, affect the multi-axial fatigue lives. The effect of these loading parameters on multi-axial fatigue failure is so complicated that no widely accepted agreements have been reached, especially the effect of Mean Stresses [1-7]. Currently, studies show that Mean tensile Stress has a negative impact and Mean compression Stress has a beneficial effect on multi-axial fatigue lives, which is the same as the uniaxial failure [8, 9]. The relationship between Stress amplitude and Mean tensile Stress can be correlated by Goodman and Gerber rules as long as the maximum Stress does not exceed the yield Stress of material in multi-axial fatigue [10, 11]. About the effect of Mean Shear Stress, Wang and Miller et al [12] found that the presence of Shear Stress makes the fatigue * Corresponding author: Tel: (86 10) 8233 8663; E-mail: jyzhang@buaa.edu.cn
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multiaxial high cycle fatigue failure of 30crmnsia steel with Mean tension Stress and Mean Shear Stress
International Journal of Fatigue, 2019Co-Authors: Jianyu ZhangAbstract:Abstract Experiments had been performed to investigate the effect of the Mean tension Stress and Mean Shear Stress on the multiaxial fatigue failure of 30CrMnSiA steel. The crack growth path was observed under a metallographic microscope. The stage I cracks were always initiated on the MSSA planes and propagated approximately 20–100 μm for the different load conditions. The stage II crack propagated approximately 400–1000 μm along the MN plane for in-phase loading. The stage II crack initially propagated along the MN plane and quickly deviated from it for 90° out-of-phase loading. Crack initiation and early propagation (
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effect of Mean Shear Stress on torsion fatigue failure behavior of 2a12 t4 aluminum alloy
International Journal of Fatigue, 2014Co-Authors: Jianyu Zhang, Qingshan XiaoAbstract:Abstract Fatigue experiments with solid cylindrical bar specimens were carried out to investigate the effects of Mean Shear Stress on the torsion fatigue failure behavior of 2A12-T4 aluminum alloy. The torsion S–N curves under different values of Mean Shear Stress were obtained. Experiment results showed that fatigue life under the same Shear Stress amplitude gradually reduces with increasing the Mean Shear Stress, when Mean Shear Stress is lower than a threshold value. Macro-analysis and micro-analysis of specimen fracture appearance were conducted in order to obtain the fracture characteristics for different Mean Shear Stress values under torsion fatigue loading.
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Tension–torsion high-cycle fatigue failure analysis of 2A12-T4 aluminum alloy with different Stress ratios
International Journal of Fatigue, 2011Co-Authors: Jianyu ZhangAbstract:Abstract Fatigue experiments with solid cylindrical bar specimens are carried out to investigate effects of axial Stress ratio and Mean Shear Stress on the tension–torsion high-cycle fatigue failure of 2A12-T4 aluminum alloy under proportional ( φ = 0°) and non-proportional loading ( φ = 90°). Experiment results about effects of axial Stress ratio show that fatigue life reduces gradually with the increase of axial Stress ratio. The reduction is more significant under non-proportional loading than that proportional loading. Experiment results about effects of Mean Shear Stress show that there are no remarkable effects on fatigue life under proportional loading. However, the existence of Mean Shear Stress makes a significant reduction of fatigue life under non-proportional loading. Macro-analysis and micro-analysis of specimen fracture appearance is conducted in order to obtain the fracture characteristics with different Stress ratios under tension–torsion loading.
Jonathan Merzeau - One of the best experts on this subject based on the ideXlab platform.
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influence of Mean Shear Stress on the torsional fatigue behaviour of 34crnimo6 steel
International Journal of Fatigue, 2018Co-Authors: Luis Pallaressantasmartas, J Albizuri, Alexander Aviles, Nicolas Saintier, Jonathan MerzeauAbstract:Abstract This study provides a theoretical and experimental investigation of the effect of static Shear Stresses on the high-cycle fatigue behaviour of a 34CrNiMo6 high-strength steel under quenched and tempered conditions. Torsion S–N curves under different Mean Shear Stresses were obtained. Experimental results show that an increase in Mean Shear Stress yields a gradual reduction in Shear-Stress amplitude that the material can withstand without failure. The results for this steel agree well with the Smith’s hypothesis for ductile steels, which states that the effect of the torsional Mean Stresses on the torsional fatigue limit is negligible as long as the maximum Shear Stress is within the torsional yield strength. Taking into account the results collected from the literature and the experimental results on torsional fatigue of 34CrNiMo6 steel, an extension of the theory of Crossland is proposed to include the Mean-Shear-Stress effect. Its application to the torsional fatigue case with Mean Shear Stresses can be interpreted in terms of a balance of the energy of distortion. Macro-analyses of the specimen fracture appearance were conducted to obtain the fracture characteristics for different Mean-Shear-Stress values under torsion fatigue loading.
Qingshan Xiao - One of the best experts on this subject based on the ideXlab platform.
