The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform
A Meyers - One of the best experts on this subject based on the ideXlab platform.
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new results for the spin of the eulerian triad and the Logarithmic spin and Rate
Acta Mechanica, 2002Co-Authors: O. T. Bruhns, H. Xiao, A MeyersAbstract:A new basis-free expression is derived for the Logarithmic spin tensor, which assumes a unified form for all the three cases of coalescence of the three eigenvalues of the left Cauchy-Green deformation tensorB. It is shown that this new expression is endowed with particular continuity properties, i.e., each of its coefficients either accompanies the vanishing of its associated term or remains valid whenever the eigenvalues ofB become repeated. These favorable properties, which are not enjoyed by the expressions derived earlier, result in the foregoing unified form of expression which could not be achieved by means of the previous expressions. At the same time, a fully explicit, basis-free expression is obtained for the spin tensor of the Eulerian triad, which is expressed straightforwardly in terms of the three basic invariants ofB and hence renders computations of the eigenvalues ofB unnecessary. Moreover, remarks are given towards explaining and clarifying some issues concerning the hypo-elastic equation of grade zero with the Logarithmic Rate, including the exact integrability and unstable stress responses associated with initial shear stresses at simple shear deformations, etc.
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large simple shear and torsion problems in kinematic hardening elasto plasticity with Logarithmic Rate
International Journal of Solids and Structures, 2001Co-Authors: Otto T Bruhns, H. Xiao, A MeyersAbstract:Abstract Large simple shear and torsion problems in plasticity have been the object of a large number of papers. Sophisticated schemes have been developed (e.g. J. Appl. Mech. 50 (1983) 561) that overcome problems encountered (cf. e.g. J. Mech. Phys. Solids 48 (2000) 2231; Int. J. Solids Struct. 37 (2000) 5037). This paper substantially uses the Logarithmic Rate (Acta Mechanica 124 (1997a) 89), which is equally based on strong mathematical and physical principles and therefore may contrast to classical approaches of cited kinds. Stress responses to large simple shear and torsional deformations in elastoplastic bodies are studied by applying the self-consistent kinematic hardening J 2 -flow model based on the Logarithmic tensor Rate, recently established by these authors (Int. J. Plasticity 15 (1999) 479). The application of the Logarithmic stress Rate in the elastic Rate equation of hypoelastic type results in an exact finite hyperelastic solution in terms of Hencky's Logarithmic strain. The plastic solution is composed of two parts: the back stress and the effective stress (the Kirchhoff stress reduced by the back stress). It is shown that the evolution equation of the back stress with the Logarithmic Rate is integrable to deliver a closed-form relation between the back stress and Hencky's Logarithmic strain and the current stress. Moreover, the effective stress is shown to be governed by a first-order nonlinear ordinary differential equation with a small dimensionless material parameter multiplying the highest derivative, for which the initial condition is related to the elastic–plastic transition and prescribed in terms of the just-mentioned small parameter. A singular perturbation solution for the just-mentioned equation is derived by utilizing the method of matched expansions. With the analytical solution derived, it is possible to make a detailed study of the coupling effect of material properties, including the elastic, yielding and hardening properties, on elastic–plastic responses. For the large deformations at issue, it is demonstRated that, merely with three commonly known classical material constants, i.e., the elastic shear modulus, the initial tensile yield stress and the hardening modulus, the simple kinematic hardening J 2 -flow model with the Logarithmic Rate may supply satisfactory explanations for salient features of complex behaviour in experimental observation.
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Large-strain response of isotropic-hardening elastoplasticity with Logarithmic Rate: Swift effect in torsion
Archive of Applied Mechanics, 2001Co-Authors: O. T. Bruhns, H. Xiao, A MeyersAbstract:Recently, a new Eulerian Rate-type isotropic-hardening elastoplasticity model has been established by utilizing the newly discovered Logarithmic Rate. It has been proved that this model is unique among all isotropic hardening elastoplastic models with all possible objective corotational stress Rates and other known objective stress Rates by virtue of the self-consistency criterion: the hypoelastic formulation intended for elastic behaviour must be exactly integrable to deliver a hyperelastic relation. The simple shear response of this model has been studied and shown to be reasonable for both the shear and normal stress components. The objective of this work is to further study the large deformation response of this model, in particular, the second-order effects, including the well-known Swift effect, in torsion of thin-walled cylindrical tubes with free ends. An analytical perturbation solution is derived, and numerical results are presented by means of the Runge–Kutta method. It is shown that the prediction of this model for the shear stress is in good accord with experimental data, but the predicted axial length change is negligibly small and much less than experimental data. This suggests that the strain-induced anisotropy may be the main cause of the Swift effect.
