Different Ratio Of Radius Research Articles

Experimental evaluation of the curves of maximal ductility and fluidity for titanium alloys in hot torsion testing

The purpose of this work is to clarify the temperature-deformation modes of extrusion pipes of titanium alloys (VT1-0, PT-7M, VT-14, VT-15, TS-5 and TS-6) and to determine the regression coefficients of the Hansel-Spittel equation by investigating plasticity and the deformation resistance during hot rotation of the specimens. This method using the torque, obtained at test procedures, makes it possible to get a complete picture of the metal flow developing in conditions of prevailing shear deformation. The shear strain, calculated from torque curves, is used as an indicator of transition to plastic area and consequent failure The hot-torsion tests were performed on a testing machine SMEG-10Т (torsion machine of the horizontal type with a maximum torque 100 Nm, equipped with a heating chamber). The temperature of the samples during the tests was in range of 800…1250 oС. Presented in this work results of hot-torsion experiments and its statistical processing are aimed to determine the regression coefficients of Hansel-Spittel equation which can be applied to calculation of parameters of seamless tubes extrusion for studied titanium alloys. Using specimens with a different ratio of radius to the length of the working part, were obtained the range of the strain rates from 6 to 25 s–1. The sensibility to strain rate at hot deformation was studied. It was found that it falls at temperatures of maximal duration of ductile behavior for majority of studied titanium alloys, excepting VT15 and PT7-M. The main results of the study should be considered experimentally determined curves of the torque dependence on the angle of rotation of the sample to change the resistance of deformation of the metal, which allowed to clarify the temperature interval of maximum ductility during pressure treatment for alloys VT1-0, PT-7M, VT-14, VT-15, TS-5 and TS-6.

Effect of Convergent and Divergent Boundaries on Flow Resistance through Porous Media

An experimental investigation on the effect of convergent and divergent streamlines on the total energy loss in the porous medium and the effect on linear parameter, a, and non-linear parameter, b, for different ratios of radii of the test section was studied in a convergent and divergent permeameter. This paper presents the results of applying dimensional analysis to obtain a relationship between friction factor (fd) and Reynolds number (Rd) for flow in porous media with convergent and divergent boundaries, using pore size of the media (d) as characteristic length. Using friction factor (fd) and Reynolds number (Rd) relationship, theoretical curves, are developed and verified with the help of existing experimental data. In the present case, Mc Corquodale data of size 1.66 cm was used as media and water as fluid, to develop curves relating friction factor (fd) and Reynolds number (Rd) for different ratios of radii of the test section of convergent permeameter and divergent permeameter with the same convergent and divergent angle of 0.328 rad.

Wave Characteristics in Magneto-electro-elastic Functionally Graded Spherical Curved Plates

Piezoelectric-piezomagnetic functionally graded materials (FGM), with a gradual change of the mechanical, electric and magnetic properties, have great promise for different applications. Based on the Legendre orthogonal polynomial series expansion approach, a dynamic solution is presented for the propagation of harmonic waves in piezoelectric-piezomagnetic FGM spherical curved plates. The material properties are assumed to vary in the direction of the thickness according to a known variation law. The dispersion curves of the piezoelectric-piezomagnetic FGM spherical curved plate and the corresponding non-piezoelectric, non-piezomagnetic plates are calculated to show the influences of the piezoelectricity and piezomagnetism. Electric potential and magnetic potential distributions are also obtained to illustrate the different influences of the piezoelectricity and piezomagnetism. Finally, a spherical curved plate at different ratio of radius to thickness is calculated to show the influence f the ratio on the piezoelectric effect and piezomagnetic effect.

Generalized thermoelastic waves in spherical curved plates without energy dissipation

In this article, the propagation of thermoelastic waves in orthotropic spherical curved plates subjected to stress-free, isothermal boundary conditions is investigated in the context of the Green–Naghdi (GN) generalized thermoelastic theory (without energy dissipation). The theoretical formulation is based on the linear GN thermoelastic theory. The coupled wave equation and heat conduction equation expressed by the displacement and temperature are obtained. By the Legendre orthogonal polynomial series expansion approach, the coupled controlling equations are solved. The convergence of the method is demonstrated through a numerical example. The dispersion curves of thermal modes and elastic modes are illustrated simultaneously. Dispersion curves of the corresponding purely elastic spherical plate are also shown to analyze the influence of thermoelasticity on elastic modes. The displacement, temperature and stress distributions of both elastic modes and thermal modes are calculated to show their differences. A thermoelastic spherical plate with a different ratio of radius to thickness is considered to show the influence of the ratio on the characteristics of thermoelastic waves.

