Outer Cylindrical Surface Research Articles

Contact between Prefabricated Pile and Pile Clamping Jaws under Pile Driving

Pile clamping mechanism with hydraulic static pile driver has advantages of convenient for the design, improvement and use. The maximum transmission pile driving force of pile clamping mechanism of hydraulic static pile driver was analyzed. The static forces of pile clamping mechanism and prefabricated pile were researched and analyzed. The contact between prefabricated pile and pile clamping jaws under pile driving was investigated. It was revealed that when the force of pile clamping cylinder is small, the contact between prefabricated pile and pile clamping jaws under pile driving can be considered that between the elastic inner cylindrical surface and the axis parallel elastic outer cylindrical surface. When the force of pile clamping cylinder is large, the prefabricated pile contacted with pile clamping jaws under pile driving can be considered the hollow thick-wall cylinder subjected to uniformly distributed external pressure.

Simulation of Tool Contact with a Workpiece When Processing by Smoothing in the Kompas 3D Software

The paper deals with the problem of accurate determining the area of ​​contact of a tool with a workpiece in the processe of smoothing of outer cylindrical surfaces. As a tool for turning a plate were considered the standard geometry plates (SNMG). The article describes in detail the technique of simulation of contact interaction, the results of the analytical data processing.

Impedance Calculation of a Bobbin Coil in a Conductive Tube With Eccentric Walls

The complex impedance of an air-cored coil in a conductive tube with eccentric inner and outer cylindrical surfaces is calculated. The analytic expressions for the induced fields and the impedance variation due to the eddy-current flow inside the tube wall are derived using a second-order potential approach. The addition theorem of Bessel functions is employed to perform the transition between the local coordinate systems that conform to the boundaries of the structure. Although the model can be used for any coil shape and orientation, we focus our study on the configuration of a bobbin coil with axis parallel to the axes of the tube surfaces, but not necessarily coinciding with either of them. The results of the presented analysis are verified by a finite-element-method (FEM) solution.

Fully developed flow of a viscoelastic film down a vertical cylindrical or planar wall

The one-dimensional, gravity-driven film flow of a linear (l) or exponential (e) Phan-Thien and Tanner (PTT) liquid, flowing either on the outer or on the inner surface of a vertical cylinder or over a planar wall, is analyzed. Numerical solution of the governing equations is generally possible. Analytical solutions are derived only for: (1) l-PTT model in cylindrical and planar geometries in the absence of solvent, \(\beta\equiv {\tilde{\eta}_s}/\left({\tilde{\eta}_s +\tilde{\eta}_p}\right)=0\), where \(\widetilde{\eta}_p\) and \(\widetilde{\eta}_s\) are the zero-shear polymer and solvent viscosities, respectively, and the affinity parameter set at ξ = 0; (2) l-PTT or e-PTT model in a planar geometry when β = 0 and \(\xi \ne 0\); (3) e-PTT model in planar geometry when β = 0 and ξ = 0. The effect of fluid properties, cylinder radius, \(\tilde{R}\), and flow rate on the velocity profile, the stress components, and the film thickness, \(\tilde{H}\), is determined. On the other hand, the relevant dimensionless numbers, which are the Deborah, \(De={\tilde{\lambda}\tilde{U}}/{\tilde{H}}\), and Stokes, \(St=\tilde{\rho}\tilde{g}\tilde{\rm H}^{2}/\left({\tilde{\eta}_p +\tilde{\eta}_s} \right)\tilde{U}\), numbers, depend on \(\tilde{H}\) and the average film velocity, \(\widetilde{U}\). This makes necessary a trial and error procedure to obtain \(\tilde{H}\)a posteriori. We find that increasing De, ξ, or the extensibility parameter e increases shear thinning resulting in a smaller St. The Stokes number decreases as \({\tilde{R}}/{\tilde{H}}\) decreases down to zero for a film on the outer cylindrical surface, while it asymptotes to very large values when \({\tilde{R}}/{\tilde{H}}\) decreases down to unity for a film on the inner surface. When \(\xi \ne 0\), an upper limit in De exists above which a solution cannot be computed. This critical value increases with e and decreases with ξ.

Flaw detection of cylindrical surfaces in PU-packing by using machine vision technique

PU-Packing is widely used in machinery to prevent fluid from leaking. Due to the high demand for productivity and quality, bare-eye-inspection approach becomes extremely inadequate. In view of that, we developed a machine-vision-based system for detecting flaws occurred in PU-packings. The system consists of three inspection stations. The first station uses area-scan cameras to check the top and bottom surfaces of a packing. The second station uses an area-scan camera to check the interior of a packing incorporated with an infrared LED backlight. The third station uses two line-scan cameras to simultaneously scan inner and outer cylindrical surfaces of a packing. After images have been scanned, we applied variance of radius inspection method, projection method, coordinate transformation techniques, and normalized grayscale absolute difference inspection method to locate seven frequently detected defects, including deformations, burrs, interstices, scratches, blisters, air bubbles, and inclusions. The performance of the proposed system was evaluated by the accuracy, false positive rate, false negative rate and inspection time. The overall accuracy is 90.1% indicating that the proposed inspection apparatuses and methodologies are appropriate.

