The Experts below are selected from a list of 5193 Experts worldwide ranked by ideXlab platform
Sunil Kumar Srivastava - One of the best experts on this subject based on the ideXlab platform.
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Modified shear lag theory based fatigue crack growth life prediction model for short-fiber reinforced metal matrix composites
International Journal of Fatigue, 2015Co-Authors: Abhishek Tevatia, Sunil Kumar SrivastavaAbstract:Closed form expressions for the low cycle and high cycle fatigue crack growth lives have been derived for the randomly-planar oriented short-fiber reinforced metal matrix composites under the total strain-controlled conditions. The modeling was based on fatigue-fracture mechanics theory under both the small scale and the large scale yielding conditions. The modified shear lag theory was considered to describe the effect of yielding strength. The present model is essentially a crack growth model because crack initiation period in short fiber reinforced metal matrix composite is much shorter; hence, not assumed to play a dominant role in the calculation of fatigue crack growth life. The effects of short-fiber volume fraction (Vf), cyclic strain Hardening exponent (n′) and cyclic strain Hardening Coefficient (K′) on the fatigue crack propagation life are analyzed for aluminum based SFMMCs at different levels of cyclic plastic strain values. It is observed that the influence of fatigue crack growth resistance increases with increase in cyclic strain Hardening exponent (n′) and decreases when volume fraction (Vf) or cyclic strain Hardening Coefficient (K′) increases. The present MSL theory based fatigue crack growth life prediction model is an alternative of modified rule of mixture and strengthening factor models. The predicted fatigue life for SFMMC shows good agreement with the experimental data for the low cycle and high cycle fatigue applications.
Abhishek Tevatia - One of the best experts on this subject based on the ideXlab platform.
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Modified shear lag theory based fatigue crack growth life prediction model for short-fiber reinforced metal matrix composites
International Journal of Fatigue, 2015Co-Authors: Abhishek Tevatia, Sunil Kumar SrivastavaAbstract:Closed form expressions for the low cycle and high cycle fatigue crack growth lives have been derived for the randomly-planar oriented short-fiber reinforced metal matrix composites under the total strain-controlled conditions. The modeling was based on fatigue-fracture mechanics theory under both the small scale and the large scale yielding conditions. The modified shear lag theory was considered to describe the effect of yielding strength. The present model is essentially a crack growth model because crack initiation period in short fiber reinforced metal matrix composite is much shorter; hence, not assumed to play a dominant role in the calculation of fatigue crack growth life. The effects of short-fiber volume fraction (Vf), cyclic strain Hardening exponent (n′) and cyclic strain Hardening Coefficient (K′) on the fatigue crack propagation life are analyzed for aluminum based SFMMCs at different levels of cyclic plastic strain values. It is observed that the influence of fatigue crack growth resistance increases with increase in cyclic strain Hardening exponent (n′) and decreases when volume fraction (Vf) or cyclic strain Hardening Coefficient (K′) increases. The present MSL theory based fatigue crack growth life prediction model is an alternative of modified rule of mixture and strengthening factor models. The predicted fatigue life for SFMMC shows good agreement with the experimental data for the low cycle and high cycle fatigue applications.
He Yang - One of the best experts on this subject based on the ideXlab platform.
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a modified johnson cook model for tensile flow behaviors of 7050 t7451 aluminum alloy at high strain rates
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Jin Qiang Tan, Mei Zhan, Shuai Liu, Tao Huang, Jing Guo, He YangAbstract:Abstract The uniaxial quasi-static and dynamic tensile tests were conducted at different strain rates (10 –3 s −1 , 800 s −1 , 1900 s −1 and 2900 s −1 ) for 7050-T7451 aluminum alloy. Then, research of the strain rate Hardening Coefficient in the original Johnson–Cook model at different strains and strain rates showed that the Coefficient is a function of strain and strain rate from the tensile experimental results. Furthermore, a modified Johnson–Cook model was proposed to describe the flow behaviors of the studied alloy based on the correction to the strain rate Hardening Coefficient. Comparisons between the experimental data and predicted results using the original JC model, Khan–Liu (KL) model and the modified JC model showed that a better agreement can be obtained applying the modified model than the other two models. Verifications for predicting three new high strain rates (1500 s −1 , 2500 s −1 and 3500 s −1 ) experimental data demonstrated the modified JC model can provide an accurate description for the dynamic behaviors of the studied alloy.
Mei Zhan - One of the best experts on this subject based on the ideXlab platform.
