Real-time 3D thermal modeling of a magnetically levitated planar actuator

A transient thermal model used to monitor the temperature distribution in real-time in a long-stroke moving-magnet planar actuator is presented. The temperature distribution in the stator coils of the planar actuator depends on the trajectory of the levitated magnet plate as the set of active coils changes with the position of the translator. Using the presented real-time model, the transient thermal behavior can be investigated. Using this thermal model, the commutation algorithm of the planar actuator is adjusted to actively limit the temperature of the coils, and better spread the temperature over the stator coils.     

The deformation of the moving magnet plate of a commutated magnetically levitated planar actuator

This paper presents a method to calculate the deformation of the magnet plate of a commutated magnetically levitated planar actuator using a linked electromagnetic–mechanical model. The force and torque distribution on the moving magnet array is obtained from an electromagnetic model based on the surface charge method and the Lorentz force and torque integral. The mechanical model is a state-space model derived from FEM. This mechanical model uses the force and torque distribution to determine the deformation of the magnet plate during movement due to the commutated coil set.     

A micro-Raman study of phase transformations of zirconia crystals upon introduction of a vickers indentor

A micro-Raman study of zirconia crystals and ceramics performed with the use of argon, He - Ne, and semiconductor lasers is described. The results of the study are shown to depend on the wavelength of the radiation source used. It is shown that argon radiation determines only the monoclinic phase formed upon indentation of low-strength crystals of partially stabilized zirconia, which is not observed in the case of tests of high-strength crystals. The indentation behavior of crystals of partially stabilized zirconia is shown to depend on the tetragonal-monoclinic phase transformation and the rotation of typical ferroelastic domains. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 6, pp. 4–9, June, 2000.     

Strength and crack resistance of zirconium dioxide crystals containing yttrium and terbium oxides

Conclusions We studied the mechanical behavior of the partially stabilized (with yttrium oxide) zirconium dioxide crystals in which a small quantity of terbium oxide was introduced as an additive. The obtained data indicate the suitability of this material for practical applications. The effect of heat treatment on the physical and mechanical properties of such materials was revealed. It was established that on cooling up to –150°C, their strength and thermal shock resistance are improved.The lack of correspondence between the values of the crack resistance determined according to the methods of bend testing and indentation was established. The existence of a significant barrier to fracture was observed. The two possible types of surfaces of the crystals under consideration were revealed and the relationship between the structure of these surfaces (and, also, the near-surface layers adjoining them) and the resistance to fracture was established.Translated from Ogneupory, No. 6, pp. 2–8, June, 1993.     

Electromagnetic and Thermal Design of a Linear Actuator Using Output Polynomial Space Mapping

This paper describes the optimization methodology used in the design of a slotted tubular permanent-magnet actuator for industrial applications. A time-effective optimization procedure is obtained by considering simple analytical design equations in coherence with 2-D finite-element analysis as means to establish the various design variables. The optimization is performed in a multiphysics environment because both electromagnetic and thermal models are created and used in the optimization routine. The original optimization problem is replaced by a surrogate, which is updated or improved iteratively by means of a space-mapping-based technique. Its application for solving coupled magnetic-thermal design problems for electric machines is a rather unexplored topic.     

Structure and conductivity of yttria and scandia‐doped zirconia crystals grown by skull melting

In this paper a detailed study of the (ZrO₂)_1‐x(Y₂O₃)_x (x=0.025–0.15), (ZrO₂)_1‐x(Sc₂O₃)_x (x = 0.06 – 0.11) and (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y (x=0.07 – 0.11; y=0.01 – 0.04) solid solution crystals grown by skull melting technique is presented. The structure, phase composition, and ion conductivity of the obtained crystals were investigated by X‐ray diffraction, transmission electron microscopy, Raman scattering spectroscopy, and impedance spectroscopy. Maximum conductivity as (ZrO₂)_1‐x(Y₂O₃)_x and (ZrO₂)_1‐x(Sc₂O₃)_x solid solution crystals is observed for the compositions containing 10 mol% stabilizing oxide, and the conductivity of 10ScSZ is ~3 times higher than for 10YSZ. Experiments on crystal growth (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y solid solutions showed that uniform, transparent crystals 7Sc3YSZ, 7Sc4YSZ, 8Sc2YSZ, 8Sc3YSZ, 9Sc2YSZ, 9Sc3YSZ, 10Sc1YSZ, and 10Sc2YSZ are single phase crystal containing t″ phase. It is established that a necessary condition of melt growth of (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y single‐phase crystals is the total concentration of the stabilizing oxides from 10 to 12 mol%. The addition of Y₂O₃ affects the (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y solid solution conductivity different ways and depends on the Sc₂O₃ content in the starting composition. The effects of structure, phase composition, concentration, and type of stabilizing oxides on the electrical characteristics of obtained crystals are discussed.     

Change in the mechanism of conductivity in ZrO<Subscript>2</Subscript>-based crystals depending on the content of stabilizing Y<Subscript>2</Subscript>O<Subscript>3</Subscript> additive

The interrelationship between the structure, phase composition, and transport characteristics of solid electrolytes based on ZrO₂ has been studied as dependent on the content of stabilizing Y₂O₃ additive. It is established that twin boundaries do not lead to the appearance of additional mechanism of ionic conductivity acceleration in ZrO₂–Y₂O₃ crystals. The maximum conductivity has been observed in ZrO₂–(8–10) mol % Y₂O₃ crystals containing a t” phase, in which oxygen atoms are displaced from high-symmetry positions characteristic of the cubic phase.     

Application of Schwarz-Christoffel Mapping to Permanent-Magnet Linear Motor Analysis

Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear synchronous motors. These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this paper, an elegant semianalytical approach is presented to acquire the force profile. First, the magnetic field distribution in the air gap is determined by means of Schwarz-Christoffel (SC) mapping. The SC mapping allows a slotted structure of the machine to be mapped to a geometrically simpler domain for which analytic solutions are available. Subsequently, the field solution in the slotted structure can be determined by applying the mapping function to the field distribution in the simplified domain. From the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The results are compared with those from the commonly used equivalent magnetic circuit modeling and 2-D FEM software to demonstrate the accuracy which can be reached by application of the SC method.