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large strain responses of elastic perfect plasticity and kinematic hardening plasticity with the Logarithmic Rate swift effect in torsion
International Journal of Plasticity, 2001Co-Authors: H. Xiao, Otto T Bruhns, A MeyersAbstract:Abstract A new Eulerian Rate type elastic-perfectly plastic model has recently been established by utilizing the newly discovered Logarithmic Rate. It has been proved that this model is unique among the objective elastic-perfectly plastic models with all objective corotational stress Rates and other known objective stress Rates by virtue of the self-consistency criterion: the hypoelastic formulation intended for elastic behaviour must be exactly integrable to deliver a hyperelastic relation. The finite simple shear response of this model has been studied and shown to be reasonable for both shear and normal stress components. On the other hand, a kinematic hardening plasticity model may be formulated by adopting the Logarithmic Rate. The objective of this work is to further study the large deformation responses of the foregoing two kinds of idealized models, in particular the well-known Swift effect, in torsion of thin-walled cylindrical tubes. A complete, rigorous analysis is made for the orders of magnitude of all stress components. A closed-form solution is obtained for the kinematic hardening plastic case, and an analytical perturbation solution is derived for the elastic-perfectly plastic case. It is shown that the simple idealized kinematic hardening model with the Logarithmic Rate, which uses only two classical material constants, i.e., the initial (tensile) yield stress and the hardening modulus, may arrive at satisfactory explanation for and reasonable accord with salient features of experimental observation.
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The choice of objective Rates in finite elastoplasticity: general results on the uniqueness of the Logarithmic Rate
Proceedings of the Royal Society of London. Series A: Mathematical Physical and Engineering Sciences, 2000Co-Authors: Heng Xiao, O. T. Bruhns, A MeyersAbstract:A Eulerian Rate formulation of finite elastoplasticity is a composite one composed of a Rate equation for elastic behaviour and a flow rule for plastic behaviour as well as an evolution equation for hardening behaviour, in which objective Eulerian tensor Rates are used. Among a large variety of objective Rates (actually infinitely many), how to choose suitable ones has been one of the crucial points in finite elastoplasticity. It is realized that the foregoing composite formulation of elastoplasticity should fulfil certain consistency criteria in order to avoid inconsistencies or contradictions. These criteria narrow the choice of objective Rates. These authors (Bruhns and co–workers and Xiao and co–workers) have recently introduced the self–consistency criterion : in a composite formulation of elastoplasticity, the Rate equation intended for characterization of elastic behaviour should be exactly integrable to deliver an elastic relation. It has been demonstRated in the work of the aforementioned authors that if a composite formulation of elastoplasticity with objective Rates is required to fulfil the just–stated self–consistency criterion, as it should be, then the newly discovered Logarithmic Rate is the only possible choice among all objective corotational Rates, including the Zaremba–Jaumann Rate and the Green–Naghdi Rate, etc. In the afore–mentioned result, non–corotational Rates, including Oldroyd Rates, Cotter–Rivlin Rate and Truesdell Rate, etc., are not taken into consideration in general. It is the main goal of this paper to further establish the uniqueness of the Logarithmic Rate among all corotational and non–corotational objective Rates. Essential to the attainment of this goal is the use of the yielding–stationarity criterion : the vanishing of the stress Rate implies that the yield function is stationary. It is shown that the just–stated criterion is necessary for a composite Eulerian Rate formulation of finite elastoplasticity to be consistent and means that the stress Rate must be a corotational Rate. The main goal of this article is, thus, attained by combining the just–stated result and the established result stated before.
T R Mankhand - One of the best experts on this subject based on the ideXlab platform.