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effect of Mean Shear Stress on torsion fatigue failure behavior of 2a12 t4 aluminum alloy
International Journal of Fatigue, 2014Co-Authors: Jianyu Zhang, Qingshan XiaoAbstract:Abstract Fatigue experiments with solid cylindrical bar specimens were carried out to investigate the effects of Mean Shear Stress on the torsion fatigue failure behavior of 2A12-T4 aluminum alloy. The torsion S–N curves under different values of Mean Shear Stress were obtained. Experiment results showed that fatigue life under the same Shear Stress amplitude gradually reduces with increasing the Mean Shear Stress, when Mean Shear Stress is lower than a threshold value. Macro-analysis and micro-analysis of specimen fracture appearance were conducted in order to obtain the fracture characteristics for different Mean Shear Stress values under torsion fatigue loading.
Mark Sheplak - One of the best experts on this subject based on the ideXlab platform.
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A system for vector measurement of aerodynamic wall Shear Stress
2017 19th International Conference on Solid-State Sensors Actuators and Microsystems (TRANSDUCERS), 2017Co-Authors: Casey Barnard, David Mills, Mark SheplakAbstract:This paper describes a sensor system designed for vector measurement of aerodynamic wall Shear Stress. The microelectromechanical systems (MEMS) prototype utilizes a serpentine tether flexure for dual-axis in-plane motion. Capacitive gap pairs coupled to a multi-frequency modulation/demodulation system allow for independent transduction across both axes. Sensor performance includes an average dynamic/Mean Shear Stress sensitivity of 0.16 mV/Pa, corresponding to a minimum detectable signal of 0.3 mPa at 1.128 kHz. Pressure rejection is calibrated at 74 dB, with in-plane cross-axis isolation in excess of 24 dB.
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modern developments in Shear Stress measurement
Progress in Aerospace Sciences, 2002Co-Authors: Jonathan W. Naughton, Mark SheplakAbstract:Abstract This paper reviews three relatively modern categories of skin-friction measurement techniques that are broadly classified as microelectromechanical systems (MEMS)-based sensors, oil-film interferometry, and liquid crystal coatings. The theory, development, limitations, uncertainties, and misconceptions of each of these techniques are presented. Current and future uses of the techniques are also discussed. From this review, it is evident that MEMS-based techniques possess great promise, but require further development to become reliable measurement tools. Oil-film techniques have enhanced capabilities and greater accuracy compared to conventional Shear-Stress measurement techniques (i.e., Preston tube, Clauser plot, etc.) and, as a result, are being employed with increasing frequency. Liquid crystal coatings are capable of making measurements of Mean Shear-Stress vector distributions over a region of a model, but complex calibration and testing requirements limit their usefulness.
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Modern developments in Shear-Stress measurement
Progress in Aerospace Sciences, 2002Co-Authors: Jonathan W. Naughton, Mark SheplakAbstract:This paper reviews three relatively modern categories of skin-friction measurement techniques that are broadly classified as microelectromechanical systems (MEMS)-based sensors, oil-film interferometry, and liquid crystal coatings. The theory, development, limitations, uncertainties, and misconceptions of each of these techniques are presented. Current and future uses of the techniques are also discussed. From this review, it is evident that MEMS-based techniques possess great promise, but require further development to become reliable measurement tools. Oil-film techniques have enhanced capabilities and greater accuracy compared to conventional Shear-Stress measurement techniques (i.e., Preston tube, Clauser plot, etc.) and, as a result, are being employed with increasing frequency. Liquid crystal coatings are capable of making measurements of Mean Shear-Stress vector distributions over a region of a model, but complex calibration and testing requirements limit their usefulness. © 2002 Elsevier Science Ltd. All rights reserved.
Luis Pallaressantasmartas - One of the best experts on this subject based on the ideXlab platform.
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influence of Mean Shear Stress on the torsional fatigue behaviour of 34crnimo6 steel
International Journal of Fatigue, 2018Co-Authors: Luis Pallaressantasmartas, J Albizuri, Alexander Aviles, Nicolas Saintier, Jonathan MerzeauAbstract:Abstract This study provides a theoretical and experimental investigation of the effect of static Shear Stresses on the high-cycle fatigue behaviour of a 34CrNiMo6 high-strength steel under quenched and tempered conditions. Torsion S–N curves under different Mean Shear Stresses were obtained. Experimental results show that an increase in Mean Shear Stress yields a gradual reduction in Shear-Stress amplitude that the material can withstand without failure. The results for this steel agree well with the Smith’s hypothesis for ductile steels, which states that the effect of the torsional Mean Stresses on the torsional fatigue limit is negligible as long as the maximum Shear Stress is within the torsional yield strength. Taking into account the results collected from the literature and the experimental results on torsional fatigue of 34CrNiMo6 steel, an extension of the theory of Crossland is proposed to include the Mean-Shear-Stress effect. Its application to the torsional fatigue case with Mean Shear Stresses can be interpreted in terms of a balance of the energy of distortion. Macro-analyses of the specimen fracture appearance were conducted to obtain the fracture characteristics for different Mean-Shear-Stress values under torsion fatigue loading.