Optimal Geometric Dimensions Research Articles

Reflective multi-layer metasurface based on half-wave plate structure for polarization control in the visible-near-infrared region

The precise control of the polarization of the electromagnetic field in the optical range is studied. A numerical simulation was performed, which corresponds to the optical devices operating in the 650–800 nm range and does not present any obstacles for fabrication. According to this, the three-layer system based on metasurfaces was developed, which operates as a half-wave plate consisting of a metal-dielectric-metal structure and takes very small dimensions, more than 3 times smaller than the observed wavelength. This half-wave plate is reflective and exhibits almost ideal behavior with a spectral width of about 10 nm within 735–745 nm. The losses are negligible, and the amplitude ratio of the directly reflected components in almost the entire studied spectrum exceeds 90%. With a spectrum of about 100 nm within 650–800 nm, it is 99%. Also, the system has an advantage characteristic of metasurfaces: regardless of the angle of the incident wave with the normal, it shows high efficiency, and even when the incident wave is below 45°, the polarization conversion ratio (PCR) remains greater than 80%. The system has optimal geometric dimensions, which works especially well, but even if the dimensions change (due to fabrication defects), its effectiveness does not weaken. The proposed system can become a very promising optical device and be used to control the state of electromagnetic waves in the optical range.

Design and analysis of Si photonic NaCl sensors based on suspended microdisk resonators

In this paper, two optical refractive index sensors, respectively based on a suspended microdisk resonator (SMDR) and a sub-wavelength Bragg grating suspended microdisk resonator (SWG-SMDR) have been designed on a silicon on insulator (SOI) platform, and their optical and sensing performances have been analyzed using the three-dimensional finite-difference time-domain method. It has been shown that the Bragg grating increases the optical confinement factor in the sensing region and, consequently, improves the light–matter interaction and sensitivity. Considering concentrations of 0 to 25% for the NaCl dissolved in the deionized water, the enhanced sensitivity and FOM of the SWG-SMDR sensor with the miniaturized optimal geometrical dimensions are 163.77 nm RIU−1 and 10.81 RIU−1, respectively. This compact optical sensor enhances the sensitivity and FOM by combining effects of the Bragg grating and suspension configuration in improving the light–matter interaction.

Design and empirical evaluation of a magneto-rheological fluid-based seal with rectangular and trapezoidal pole head

The focus of this study is on the design and experimental validation of MRF self-sealing (also known as MRF seal) utilizing permanent magnets. The MRF seal has been built to readily replace traditional seal (lip-seal) for rotation shaft sealing. Following a review of studies on MRF seals, two configurations of MRF seal featuring an axial permanent magnet and two distinct pole head forms, rectangular and trapezoidal, are presented. The two MRF seals are then subjected to a magnetic analysis using the finite element method (ANSYS APDL). The Bingham plastic model of MRF and the assumption of linear velocity profile of MRF in the sealing gap are employed to construct mathematical models of crucial seal characteristics such as maximum static working pressure and frictional torque. The seals are optimized employing the optimization toolbox integrated in the ANSYS APDL to obtain the optimal geometric dimensions of the MRF seals. Finally, prototypes of the two MRF seals are fabricated and testing work is conducted to validate and compare them with the simulated results.

АРМИРОВАНИЕ СТЕН И ПЕРЕКРЫТИЯ ПРИ ВОЗВЕДЕНИИ ЗДАНИЙ С ПОМОЩЬЮ АДДИТИВНЫХ ТЕХНОЛОГИЙ.