Magnetoelectroelastic fields in rotating multiferroic composite cylindrical structures

An analytical solution is obtained for a rotating multiferroic composite hollow cylinder made of radially polarized piezoelectric and piezomagnetic materials. Both the number of layers and the stacking sequence of the composite cylinder can be arbitrary. General mechanical, electric and magnetic boundary conditions can be applied at both the inner and outer cylindrical surfaces. The state space method is employed so that only a 2×2 matrix is involved in the whole solving procedure. In the numerical experiments, the distributions of elastic, electric as well as magnetic fields in an internally pressurized rotating BaTiO3/CoFe2O4 composite hollow cylinder subjected to different boundary conditions are presented graphically. The results clearly show that the stress fields in a multiferroic composite cylinder are controllable.

A mathematical model for cylindrical, fiber reinforced electro-pneumatic actuators

In recent years, dielectric elastomers have received increasing attention due to their unparalleled large strain actuation response (>100%). The force output, however, has remained a major limiting factor for many applications. To address this limitation, a model for a fiber reinforced dielectric elastomer actuator based on the deformation mechanism of McKibben actuators is presented. In this novel configuration, the outer cylindrical surface of a dielectric elastomer is enclosed by a network of helical fibers that are thin, flexible and inextensible. This configuration yields an axially contractile actuator, in contrast to unreinforced actuators which extend. The role of the fiber network is twofold: (i) to serve as reinforcement to improve the load-bearing capability of dielectric elastomers, and (ii) to render the actuator inextensible in the axial direction such that the only free deformation path is simultaneous radial expansion and axial contraction. In this paper, a mathematical model of the electromechanical response of fiber reinforced dielectric elastomers is derived. The model is developed within a continuum mechanics framework for large deformations. The cylindrical electro-pneumatic actuator is modeled by adapting Green and Adkins’ theory of reinforced cylinders to account for the applied electric field. Using this approach, numerical solutions are obtained assuming a Mooney–Rivlin material model. The results indicate that the relationship between the contractile force and axial shortening is bilinear within the voltage range considered. The characteristic response as a function of various system parameters such as the fiber angle, inflation pressure, and the applied voltage are reported. In this paper, the elastic portion of the modeling approach is validated using experimental data for McKibben actuators.

Unavoidable geometric errors in the side walls of end-milled parts-cylindrical surface-

The geometric characteristics of the side wall generated by the end-milling process are investigated through experiments and geometrical analyses. Both the inner and outer cylindrical surfaces are considered. Based on previous studies where the change of material removal per tooth was shown to affect the geometry of the end-milled side wall directly, it is expected that such material removal always varies just before the tool disengages the part in any case of cylindrical end-milling. The location and the size of a geometrically defected region in the cylindrical side wall are also presented. A model for predicting the depth in the radial direction is also developed. The proposed models thus make it possible to understand and anticipate the geometrical characteristics of end-milled cylindrical side walls in a quantitative manner.

An improved method of installing the blank for a drilling bit lap in the machining center

An essentially new method has been developed for installing the blank for a lap in a drilling bit for mechanical machining, which provides guaranteed gaps between the two holes with flat bottoms and the outer cylindrical surfaces of the corresponding fingers. The new method of installing the lap for machining greatly reduces the tolerances for the end and radial slack in the drilling bit and improves the working characteristics.

The Principle of Magnetic Abrasive Finishing under Rotating Electromagnetic Field and Its Application in Surface Finishing of Heavy Crankshaft

Magnetic abrasive finishing (MAF) is a processing technology using magnetic abrasive grain (MAG) under magnetic field to finish surface of workpiece. The magnetic fields used in MAF include permanent magnetic field and electromagnetic field. Two conditions must be taken into consideration in the finishing surface of workpiece. One is the sufficient cutting force; the other is the relative moving speed between MAG and workpiece. The principle of step-motor rotating magnetic field is used to produce rotating magnetic field (RMF) in this paper. RMF brings MAG to rotate and keeps workpiece immovable. Meanwhile, the coins vibrate within a definite angle range and reciprocate in axial direction so as to process the outer cylindrical surfaces. Yoke iron is made of two halves so that the coins for rotating magnetic field will be keyed to some section of heavy crankshaft, thus realizing cylindrical surface finishing on the heavy crankshaft. MAG are of importance to MAF . Six performance indexes related to MAG are suggested by studying on process parameters.

