The traction of a new aviation lubricating oil was measured on a self-made test rig. The calculating formulae of the rheological parameters of the oil such as Erying stress, limiting shear stress and shear elastic mod...The traction of a new aviation lubricating oil was measured on a self-made test rig. The calculating formulae of the rheological parameters of the oil such as Erying stress, limiting shear stress and shear elastic modulus were obtained under the condition of the high shear strain rate in elastohydrodynamic lubrication（EHL）. The constitutive equation of this oil was determined and verified by test. The results of experiments show that the behavior of the new aviation lubricating oil behaves as visco-elastic fluid and the theoretical value agrees fairly well with the measured data, which implies that the constitutive equation of this oil is correct and feasible.展开更多
Steady state rheological behavior of semi-solid ZK60-RE magnesium alloy during compression was studied. The alloy was prepared from ZK60 alloy and RE elements by casting, equal channel angular extruding, and liquidus ...Steady state rheological behavior of semi-solid ZK60-RE magnesium alloy during compression was studied. The alloy was prepared from ZK60 alloy and RE elements by casting, equal channel angular extruding, and liquidus forging. Semi-solid isothermal pre-treatment was carried out to make the grains spherical before compression. The apparent viscosity increases with decreasing the solid content and shear rate. Another very important factor is the grain size. When the solid content is high, the viscosity increases with decreasing the grain size at high strain rates and decreases with decreasing the grain size at low shear rates. Several fitting equations were obtained by using the power law equation, and the method of time-temperature superposition was used to get more information through a small number of experimental data.展开更多
In accordance with the memory function of Gaussian chain constraints in entangled polymermelts a set of material functions related to a certain"test flow"are formulated from the O-W-Ftype constitutive equati...In accordance with the memory function of Gaussian chain constraints in entangled polymermelts a set of material functions related to a certain"test flow"are formulated from the O-W-Ftype constitutive equation by the appropriate selection of the Cauchy-Green and Finger tensors.Thedependences of these material functions on the strain rate and the dependences of the linearviscoelastic functions on the primary molecular weight distribution and the entanglement sites sequencedistribution on polymer chain are derived from a multiple-entanglement model and a couple of mech-anisms of relaxation for the loop and terminal entanglement sites.When the primary polymer chainsare modelled with the Lansing-Kraemer molecular distribution function,a set of new relationshipsamong linear viscoelastic functions(η<sub>0</sub>,ψ<sub>10</sub><sup>0</sup>,η<sub>ext</sub><sup>0</sup> and τ<sub>1</sub>)and the molecular weights and their distributionare formulated.These functions and relationships are verified with experimental data.展开更多
The objective of this work is to verify the rheological behavior of irradiated [Me3NC2H4OH]+[Zn2Cl5]-and [Me3NC2H4OH]+[Zn3Cl7]-ionic liquids in comparison to the unirradiated ones,the viscosities were measured by a st...The objective of this work is to verify the rheological behavior of irradiated [Me3NC2H4OH]+[Zn2Cl5]-and [Me3NC2H4OH]+[Zn3Cl7]-ionic liquids in comparison to the unirradiated ones,the viscosities were measured by a strain-control experiment under different irradiation doses' samples(0,10,20,50,100 kGy) at different shear rates and temperatures.The curves of shear stress against shear rate present that the viscosity of ionic liquid is insensitive to shear rate;the viscosity of ionic liquids decreases with increasing temperature,and can be fitted by Arrhenius equation very well.Gamma radiation causes a decrease of viscosity of [Me3NC2H4OH]+[Zn3Cl7]-by greater than 10%,but it does not impair the viscosity of [Me3NC2H4OH]+[Zn2Cl5]-(within the experimental error) except 20 kGy irradiated sample.The results show that the radiation stability of [Me3NC2H4OH]+[Zn2Cl5]-is higher than that of [Me3NC2H4OH]+[Zn3Cl7]-.展开更多
The stress-strain relation for cast low alloy carbon steel at solidification temperature has been examined by the authors' own desingned apparatus for rheological properties measurement.The rheology model,the stre...The stress-strain relation for cast low alloy carbon steel at solidification temperature has been examined by the authors' own desingned apparatus for rheological properties measurement.The rheology model,the stress-strain constitutive equation and the rheological parameters therefrom of the cast steel were proposed.Thus the theoretical basis and calcula- ting data for computerized s#nulation on the stress-strain relation and thermal cracking of the cast steel were suggested.展开更多
Limitation and deficiency of main thcoogical models at present are descrital and analyzed, and seteralgeneral rheological models are discussed and compared with each other, and basic demands for a general model aresum...Limitation and deficiency of main thcoogical models at present are descrital and analyzed, and seteralgeneral rheological models are discussed and compared with each other, and basic demands for a general model aresummarized. The constitutive eqUation is proposetl for a new general theobocal model. The general medel feaaressimple structure and wide coverage, and can take the Place of many edsting thcofogical ed. The whel has suc-cessfully been used for Elastohydrodynamic lubrication calculation.展开更多
The work principle of flat-plate structure under shearing mode is expounded based on a vertical type rheometer for MRF which combined data acquisition with treatment and result display.The formula to calculate shearin...The work principle of flat-plate structure under shearing mode is expounded based on a vertical type rheometer for MRF which combined data acquisition with treatment and result display.The formula to calculate shearing stress is deduced.Based on different recipe for MRF,experiments under different working gap length were done by altering the intensity of magnetic field.The rheological model for MRF was established and the relationships between shearing stress,viscosity and magnetic field intensity were deduced.Experiments indicate that MRF has the flowing characters:with an increase of the magnetic induction and the nominal shear rate,the shear stress of MRF increases.However,as the working gap decreases,the shear stress increases.MRF has shear thinning property under magnetic field.展开更多
基金This project is supported by National Key Projects of China(MKPT-2001-004).
