The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Weixing Yao - One of the best experts on this subject based on the ideXlab platform.
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local stress Strain Field intensity approach to fatigue life prediction under random cyclic loading
International Journal of Fatigue, 2001Co-Authors: Deguang Shang, Dakang Wang, Weixing YaoAbstract:Abstract According to the characteristic of the local behavior of fatigue damage, on the basis of stress Field intensity approach, a theory of local stress–Strain Field intensity for fatigue damage at the notch is developed in this paper, which can take account of the effects of the local stress–Strain gradient on fatigue damage at the notch. In order to calculate the local stress–Strain Field intensity parameters, an incremental elastic-plastic finite element analysis under random cyclic loading is used to determine the local stress–Strain response. A local stress–Strain Field intensity approach to fatigue life prediction is proposed by means of elastic-plastic finite element method for notched specimens. This approach is used to predict fatigue crack initiation life, and good correlation was observed with U-shape notched specimens for normalized 45 steel.
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Local stress–Strain Field intensity approach to fatigue life prediction under random cyclic loading
International Journal of Fatigue, 2001Co-Authors: Deguang Shang, Dakang Wang, Weixing YaoAbstract:Abstract According to the characteristic of the local behavior of fatigue damage, on the basis of stress Field intensity approach, a theory of local stress–Strain Field intensity for fatigue damage at the notch is developed in this paper, which can take account of the effects of the local stress–Strain gradient on fatigue damage at the notch. In order to calculate the local stress–Strain Field intensity parameters, an incremental elastic-plastic finite element analysis under random cyclic loading is used to determine the local stress–Strain response. A local stress–Strain Field intensity approach to fatigue life prediction is proposed by means of elastic-plastic finite element method for notched specimens. This approach is used to predict fatigue crack initiation life, and good correlation was observed with U-shape notched specimens for normalized 45 steel.
Deguang Shang - One of the best experts on this subject based on the ideXlab platform.
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local stress Strain Field intensity approach to fatigue life prediction under random cyclic loading
International Journal of Fatigue, 2001Co-Authors: Deguang Shang, Dakang Wang, Weixing YaoAbstract:Abstract According to the characteristic of the local behavior of fatigue damage, on the basis of stress Field intensity approach, a theory of local stress–Strain Field intensity for fatigue damage at the notch is developed in this paper, which can take account of the effects of the local stress–Strain gradient on fatigue damage at the notch. In order to calculate the local stress–Strain Field intensity parameters, an incremental elastic-plastic finite element analysis under random cyclic loading is used to determine the local stress–Strain response. A local stress–Strain Field intensity approach to fatigue life prediction is proposed by means of elastic-plastic finite element method for notched specimens. This approach is used to predict fatigue crack initiation life, and good correlation was observed with U-shape notched specimens for normalized 45 steel.
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Local stress–Strain Field intensity approach to fatigue life prediction under random cyclic loading
International Journal of Fatigue, 2001Co-Authors: Deguang Shang, Dakang Wang, Weixing YaoAbstract:Abstract According to the characteristic of the local behavior of fatigue damage, on the basis of stress Field intensity approach, a theory of local stress–Strain Field intensity for fatigue damage at the notch is developed in this paper, which can take account of the effects of the local stress–Strain gradient on fatigue damage at the notch. In order to calculate the local stress–Strain Field intensity parameters, an incremental elastic-plastic finite element analysis under random cyclic loading is used to determine the local stress–Strain response. A local stress–Strain Field intensity approach to fatigue life prediction is proposed by means of elastic-plastic finite element method for notched specimens. This approach is used to predict fatigue crack initiation life, and good correlation was observed with U-shape notched specimens for normalized 45 steel.
Dakang Wang - One of the best experts on this subject based on the ideXlab platform.
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local stress Strain Field intensity approach to fatigue life prediction under random cyclic loading
International Journal of Fatigue, 2001Co-Authors: Deguang Shang, Dakang Wang, Weixing YaoAbstract:Abstract According to the characteristic of the local behavior of fatigue damage, on the basis of stress Field intensity approach, a theory of local stress–Strain Field intensity for fatigue damage at the notch is developed in this paper, which can take account of the effects of the local stress–Strain gradient on fatigue damage at the notch. In order to calculate the local stress–Strain Field intensity parameters, an incremental elastic-plastic finite element analysis under random cyclic loading is used to determine the local stress–Strain response. A local stress–Strain Field intensity approach to fatigue life prediction is proposed by means of elastic-plastic finite element method for notched specimens. This approach is used to predict fatigue crack initiation life, and good correlation was observed with U-shape notched specimens for normalized 45 steel.