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hydrometallurgical processing of spent lithium ion batteries libs in the presence of a reducing agent with emphasis on kinetics of leaching
Chemical Engineering Journal, 2015Co-Authors: Pratima Meshram, B D Pandey, T R MankhandAbstract:Abstract In this study, sulfuric acid leaching was applied to recover lithium, cobalt, nickel and manganese from the cathodic active material of spent LIBs in presence of a reducing agent, sodium bisulfite. The conditions for the dissolution of valuable metals were optimized while varying the parameters such as acid concentration, leaching time, temperature and pulp density. It was found that with 1 M H2SO4 and 0.075 M NaHSO3 as reducing agent ∼96.7% Li, 91.6% Co, 96.4% Ni and 87.9% Mn were recovered in 4 h at 368 K and a pulp density of 20 g/L. Kinetic data for the dissolution of the metals such as Li, Co and Ni in the temperature range 308–368 K showed best fit to the kinetic model governed by the empirical Logarithmic Rate law. Leaching of the metals proceeded through the diffusion of lixiviant on the surface of the substRate particles, which was corroboRated by XRD phase analyses and SEM–EDS of the untreated sample and the leach residues. From the leach liquor, >98% Co was recovered as cobalt oxalate (CoC2O4·2H2O) by precipitation with oxalic acid. MnCO3, NiCO3 and Li2CO3 were precipitated from the cobalt depleted solution. By this process, high recovery of Li and Co could be achieved in the solution and then in the form of carbonate and oxalate, respectively along with the recovery of Mn and Ni as their carbonates.
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recovery of valuable metals from cathodic active material of spent lithium ion batteries leaching and kinetic aspects
Waste Management, 2015Co-Authors: Pratima Meshram, B D Pandey, T R MankhandAbstract:This work is focussed on the processing of cathodic active material of spent lithium ion batteries (LIBs) to ensure resource recovery and minimize environmental degradation. The sulfuric acid leaching of metals was carried out for the recovery of all the valuable metals including nickel and manganese along with the frequently targeted metals like lithium and cobalt. The process parameters such as acid concentration, pulp density, time and temperature for the leaching of metals from the cathode powder containing 35.8% Co, 6.5% Li, 11.6% Mn and 10.06% Ni, were optimized. Results show the optimized leach recovery of 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn when the material was leached in 1M H2SO4 at 368 K and 50 g/L pulp density for 240 min. The need of a reductant for improved recovery of cobalt and manganese has been explained by the thermodynamic analysis (Eh-pH diagram) for these metals. Leaching of the valuable metals was found to follow the Logarithmic Rate law controlled by surface layer diffusion of the lixiviant reacting with the particles. The mode of leaching of the metals from the spent LIBs was further examined by chemical analysis of the samples at various stage of processing which was further corroboRated by characterizing the untreated sample and the leach residues by XRD phase identification and the SEM-EDS studies.
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recovery of valuable metals from cathodic active material of spent lithium ion batteries leaching and kinetic aspects
Waste Management, 2015Co-Authors: Pratima Meshram, B D Pandey, T R MankhandAbstract:Abstract This work is focussed on the processing of cathodic active material of spent lithium ion batteries (LIBs) to ensure resource recovery and minimize environmental degradation. The sulfuric acid leaching of metals was carried out for the recovery of all the valuable metals including nickel and manganese along with the frequently targeted metals like lithium and cobalt. The process parameters such as acid concentration, pulp density, time and temperature for the leaching of metals from the cathode powder containing 35.8% Co, 6.5% Li, 11.6% Mn and 10.06% Ni, were optimized. Results show the optimized leach recovery of 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn when the material was leached in 1 M H 2 SO 4 at 368 K and 50 g/L pulp density for 240 min. The need of a reductant for improved recovery of cobalt and manganese has been explained by the thermodynamic analysis (Eh–pH diagram) for these metals. Leaching of the valuable metals was found to follow the Logarithmic Rate law controlled by surface layer diffusion of the lixiviant reacting with the particles. The mode of leaching of the metals from the spent LIBs was further examined by chemical analysis of the samples at various stage of processing which was further corroboRated by characterizing the untreated sample and the leach residues by XRD phase identification and the SEM-EDS studies.
Pratima Meshram - One of the best experts on this subject based on the ideXlab platform.
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hydrometallurgical processing of spent lithium ion batteries libs in the presence of a reducing agent with emphasis on kinetics of leaching
Chemical Engineering Journal, 2015Co-Authors: Pratima Meshram, B D Pandey, T R MankhandAbstract:Abstract In this study, sulfuric acid leaching was applied to recover lithium, cobalt, nickel and manganese from the cathodic active material of spent LIBs in presence of a reducing agent, sodium bisulfite. The conditions for the dissolution of valuable metals were optimized while varying the parameters such as acid concentration, leaching time, temperature and pulp density. It was found that with 1 M H2SO4 and 0.075 M NaHSO3 as reducing agent ∼96.7% Li, 91.6% Co, 96.4% Ni and 87.9% Mn were recovered in 4 h at 368 K and a pulp density of 20 g/L. Kinetic data for the dissolution of the metals such as Li, Co and Ni in the temperature range 308–368 K showed best fit to the kinetic model governed by the empirical Logarithmic Rate law. Leaching of the metals proceeded through the diffusion of lixiviant on the surface of the substRate particles, which was corroboRated by XRD phase analyses and SEM–EDS of the untreated sample and the leach residues. From the leach liquor, >98% Co was recovered as cobalt oxalate (CoC2O4·2H2O) by precipitation with oxalic acid. MnCO3, NiCO3 and Li2CO3 were precipitated from the cobalt depleted solution. By this process, high recovery of Li and Co could be achieved in the solution and then in the form of carbonate and oxalate, respectively along with the recovery of Mn and Ni as their carbonates.
