Principle of torque formation with reduced pulsation in switched reluctance motor with U-shaped poles

In the paper the types of motors for vehicles and highlights the switched reluctance motor type as one that has a simple design, high reliability and low cost. The principle of operation of switched reluctance motors (SRM) and their modifications are given. However, the widespread use of SRM in vehicles is constrained by the low specific torque and its high ripple. To increase the specific torque, a paired winding of windings on adjacent rods of U-shaped stator poles is proposed. The principle of formation of rotational force is shown and the estimation of efficiency of use of the electric power for its formation is offered. The COMSOL Multiphysics software environment analyzes the advantages and disadvantages of using U-shaped poles with a trapezoidal and rectangular profile, and selected the latter because of the greater torque at the same dimensions. It is shown that the width of the pole rods with a rectangular profile to ensure maximum torque should be about a third of the width of the base of the pole. A typical form of current of the pole winding, which minimizes the pulsation of the moment, is analyzed. The expediency of designing a specialized electric drive for the proposed topology of SRM and synthesis for it of the control law, which provides the required value of the moment with minimal ripple, is substantiated. As usual, to ensure the constant moment generated by the pole in a certain sector it is necessary to form a current of near trapezoidal shape in the pole winding. As a result of the research, conclusions were made about the possibility of reducing the cost of SRM technology when using a modular structure based on U-shaped poles with paired winding at the stator poles, in which the windings are wound on the rod of two adjacent poles, which allows them to be placed compactly the use of additional space and, accordingly, provides a greater density of the poles. Modeling the process of forming the torque of the motor in the COMSOL Multiphysics software environment showed the advantages of using poles with a rectangular profile compared to trapezoidal poles and confirmed the feasibility of using poles with a rod width of about a third of the pole base width.

Effect of Forming Parameters on Profile Thinning of Flexible 3D Multi-Point Stretch Bending

The ABAQUS finite element simulation software is used to simulate the flexible multi-point three-dimensional stretch bending process of aluminum profiles. The effect of process parameters on the web thickness of rectangular profile in flexible multi-point three-dimensional stretch bending is studied by orthogonal experiment and range analysis. The process parameters used in the experiments include pre-stretching value, post-stretching value, the number of multi-point dies and friction coefficient. The optimal combination of process parameters is obtained by numerical simulation and experimental verification. When the aluminum profile is completed flexible multi-point stretch bending according to the best parameters, the thickness thinning of outer web and inner web is the smallest. The experimental result is closed to the numerical simulated results. The effectiveness of the numerical simulation is verified by the corresponding experimental methods.

Etalon for Nanometrology Produced by Anisotropic Etching

Possibilities and results of using relief structures produced by anisotropic etching as etalons for linear measurements in nanorange are discussed. Two types of the structures with different profiles and with two approaches to estimation of influence of its sophistication degree on measurement results are considered. Analyze of methods and means of measurements of its geometric parameters and comparison of uncertainness of measurement results are conducted. The important condition for diminishing the measurements uncertainness is taking into account irregularities of a sample surface. These irregularities were evaluated by TEM and CD-AFM. Results of harnessing these types of structures are different also. The bureau International des Poids et Mesures recommended the structure with rectangular profile and its attestation procedure as an example for all national committees on linewidth metrology in nanorange. The structure with trapezoid profile that induced hopes for decision of basic tasks of nanometrology in past is occurred to be poorly in demand even on national scale.

Inverse Approach for the Average Convection Coefficient Induced by a Forced Fluid Flow Over an Annular Fin of Rectangular Profile Using Tip Temperature Measurements

The objective of the present paper is to develop a simple algebraic computational procedure for the estimation of the average convection coefficient of a forced fluid flow over an annular fin of rectangular profile within the platform of inverse heat conduction problems. The data required is the tip temperatures of an annular fin of rectangular profile, which are measured in an experimental setup. Based on nonlinear regression analysis, an empirical correlation equation is constructed for the dimensionless average tip temperature depending upon the dimensionless thermo–geometrical parameter and the radius ratio. When compared against the outcome of a direct heat conduction problem, the good quality of the estimated average convection coefficient for the annular fin of rectangular profile demonstrates the feasibility of the simple algebraic computational procedure.

Plastic flow of isotropic rigid body at uniform deformation

The mathematical analysis of plastic flow processes under uniform plane, axisymmetric and volumetric deformation is carried out. The analysis is based on the external shape change of the body, which determines the movement of material points. It is shown that the plastic flow of an isotropic rigid-plastic body under plane deformation obeys the hyperbolic law, and for axisymmetric and volumetric deformations – the inverse square law. Spatial-geometric expressions of these laws made it possible to reveal and explain in a new way the physical essence of plastic shear. It is proved that the stressed state of a body under uniform tension-compression deformation is complex and cannot be defined as “linear”. The normal stress, which coincides with the direction of the resulting deformation force, is not the main one, since in the areas perpendicular to this direction, the shear stresses are not equal to zero. Examples of solving technological problems are given: extrusion of cylindrical billets and wire drawing, rolling of a wide strip of rectangular profile. It is shown that the problems of determining the stress-strain state of isotropic rigid-plastic bodies along the known trajectories of movement of material points are statically definable.

An Effectiveness Improvement of the Pultrusion Process for a Production of Thin-Walled Rectangular Profile

For an effectiveness improvement of conventional pultrusion processes, new optimization methodology is developed by using the design of experiments and response surface technique. An application of this methodology with two objective functions describing the minimum electrical energy spent for a curing and maximum pull speed is successfully demonstrated for the pultrusion process producing thin-walled-rectangular profile.