In continuation of the work on the establishment of optimal geometric dimensions of structures intended for the construction of buildings using additive technologies, the main structural approaches for the reinforcement of walls and floors are determined. As the main variant of the overlap device, a rotary segmental structure with a half-wave length of 0,6 m was adopted, while the angle of inclination of the connecting element between the upper and lower belt is 270, a similar design solution was adopted for the wall structure. The calculation is carried out by the finite element method. Modeling is performed by shells with absolutely rigid bodies at the interface of the wave and the belts of structures. The results of the reinforcement calculation show that for the construction of walls with a total thickness of 400 mm, reinforcement should be performed only constructively at the point of the overlap support, for the pivoting segments of the overlap with a total thickness of 250 mm, reinforcement is mandatory and does not depend on the length of the span. The diameter of the reinforcement for spans in the range of 3,0-8,4 m of the overlap structure and various payloads is calculated, according to the results of the reinforcement selection, it is concluded that the spans of the rotating segments of the overlap should be performed no more than 7,2 m. The article was prepared as part of the implementation of the state task in the field of science for the implementation of scientific projects implemented by the teams of scientific laboratories of educational institutions of higher education subordinate to the Ministry of Education and Science of the Russian Federation under the project “New materials and technologies for the construction of buildings, structures and their elements using robotic additive systems” (No. FEWN-2023-0004).

Output performance improvement for thermoelectric transistor with the consideration of the Thomson effect and geometry optimization

Despite significant attention paid to thermoelectric generators in the energy conversion field, their limited output performance has restricted their large-scale applications. Therefore, there is a pressing need to conceive a novel thermoelectric device concept that can strengthen their competitiveness. In this context, the concept and principle of thermoelectric (TE) transistor with ultrahigh performance is a demand-driven innovation. Built on the foundation of a PNP structure, TE transistor only relies on the Seebeck voltage to operate normally. This work employs P-type Bi0.5Sb1.5Te3 and N-type Bi2Te2.97Se0.03 as the component materials. By considering the conduction heat, Joule heat, Thomson heat, and temperature-dependent material properties, a one-dimensional heat transfer model was used to obtain the nonlinear temperature profile inside TE transistor. Further, the structure and operation conditions of TE transistor with varying geometric dimensions were determined based on the hole concentration distribution and build-in voltage variation. Finally, the optimal concentrations and geometric dimensions of TE transistor were obtained using a compromise method. The calculation results reveal that TE transistor can achieve an optimal output power of 133.7 mW under a temperature difference of 50 K (Th = 353 K, Tc = 303 K) with the corresponding conversion efficiency of 7.73%. This work provides theoretical guidance for future experimental validation of TE transistor.

Novel busbar design for screen-printed front side Al metallization of high-efficiency solar cell

The need to reduce the silver consumption for future global PV production requires novel approaches for cell metallization and module integration. A screen-printed aluminum cell metallization on the front side could contribute here, but requires a redesign of the solder pads and busbars. A compromise between shading and resistive losses is needed. We investigate the inclusion of Ag solder pads in high-aspect-ratio Al finger grids on the front side of p-type back junction solar cells featuring passivating polysilicon on oxide (POLO) contacts on the rear side. In order to determine the optimal geometric dimensions of the solder pads, we characterize the resistance at the interface between the Ag solder pads and the Al finger grid in dependence on the size of the overlap between the two paste. A contact resistance of 285 mΩ is determined for 200 μm-narrow Al busbars and small solder pads of 750 μm in length. This would require tens of solder pads per busbar for acceptable power losses below 0.5 % coming along with significant shading. Therefore, a new metallization design is developed. We use narrow Ag busbars with a widened intersection to the Al fingers in order to reduce the contact resistance caused by the Ag–Al alloy. Thereby, the shading losses of the solderable busbars and pads are less than 1.5 %.

Experimental and numerical analysis of shape memory sinusoidal lattice structure: Optimization through fusing an artificial neural network to a genetic algorithm