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recovery of valuable metals from cathodic active material of spent lithium ion batteries leaching and kinetic aspects
Waste Management, 2015Co-Authors: Pratima Meshram, B D Pandey, T R MankhandAbstract:This work is focussed on the processing of cathodic active material of spent lithium ion batteries (LIBs) to ensure resource recovery and minimize environmental degradation. The sulfuric acid leaching of metals was carried out for the recovery of all the valuable metals including nickel and manganese along with the frequently targeted metals like lithium and cobalt. The process parameters such as acid concentration, pulp density, time and temperature for the leaching of metals from the cathode powder containing 35.8% Co, 6.5% Li, 11.6% Mn and 10.06% Ni, were optimized. Results show the optimized leach recovery of 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn when the material was leached in 1M H2SO4 at 368 K and 50 g/L pulp density for 240 min. The need of a reductant for improved recovery of cobalt and manganese has been explained by the thermodynamic analysis (Eh-pH diagram) for these metals. Leaching of the valuable metals was found to follow the Logarithmic Rate law controlled by surface layer diffusion of the lixiviant reacting with the particles. The mode of leaching of the metals from the spent LIBs was further examined by chemical analysis of the samples at various stage of processing which was further corroboRated by characterizing the untreated sample and the leach residues by XRD phase identification and the SEM-EDS studies.
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recovery of valuable metals from cathodic active material of spent lithium ion batteries leaching and kinetic aspects
Waste Management, 2015Co-Authors: Pratima Meshram, B D Pandey, T R MankhandAbstract:Abstract This work is focussed on the processing of cathodic active material of spent lithium ion batteries (LIBs) to ensure resource recovery and minimize environmental degradation. The sulfuric acid leaching of metals was carried out for the recovery of all the valuable metals including nickel and manganese along with the frequently targeted metals like lithium and cobalt. The process parameters such as acid concentration, pulp density, time and temperature for the leaching of metals from the cathode powder containing 35.8% Co, 6.5% Li, 11.6% Mn and 10.06% Ni, were optimized. Results show the optimized leach recovery of 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn when the material was leached in 1 M H 2 SO 4 at 368 K and 50 g/L pulp density for 240 min. The need of a reductant for improved recovery of cobalt and manganese has been explained by the thermodynamic analysis (Eh–pH diagram) for these metals. Leaching of the valuable metals was found to follow the Logarithmic Rate law controlled by surface layer diffusion of the lixiviant reacting with the particles. The mode of leaching of the metals from the spent LIBs was further examined by chemical analysis of the samples at various stage of processing which was further corroboRated by characterizing the untreated sample and the leach residues by XRD phase identification and the SEM-EDS studies.
Tao Zhou - One of the best experts on this subject based on the ideXlab platform.
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separation and recovery of valuable metals from spent lithium ion batteries simultaneous recovery of li and co in a single step
Separation and Purification Technology, 2019Co-Authors: Xiangping Chen, Duozhi Kang, Jiazhu Li, Tao ZhouAbstract:Abstract Sustainable recovery of metals from spent lithium-ion batteries (LIBs) may be of great significance regarding the conservation of metal resources and alleviation of potential risk towards eco-system. Herein an environmentally benign process was proposed for the recovery of high value-added metals (Co and Li) from typical waste cathode materials (LiCoO2) of spent LIBs using mild tartaric acid as both leaching and precipitating reagent. Leaching results indicate that Co and Li can be effectively sepaRated under experimental conditions of reaction temperature- 80 °C, retention time- 30 min, pulp density- 30 mL/g, reducatant dosage- 3 vol% H2O2 and acid concentration- 0.6 mol/L. After leaching, 98% Co and 97% Li can be recovered as precipitate and Li+ enriched solution, respectively. And the leaching of Co and Li fits well to Logarithmic Rate model, with apparent activation energy of 34.5 and 29.7 KJ/mol, respectively. In addition, characterization results (i.e. FT-IR, SEM-EDS and TGA-DSC) suggest that Co can be directly recovered as relatively pure cobalt tartRate (C4H4O6Co, with a purity of 96.4%) in leaching residues. This whole process can be a sustainable alternative for the simultaneous recovery of Li and Co from waste cathode materials of spent LIBs.