Circumferential thermoelastic waves in orthotropic cylindrical curved plates without energy dissipation

In this article, the propagation of guided thermoelastic waves in the circumferential direction of orthotropic cylindrical curved plates subjected to stress-free, isothermal boundary conditions is investigated in the context of the Green–Naghdi (GN) generalized thermoelastic theory (without energy dissipation). The coupled wave equations and heat conduction equation are solved by the Legendre orthogonal polynomial series expansion approach. The convergency of the method is discussed through a numerical example. The dispersion curves of thermal modes and elastic modes are illustrated simultaneously. Dispersion curves of the corresponding pure elastic cylindrical plate are also shown to analyze the influence of the thermoelasticity on elastic modes. The displacement, temperature and stress distributions are shown to discuss the differences between the elastic modes and thermal modes. A thermoelastic cylindrical plate with a different ratio of radius to thickness is considered to discuss the influence of the ratio on the characteristics of circumferential thermoelastic waves.

Circumferential wave in magneto-electro-elastic functionally graded cylindrical curved plates

Piezoelectric-piezomagnetic functionally graded materials (FGM), with a gradual change of the mechanical and electromagnetic properties, have greatly applying promises. Based on Legendre orthogonal polynomial series expansion approach, a dynamic solution is presented for the propagation of circumferential harmonic waves in piezoelectric-piezomagnetic FGM cylindrical curved plates. The materials properties are assumed to vary in the direction of the thickness according to a known variation law. The dispersion curves of the piezoelectric-piezomagnetic FGM cylindrical curved plate and the corresponding non-piezoelectric and non-piezomagnetic cylindrical curved plates are calculated to show the influences of the piezoelectricity and piezomagnetism. Electric potential and magnetic potential distributions are also obtained to illustrate the different influences of the piezoelectricity and piezomagnetism. Finally, a cylindrical curved plate at a different ratio of radius to thickness is calculated to show the influence of the ratio on the piezoelectric effect and piezomagnetic effect.

Wave propagation in non-homogeneous magneto-electro-elastic hollow cylinders

A dynamic solution is presented for the propagation of harmonic waves in imhomogeneous (functionally graded) magneto-electro-elastic hollow cylinders composed of piezoelectric BaTiO 3 and magnetostrictive CoFe 2O 4. The materials properties are assumed to vary in the direction of the thickness according to a known variation law. The Legendre orthogonal polynomial series expansion approach is employed to determine the wave propagating characteristics in the hollow cylinders. The dispersion curves of the imhomogeneous piezoelectric–piezomagnetic hollow cylinder and the corresponding non-piezoelectric and non-piezomagnetic hollow cylinders are calculated to show the influence of the piezoelectricity and piezomagnetism. Electric potential and magnetic potential distributions are obtained to illustrate the different influences of the piezoelectricity and piezomagnetism and the different influences of the piezoelectric effect and piezomagnetic effect on longitudinal modes and torsional modes. For the radial polarizing piezoelectric–piezomagnetic hollow cylinder, the piezoelectric effect and piezomagnetic effect take mostly on the longitudinal mode. Finally, a hollow cylinder at different ratio of radius to thickness is calculated to show the influence of the ratio on the piezoelectric effect and piezomagnetic effect.

EFFICIENCY OF STEADY NON-UNIFORM FLOW THROUGH HOMOGENEOUS POROUS MEDIA

ABSTRACT An experimental investigation on the effect of convergent flow on the linear and non-linear parameters for different ratios of radii of the test section in a converging permeameter was studied. The relationship relating friction factor and Reynolds number using the square root of intrinsic permeability as the characteristic length is examined for flow in porous media with converging boundaries. Using the friction factor (fk) and Reynolds number (Rk) relationship, theoretical curves, which are similar to a Moody diagram used for pipe flow are developed and verified with the help of existing experimental data. In the present case, crushed rock of size 4.73 mm was used as media and water as fluid, to develop curves relating friction factor and Reynolds number with efficiency for different rate of flows of the test section of permeameter.

Effect of Convergence on Nonlinear Flow in Porous Media

The behavior of flow through porous media has been the subject of study for a long time. The relationship relating friction factor and Reynolds number using the square root of intrinsic permeability as the characteristic length is examined for flow in porous media with converging boundaries. An experimental investigation of the effect of convergence of streamlines on the linear and nonlinear parameters for different radial flow lines in a converging permeameter for different ratios of radii of the test section is also studied. In the present case, crushed rocks of sizes 11.64 and 4.73 mm were used as media and water as fluid, to develop curves relating friction factor and Reynolds number for different radial flow lines with different ratios of radii of the test section of the permeameter.