The dynamical Casimir effect with cylindrical waveguides

I consider the quantum electromagnetic field in a coaxial cylindrical waveguide, such that the outer cylindrical surface has a time-dependent radius. The field propagates parallel to the axis, inside the annular region between the two cylindrical surfaces. When the mechanical frequency and the thickness of the annular region are small enough, only Transverse Electromagnetic (TEM) photons may be generated by the dynamical Casimir effect. The photon emission rate is calculated in this regime, and compared with the case of parallel plates in the limit of very short distances between the two cylindrical surfaces. The proximity force approximation holds for the transition matrix elements in this limit, but the emission rate scales quadratically with the mechanical frequency, as opposed to the cubic dependence for parallel plates.

The Permeability of an Intact Granite

The permeability of intact Barre granite is determined by conducting transient hydraulic pulse tests that induce radial flow in saturated granite cylinders containing a water-filled co-axial cavity. Saturated specimens of granite are also subjected to uniform heating on the outer cylindrical surface and the permeability of the granite is measured at the termination of a heating sequence. The theoretical basis for the use of simplified analytical solutions for evaluating the decay of the pressure pulse is examined and the permeability of the granite in the pre-heating and post-heating states is inferred from the results of pulse tests. The reported investigations document one of the limited numbers of large-scale laboratory tests conducted to determine the permeability characteristics of intact granite. The results of the permeability measurements indicate the absence of any appreciable influences of micro structural alterations in the fabric of the granite due to its heating in a saturated condition, at an average temperature of 140 °Celsius.

Loudspeaker suspension for achieving very long excursion

An electromagnetic transducer such as an audio speaker employs a slotted yoke and two suspension components enabling very large excursion relative to the size of the diaphragm which results in improved low frequency output. A first suspension component includes an inner ring, flexible springs, and an outer body. The flexible springs extend through the slots of the yoke and couple the inner ring to the outer body. The inner ring, outer body, and flexible springs of the first suspension component may be of monolithic construction or they may be distinct components coupled together. The inner ring couples to the bobbin of the diaphragm assembly, and the outer body couples to the outer cylindrical surface of the yoke or to a mounting ring which is coupled to the outer cylindrical surface of the yoke. A second suspension component, such as a surround, couples the diaphragm assembly and to the mounting ring. The mounting ring and the outer body of the first suspension component are keyed and dimensioned to provide correct positioning and alignment of the inner ring. This accomplishes accurate positioning of the voice coil in both the radial and axial directions without complicated and expensive assembly equipment.

Performance enhancement of a chemical reactor utilizing flow instability

AbstractA detailed analysis has been performed for a heterogeneous photocatalytic Taylor vortex reactor that uses flow instability to recirculate fluid continually from the vicinity of the rotating inner cylindrical surface to the stationary outer cylindrical surface of an annulus. A comprehensive time accurate computation shows the different stages of flow evolution and the effects of finite length of the reactor in creating eddies, the overall effects of which shows very high efficiency of photocatalytic conversion. The physical arrangement considered is such that pollutant degradation is maximized by a combination of the Controlled Periodic Illumination (CPI) effect and the motion of fluid particles in a specific regime of centrifugal instability.© 2003 Society of Chemical Industry

Performance Enhancement of Photocatalytic Reactor Utilizing Flow Instability

A detailed analysis has been performed for a heterogeneous photocatalytic Taylor vortex reactor that uses flow instability to recirculate fluid continually from the vicinity of the rotating inner cylindrical surface (coated with catalyst) to the stationary outer cylindrical surface of an annulus. A detailed time accurate computation when the reactor is started impulsively shows the different stages of flow evolution and the effects of finite length of the reactor in creating eddies, the overall effects of which shows very high efficiency of photocatalytic conversion. The physical arrangement considered is such that pollutant degradation is maximized by a combination of the controlled periodic illumination effect and the motion of fluid particles in a specific regime of centrifugal instability. It was found out that optimum Reynolds's number is 380 as the system reaches steady state faster, number of vortices per unit length is more, vortices move faster towards center from end, and the magnitude of both axial and radial component of velocity is more than at higher or lower value of Reynolds's number.

A Taylor Vortex Photocatalytic Reactor for Water Purification

A detailed analysis has been performed for a heterogeneous photocatalytic Taylor vortex reactor that uses flow instability to recirculate fluid continually from the vicinity of the rotating inner cylindrical surface to the stationary outer cylindrical surface of an annulus. In the present research, a detailed time-accurate computation shows the different stages of flow evolution and the effects of the finite length of the reactor in creating eddies, which results in a very high overall efficiency of photocatalytic conversion. The physical arrangement considered is such that pollutant degradation is maximized by the motion of fluid particles in a specific regime of centrifugal instability. Also provided are detailed flow structures for the chosen parameters when the reactor is started impulsively.