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Recovery of valuable metals from waste cathode materials of spent lithium-ion batteries using mild phosphoric acid
Journal of Hazardous Materials, 2017Co-Authors: Xiangping Chen, Chuanbao Luo, Hongrui Ma, Tao ZhouAbstract:Sustainable recycling of valuable metals from spent lithium-ion batteries (LIBs) may be necessary to alleviate the depletion of stRategic metal resources and potential risk of environmental pollution. Herein a hydrometallurgical process was proposed to explore the possibility for the recovery of valuable metals from the cathode materials (LiCoO2) of spent LIBs using phosphoric acid as both leaching and precipitating agent under mild leaching conditions. According to the leaching results, over 99% Co can be sepaRated and recovered as Co3(PO4)2in a short-cut process involved merely with leaching and filtrating, under the optimized leaching conditions of 40 °C (T), 60 min (t), 4 vol.% H2O2, 20 mL g−1(L/S) and 0.7 mol/L H3PO4. Then leaching kinetics was investigated based on the Logarithmic Rate kinetics model and the obtained results indicate that the leaching of Co and Li fits well with this model and the activation energies (Ea) for Co and Li are 7.3 and 10.2 kJ/mol, respectively. Finally, it can be discovered from characterization results that the obtained product is 97.1% pure cobalt phosphate (Co3(PO4)2).
H. Xiao - One of the best experts on this subject based on the ideXlab platform.
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new results for the spin of the eulerian triad and the Logarithmic spin and Rate
Acta Mechanica, 2002Co-Authors: O. T. Bruhns, H. Xiao, A MeyersAbstract:A new basis-free expression is derived for the Logarithmic spin tensor, which assumes a unified form for all the three cases of coalescence of the three eigenvalues of the left Cauchy-Green deformation tensorB. It is shown that this new expression is endowed with particular continuity properties, i.e., each of its coefficients either accompanies the vanishing of its associated term or remains valid whenever the eigenvalues ofB become repeated. These favorable properties, which are not enjoyed by the expressions derived earlier, result in the foregoing unified form of expression which could not be achieved by means of the previous expressions. At the same time, a fully explicit, basis-free expression is obtained for the spin tensor of the Eulerian triad, which is expressed straightforwardly in terms of the three basic invariants ofB and hence renders computations of the eigenvalues ofB unnecessary. Moreover, remarks are given towards explaining and clarifying some issues concerning the hypo-elastic equation of grade zero with the Logarithmic Rate, including the exact integrability and unstable stress responses associated with initial shear stresses at simple shear deformations, etc.
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large simple shear and torsion problems in kinematic hardening elasto plasticity with Logarithmic Rate
International Journal of Solids and Structures, 2001Co-Authors: Otto T Bruhns, H. Xiao, A MeyersAbstract:Abstract Large simple shear and torsion problems in plasticity have been the object of a large number of papers. Sophisticated schemes have been developed (e.g. J. Appl. Mech. 50 (1983) 561) that overcome problems encountered (cf. e.g. J. Mech. Phys. Solids 48 (2000) 2231; Int. J. Solids Struct. 37 (2000) 5037). This paper substantially uses the Logarithmic Rate (Acta Mechanica 124 (1997a) 89), which is equally based on strong mathematical and physical principles and therefore may contrast to classical approaches of cited kinds. Stress responses to large simple shear and torsional deformations in elastoplastic bodies are studied by applying the self-consistent kinematic hardening J 2 -flow model based on the Logarithmic tensor Rate, recently established by these authors (Int. J. Plasticity 15 (1999) 479). The application of the Logarithmic stress Rate in the elastic Rate equation of hypoelastic type results in an exact finite hyperelastic solution in terms of Hencky's Logarithmic strain. The plastic solution is composed of two parts: the back stress and the effective stress (the Kirchhoff stress reduced by the back stress). It is shown that the evolution equation of the back stress with the Logarithmic Rate is integrable to deliver a closed-form relation between the back stress and Hencky's Logarithmic strain and the current stress. Moreover, the effective stress is shown to be governed by a first-order nonlinear ordinary differential equation with a small dimensionless material parameter multiplying the highest derivative, for which the initial condition is related to the elastic–plastic transition and prescribed in terms of the just-mentioned small parameter. A singular perturbation solution for the just-mentioned equation is derived by utilizing the method of matched expansions. With the analytical solution derived, it is possible to make a detailed study of the coupling effect of material properties, including the elastic, yielding and hardening properties, on elastic–plastic responses. For the large deformations at issue, it is demonstRated that, merely with three commonly known classical material constants, i.e., the elastic shear modulus, the initial tensile yield stress and the hardening modulus, the simple kinematic hardening J 2 -flow model with the Logarithmic Rate may supply satisfactory explanations for salient features of complex behaviour in experimental observation.