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Local stress–Strain Field intensity approach to fatigue life prediction under random cyclic loading
International Journal of Fatigue, 2001Co-Authors: Deguang Shang, Dakang Wang, Weixing YaoAbstract:Abstract According to the characteristic of the local behavior of fatigue damage, on the basis of stress Field intensity approach, a theory of local stress–Strain Field intensity for fatigue damage at the notch is developed in this paper, which can take account of the effects of the local stress–Strain gradient on fatigue damage at the notch. In order to calculate the local stress–Strain Field intensity parameters, an incremental elastic-plastic finite element analysis under random cyclic loading is used to determine the local stress–Strain response. A local stress–Strain Field intensity approach to fatigue life prediction is proposed by means of elastic-plastic finite element method for notched specimens. This approach is used to predict fatigue crack initiation life, and good correlation was observed with U-shape notched specimens for normalized 45 steel.
Stéphane Le Dizès - One of the best experts on this subject based on the ideXlab platform.
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Stability of the Rankine vortex in a multipolar Strain Field
Physics of Fluids, 2001Co-Authors: Christophe Eloy, Stéphane Le DizèsAbstract:In this paper, the linear stability of a Rankine vortex in an n-fold multipolar Strain Field is addressed. The flow geometry is characterized by two parameters: the degree of azimuthal symmetry n which is an integer and the Strain strength e which is assumed to be small. For n=2, 3 and 4 (dipolar, tripolar and quadrupolar Strain Fields, respectively), it is shown that the flow is subject to a three-dimensional instability which can be described by the resonance mechanism of Moore and Saffman [Proc. R. Soc. London, Ser. A 346, 413 (1975)]. In each case, two normal modes (Kelvin modes), with the azimuthal wave numbers separated by n, resonate and interact with the multipolar Strain Field when their axial wave numbers and frequencies are identical. The inviscid growth rate of each resonant Kelvin mode combination is computed and compared to the asymptotic values obtained in the large wave numbers limits. The instability is also interpreted as a vorticity stretching mechanism. It is shown that the inviscid gr...
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Stability of the Rankine vortex in a multipolar Strain Field
Physics of Fluids, 2001Co-Authors: Christophe Eloy, Stéphane Le DizèsAbstract:In this paper, the linear stability of Rankine vortex in a n-fold multipolar Strain Field is addressed. The flow geometry is characterized by two parameters: the degree of azimuthal symmetry n which is an integer and the Strain strength e which is assumed to be small. For n=2, 3 and 4 (dipolar, tripolar and quadripolar Strain Field respectively), it is shown that the flow is subject to a three-dimensional instability which can be described by the resonance mechanism of Moore & Saffman [Proc. Roy. Soc. Lond. A 346, 413 (1975)]. In each case, two normal modes (Kelvin modes), with azimuthal wavenumbers separated by n, resonate and interact with the multipolar Strain Field when their axial wavenumbers and frequencies are identical. The inviscid growth rate of each resonant Kelvin mode combination is computed and compared to the asymptotic values obtained in the large wavenumbers limits.The instability is also interpreted as a vorticity stretching mechanism. It is shown that the inviscid growth rate is maximum when the perturbation vorticity is preferentially aligned with the direction of stretching. Viscous effects are also considered for the distinguished scalings: [nu] =O(e) for n=2 and 3, [nu]= O(e^2) for n=4, where [nu] is the dimensionless viscosity. The instability diagram showing the most unstable mode combination and its growth rate as a function of viscosity is obtained and used to discuss the role of viscosity in the selection process. Interestingly, for n=2 in a high viscosity regime, a combination of Kelvin modes of azimuthal wavenumbers m=0 and m=2 is found to be more unstable than the classical helical modes m= 1 or -1. For n=3 and 4, the azimuthal structure of the most unstable Kelvin mode combination is shown to be strongly dependent on viscous effects. The results are finally discussed in the context of turbulence and compared to recent observations of vortex filaments.
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Three-dimensional instability of Burgers and Lamb-Oseen vortices in a Strain Field
Journal of Fluid Mechanics, 1999Co-Authors: Christophe Eloy, Stéphane Le DizèsAbstract:The linear stability of the Burgers and Lamb-Oseen vortices is addressed when the vortex of circulation C and radius r is subjected to an additional Strain Field of rate s perpendicular to the vorticity axis. The resulting non-axisymmetric vortex is analysed in the limit of large Reynolds number Re = C / \nu and small Strain s
Yao Xuefeng - One of the best experts on this subject based on the ideXlab platform.
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Digital speckle correlation method with compensation technique for Strain Field measurements
Optics and Lasers in Engineering, 2003Co-Authors: Jin Guanchang, Wu Zhen, Bao Nikeng, Yao XuefengAbstract:In the Strain Field measurements, especially in large Strain Field measurements, the correlation coefficient values obtained by the digital speckle correlation method are usually very low due to the relative pixel movement of the subset. The measuring error, therefore, is increased. A primary method, that is called compensation algorithm, is introduced for improving the correlation coefficient. A flow scheme with the compensation algorithm of our software is developed and some improved techniques for reducing the calculation time and error are discussed in the paper. After obtaining a set of displacement data with high correlation coefficient, a de-noise wavelet processing is adopted. It is obvious that the measuring accuracy of the Strain Field is better then before. A Strain Field of testing experiment is performed with this compensation technique. The correlation coefficients can increase from 0.70 to 0.99, which will be of much benefit for the improvements of the measuring accuracy.