Tubular MFI zeolite membranes made by secondary (seeded) growth

Zeolite MFI membranes with thickness 15–20 μm were grown on the surface of macroporous α-alumina and stainless steel support tubes (pore size 200 and 500 nm, respectively) by the secondary (seeded) growth technique. The tubular supports were dipped vertically in an aqueous suspension of colloidal silicalite-1 seed crystals (particle size 100 nm) and withdrawn at a speed of 1–2 cm/h to allow for uniform formation of seed layers on the outer (for stainless steel) or inner (for α-alumina) cylindrical surface of the support tubes. The seeded tubes were treated hydrothermally with clear solutions of different composition and the resulting MFI membranes were characterized by SEM and permeation of butane isomers. For the best preparations, binary n-butane/isobutane ratios at 22°C were as high as 28 and 53 for stainless steel and α-alumina tubes, respectively, while the n-butane permeation flux varied in the range 0.8–3.8 mmol m −2 s −1. The effect of temperature and feed partial pressure on permeation flux was also studied for binary mixtures of butane isomers and was found similar to that of planar membranes developed previously on α-alumina support disks by the same synthesis procedure.

Optimation of PGNAA instrument design for cement raw materials using the MCNP code

A simulation study of a PGNAA measuring arrangement with a252Cf neutron source for the characterization of cement raw materials was carried out using the MCNP code to investigate the effect on the system response of varying the bulk density ρ and the water contentvw of samples of fixed dry composition. The source is placed at the centre of a lead cylinder of extemal radiusRPb. This cylinder is enclosed in a coaxial cylinder of polyethylene moderator of extermal radiusRin. The sample material is confined to the space between an outer cylindrical surface of radiusRout and the moderator cylinder. The first series of simulation runs was carried out for different sets of values ofRin,Rout and ρ, and constantvw. The system specific responseS (count rate per wt%) shows a broad maximum aroundTM=Rin-RPb=4 cm andTS=Rout-Rin=8.5 cm and a dependence on ρ that is almost linear in the region of the maximum. In a second series of runs the dependence ofS onvw was studied for a geometry corresponding to a real experiment described elsewhere and for a geometry for which the density saturation effect is already apparent. It is shown that when the sensitivity of the system is optimized both ρ andvw must be used as calibration parameters while in the low-sensitivity design regionvw can be used as the only calibration parameter.

Strength analysis and optimization for both the cylinder and the anvil of a BELT-type ultra-high-pressure apparatus by FEM

BELT-type ultra-high-pressure apparatus has been used widely to synthesize diamond and CBN. Because of the critical service conditions in the chamber (6 GPa pressure and 1500°C temperature), cracks are very likely to appear in both the cylinder and the anvil of the BELT, resulting in a short working life. FEM-analysis models of both the cylinder and the anvil are presented, which have been verified by comparison of the press tonnage between practice and models. In accordance with the FEM-analysis results, the maximum principal stress within the cylinder is either the maximum axial stress near to the outer surface or the maximum tangential stress near to the inner surface, depending on the magnitude of the pre-stress acting on the outer cylindrical surface by shrink rings. It is the maximum principal stress which causes the brittle failure of the cylinder. The function of the shrink rings is of double character: the positive side is that they can decrease greatly the maximum tangential stress, whilst the negative side is that they can increase slightly the maximum axial stress. The influence of the shrink rings on the anvil is limited. It is the ultra-high compressive stress which causes the failure of the anvil. The influence of thermal stress on both the cylinder and the anvil is limited. An optimization method is presented also, by means of which the maximum axial stress within the cylinder can be decreased by about 46%, therefore enabling the working life of the BELT to be extended greatly.

Analyses of slice compression tests for aligned ceramic matrix composites—II. Type II boundary condition

Slice compression tests performed on aligned ceramic matrix composites have been analyzed. A composite cylinder has been adopted to model the composite. Analytical solutions have previously been obtained using Type I boundary condition, in which the outer cylindrical surface of the composite cylinder is assumed to be free. This boundary condition represents a lower bound constraint for the composite cylinder during interfacial debonding. An upper bound constraint, i.e. Type II boundary condition, is adopted in the present study to reanalyze slice compression tests. Limitations exist for Type I and II boundary conditions, and for the existing methodology in evaluating interfacial properties. Hence, a more realistic constraint, i.e. Type III boundary condition, and alternate methodology are also proposed.