文摘The traction of a new aviation lubricating oil was measured on a self-made test rig. The calculating formulae of the rheological parameters of the oil such as Erying stress, limiting shear stress and shear elastic modulus were obtained under the condition of the high shear strain rate in elastohydrodynamic lubrication（EHL）. The constitutive equation of this oil was determined and verified by test. The results of experiments show that the behavior of the new aviation lubricating oil behaves as visco-elastic fluid and the theoretical value agrees fairly well with the measured data, which implies that the constitutive equation of this oil is correct and feasible.
基金Projects(50475029 50605015) supported by the National Natural Science Foundation of China
文摘Steady state rheological behavior of semi-solid ZK60-RE magnesium alloy during compression was studied. The alloy was prepared from ZK60 alloy and RE elements by casting, equal channel angular extruding, and liquidus forging. Semi-solid isothermal pre-treatment was carried out to make the grains spherical before compression. The apparent viscosity increases with decreasing the solid content and shear rate. Another very important factor is the grain size. When the solid content is high, the viscosity increases with decreasing the grain size at high strain rates and decreases with decreasing the grain size at low shear rates. Several fitting equations were obtained by using the power law equation, and the method of time-temperature superposition was used to get more information through a small number of experimental data.
文摘In accordance with the memory function of Gaussian chain constraints in entangled polymermelts a set of material functions related to a certain"test flow"are formulated from the O-W-Ftype constitutive equation by the appropriate selection of the Cauchy-Green and Finger tensors.Thedependences of these material functions on the strain rate and the dependences of the linearviscoelastic functions on the primary molecular weight distribution and the entanglement sites sequencedistribution on polymer chain are derived from a multiple-entanglement model and a couple of mech-anisms of relaxation for the loop and terminal entanglement sites.When the primary polymer chainsare modelled with the Lansing-Kraemer molecular distribution function,a set of new relationshipsamong linear viscoelastic functions(η<sub>0</sub>,ψ<sub>10</sub><sup>0</sup>,η<sub>ext</sub><sup>0</sup> and τ<sub>1</sub>)and the molecular weights and their distributionare formulated.These functions and relationships are verified with experimental data.
基金Project(26120231) supported by the "Hundred Talents" project of the Chinese Academy of Science
文摘The objective of this work is to verify the rheological behavior of irradiated [Me3NC2H4OH]+[Zn2Cl5]-and [Me3NC2H4OH]+[Zn3Cl7]-ionic liquids in comparison to the unirradiated ones,the viscosities were measured by a strain-control experiment under different irradiation doses' samples(0,10,20,50,100 kGy) at different shear rates and temperatures.The curves of shear stress against shear rate present that the viscosity of ionic liquid is insensitive to shear rate;the viscosity of ionic liquids decreases with increasing temperature,and can be fitted by Arrhenius equation very well.Gamma radiation causes a decrease of viscosity of [Me3NC2H4OH]+[Zn3Cl7]-by greater than 10%,but it does not impair the viscosity of [Me3NC2H4OH]+[Zn2Cl5]-(within the experimental error) except 20 kGy irradiated sample.The results show that the radiation stability of [Me3NC2H4OH]+[Zn2Cl5]-is higher than that of [Me3NC2H4OH]+[Zn3Cl7]-.
文摘The stress-strain relation for cast low alloy carbon steel at solidification temperature has been examined by the authors' own desingned apparatus for rheological properties measurement.The rheology model,the stress-strain constitutive equation and the rheological parameters therefrom of the cast steel were proposed.Thus the theoretical basis and calcula- ting data for computerized s#nulation on the stress-strain relation and thermal cracking of the cast steel were suggested.
文摘Limitation and deficiency of main thcoogical models at present are descrital and analyzed, and seteralgeneral rheological models are discussed and compared with each other, and basic demands for a general model aresummarized. The constitutive eqUation is proposetl for a new general theobocal model. The general medel feaaressimple structure and wide coverage, and can take the Place of many edsting thcofogical ed. The whel has suc-cessfully been used for Elastohydrodynamic lubrication calculation.
基金Projects(10472134,50490274) supported by the National Natural Science Foundation of China
文摘The work principle of flat-plate structure under shearing mode is expounded based on a vertical type rheometer for MRF which combined data acquisition with treatment and result display.The formula to calculate shearing stress is deduced.Based on different recipe for MRF,experiments under different working gap length were done by altering the intensity of magnetic field.The rheological model for MRF was established and the relationships between shearing stress,viscosity and magnetic field intensity were deduced.Experiments indicate that MRF has the flowing characters:with an increase of the magnetic induction and the nominal shear rate,the shear stress of MRF increases.However,as the working gap decreases,the shear stress increases.MRF has shear thinning property under magnetic field.