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a modified johnson cook model for tensile flow behaviors of 7050 t7451 aluminum alloy at high strain rates
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Jin Qiang Tan, Mei Zhan, Shuai Liu, Tao Huang, Jing Guo, He YangAbstract:Abstract The uniaxial quasi-static and dynamic tensile tests were conducted at different strain rates (10 –3 s −1 , 800 s −1 , 1900 s −1 and 2900 s −1 ) for 7050-T7451 aluminum alloy. Then, research of the strain rate Hardening Coefficient in the original Johnson–Cook model at different strains and strain rates showed that the Coefficient is a function of strain and strain rate from the tensile experimental results. Furthermore, a modified Johnson–Cook model was proposed to describe the flow behaviors of the studied alloy based on the correction to the strain rate Hardening Coefficient. Comparisons between the experimental data and predicted results using the original JC model, Khan–Liu (KL) model and the modified JC model showed that a better agreement can be obtained applying the modified model than the other two models. Verifications for predicting three new high strain rates (1500 s −1 , 2500 s −1 and 3500 s −1 ) experimental data demonstrated the modified JC model can provide an accurate description for the dynamic behaviors of the studied alloy.
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coupling effects of material properties and the bending angle on the springback angle of a titanium alloy tube during numerically controlled bending
Materials & Design, 2010Co-Authors: Zhiqiang Jiang, H Yang, Mei ZhanAbstract:Abstract The significant springback after the numerically controlled (NC) bending of a titanium alloy tube has an important influence on the precision of the shape and size of the bent tube. This springback depends on the material properties of the tube, the bending angle, and especially their coupling effects. The influence of some material properties and the bending angle on the springback angle in the NC bending of a TA18 tube were investigated using a three-dimensional (3D) elastic–plastic finite element model. Using multivariate and stepwise analyses, the coupling effects of the bending angle and the material properties on the springback angle during NC bending were revealed. It was observed that Young’s modulus, yield stress, the strain Hardening Coefficient and exponent, and the thickness anisotropy exponent, as well as interactions of these parameters with the bending angle, have a significant influence on the springback angle. The bending angle, yield stress, and Hardening Coefficient have positive effects on the springback angle, and Young’s modulus, the Hardening exponent, and the thickness anisotropy exponent have negative effects. The influence of the material properties of the titanium alloy increases with the bending angle. Young’s modulus and the strain Hardening Coefficient and exponent have the greatest influence on the springback angle. The results will be very useful in predicting, compensating for and controlling the springback of titanium alloy tubes during NC bending.
L B Zuev - One of the best experts on this subject based on the ideXlab platform.
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autowave model of crystal plasticity macro and microdefects
Crystallography Reports, 2009Co-Authors: L B Zuev, S A Barannikova, V I DanilovAbstract:A new approach to the problem of the plastic flow of solid crystals is proposed. This approach is based on studying the macroscopic localization patterns of plastic deformation, which can be considered as different types of autowave processes of defect self-organization. An unambiguous correspondence between the localization patterns and stages of plastic flow in single crystals and polycrystals is established. The propagation velocity of localized plasticity autowaves is inversely proportional to the strain-Hardening Coefficient, and the dispersion relation is quadratic. A new model is proposed to describe the development of plastic flow localization.
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localized strain autowaves at the initial stage of plastic flow in single crystals
Technical Physics, 2003Co-Authors: V I Danilov, S A Barannikova, L B ZuevAbstract:Plastic strain localization in single crystals of pure metals and alloys is studied on the yield plateau and at the easy glide stage with a zero or small strain Hardening Coefficient. The difference between localization patterns in the two cases is explained, and strain localization mechanisms are suggested. At these stages of plastic deformation, various types of autowaves are observed.
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wave phenomena in low rate plastic flow of solids
Annalen der Physik, 2001Co-Authors: L B ZuevAbstract:An investigation of plastic flow localization patterns (waves) which are ordered in space and evolve with time has been performed for a wide range of metals and alloys. These waves are found to have the following basic features: the dependence of propagation rate on work Hardening Coefficient, dispersion law and scale effect. The possibility of addressing plastic flow localization as a self-organization process occurring in a deforming medium is considered. A set of equations appropriate for the description of local flow nuclei is discussed. Consideration is given to a change-over from one local strain pattern to another in accordance with the respective stages of flow. Proposed is a model for interpreting the large-scale periodicities exhibited by the distribution of localized strain nuclei.