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Large-strain response of isotropic-hardening elastoplasticity with Logarithmic Rate: Swift effect in torsion
Archive of Applied Mechanics, 2001Co-Authors: O. T. Bruhns, H. Xiao, A MeyersAbstract:Recently, a new Eulerian Rate-type isotropic-hardening elastoplasticity model has been established by utilizing the newly discovered Logarithmic Rate. It has been proved that this model is unique among all isotropic hardening elastoplastic models with all possible objective corotational stress Rates and other known objective stress Rates by virtue of the self-consistency criterion: the hypoelastic formulation intended for elastic behaviour must be exactly integrable to deliver a hyperelastic relation. The simple shear response of this model has been studied and shown to be reasonable for both the shear and normal stress components. The objective of this work is to further study the large deformation response of this model, in particular, the second-order effects, including the well-known Swift effect, in torsion of thin-walled cylindrical tubes with free ends. An analytical perturbation solution is derived, and numerical results are presented by means of the Runge–Kutta method. It is shown that the prediction of this model for the shear stress is in good accord with experimental data, but the predicted axial length change is negligibly small and much less than experimental data. This suggests that the strain-induced anisotropy may be the main cause of the Swift effect.
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large strain responses of elastic perfect plasticity and kinematic hardening plasticity with the Logarithmic Rate swift effect in torsion
International Journal of Plasticity, 2001Co-Authors: H. Xiao, Otto T Bruhns, A MeyersAbstract:Abstract A new Eulerian Rate type elastic-perfectly plastic model has recently been established by utilizing the newly discovered Logarithmic Rate. It has been proved that this model is unique among the objective elastic-perfectly plastic models with all objective corotational stress Rates and other known objective stress Rates by virtue of the self-consistency criterion: the hypoelastic formulation intended for elastic behaviour must be exactly integrable to deliver a hyperelastic relation. The finite simple shear response of this model has been studied and shown to be reasonable for both shear and normal stress components. On the other hand, a kinematic hardening plasticity model may be formulated by adopting the Logarithmic Rate. The objective of this work is to further study the large deformation responses of the foregoing two kinds of idealized models, in particular the well-known Swift effect, in torsion of thin-walled cylindrical tubes. A complete, rigorous analysis is made for the orders of magnitude of all stress components. A closed-form solution is obtained for the kinematic hardening plastic case, and an analytical perturbation solution is derived for the elastic-perfectly plastic case. It is shown that the simple idealized kinematic hardening model with the Logarithmic Rate, which uses only two classical material constants, i.e., the initial (tensile) yield stress and the hardening modulus, may arrive at satisfactory explanation for and reasonable accord with salient features of experimental observation.
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Large Strain Response of Kinematic Hardening Elastoplasticity with the Logarithmic Rate: Swift Effect in Torsion
Meccanica, 2000Co-Authors: A Meyers, O. T. Bruhns, H. XiaoAbstract:Recently, a new Eulerian Rate type kinematic hardening elastoplasticity model has been established by utilizing the newly discovered Logarithmic Rate. It has been proved that this model is unique among all the objective kinematic hardening elastoplastic models with all possible objective corotational stress Rates and other known objective stress Rates by virtue of the self-consistency criterion: the hypoelastic formulation intended for elastic behaviour must be exactly integrable to deliver a hyperelastic relation. The finite simple shear response of this model has been studied and shown to be reasonable for both shear and normal stress components. The objective of this work is to further study the large deformation response of this model, in particular the well-known Swift effect, in torsion of thin-walled cylindrical tubes with free ends. Analytical perturbation solution and numerical solution are presented for the case of linear kinematic hardening at large compressible deformation. It is shown that the prediction from the foregoing model is in good accord with experimental data reported in literature.