Shape memory polymers are smart materials that can “remember” their original shape and return to it when exposed to certain stimuli, such as heat, light, or a change in pH. This research investigates the compressive nonlinear response of a sinusoidal shape memory unit cell made of PLA. Different architectures with diverse thicknesses are optimized through a finite element analysis, and the values of absorbed energy, dissipated energy, and peak force are extracted. The obtained data is subsequently used to train a judiciously structured artificial neural network. Three algorithms, including Levenberg-Marquardt, Bayesian regularization, and scaled conjugate gradient backpropagation, are utilized for training the neural network. The function obtained is employed to formulate the objective function to be minimized- (or maximized), and the optimal geometric dimensions are extracted. In the experimental part, the sinusoidal cell is made using a 3D printer and PLA material, and a quasi-static test is performed. After each quasi-static test, the structure is exposed to heat, and thanks to its shape memory properties, it returns to its original shape. This cycle is repeated up to four times. Testing results showed that the proposed sinusoidal structure possessed an attractive mechanical behaviour relevant to the specific geometric parameters and loading conditions. It was observed that the amount of absorbed energy and the maximum forces decreased in each cycle compared to the previous cycle. The experimental results demonstrate that the absorbed energy by the sinusoidal cell decreased by 4.7% in the second loading, 12.98% in the third loading, and 33.7% in the fourth loading. The results reveal that the reduction in the peak force of structure is more pronounced compared to the decrease in absorbed energy under cyclic loading–unloading. Based on the obtained results, it can be concluded that the proposed structure can be used as a suitable energy absorber with the ability to recover the original shape and maintain the mechanical properties up to several cycles of loading.

The optimal geometric design of a v-corrugated absorber solar air heater integrated with twisted tape insert

The proper design of a solar air heater depends on the highest thermal performance of the solar collector. In the present paper, proposed a method to find an optimal dimension of V-corrugated absorber solar air heater (VSAH) combined with a twisted tape insert (TTI). The design variables of the VSAH-TTI are length, width, number of channels, and twisted tape ratio. The effect of each design variable is examined and studied under various ranges of Reynolds number (Re). Given the complexity in changing design variables of solar collector having a V-corrugated absorbing plate with twisted tape insert (VSAH -TTI) to find the highest thermal performances, the multi-objective function genetic algorithm is used to find the optimal dimensions of VSAH-TTI based on maximizing the heat gain, thermal and effective efficiency as well as minimizing the pressure drop on solar collector. The range of each design variable of the VSAH-TTI by means of length (1 – 2.5 m), width (0.5 – 1.5 m), number of channels (4 – 14), and twisted tape ratio (1 – 8) are specified in paper based on the most common practical values of the solar collector. The results showed for the case under study that each design variable of VSAH-TTI affect the thermal performance and the optimized geometry by using a genetic algorithm (Ga) can find the optimal geometric dimensions of VSAH-TTI. The optimal dimension by using Ga can increase the heat gain by more than 8% and increase the effective and thermal efficiency of more than 7% for the original geometry. Furthermore, the optimized geometry can reduce more than 29% for the original geometry. These improvements in optimized geometry for VSAH- TTI without introducing any additional items.

Determination of the Optimum Operating Conditions and Geometrical Dimensions of the Plate Fin Heat Sinks Using Teaching-Learning-Based-Optimization Algorithm

Abstract Electronic devices must be effectively cooled for long-term reliability and safe operation. It is essential to determine operating conditions and optimum dimensions of cooling devices in terms of device weight, space, cost, and sound limits. Plate fin heat sinks (PFHSs) are frequently used for cooling electronic devices. Optimum thermal designs of PFHSs are explored in this study using a teaching-learning-based-optimization (TLBO) algorithm where entropy generation (S˙gen) minimization, profit factor (J) maximization, base plate temperature excess (θb) minimization, total mass (mass) minimization, and total volume (volume) minimization are the objective functions of the constrained single-objective optimization problems. For further investigations of the entropy generation minimization method, three different optimization problems are also studied: minimization of thermal resistance (Rth), minimization of pressure drop (ΔP), and minimization of pumping power (W˙pump). Each optimization problem is subjected to a constraint, namely, temperature excess of base plate temperature (θb) should be lower than 10 K. Four optimization variables are considered which are the number of plate fins (N), freestream velocity (Vf), the thickness of the fin (tfin), and height of the fin (Hfin). Optimum configurations belonging to the different optimization problems are compared, and the effect of each optimization variable on the objective functions is discussed in detail. It is found that one can obtain optimum operating conditions and geometrical dimensions of the PFHSs according to the design objective, i.e., minimum mass requirement, space limitation, minimum base plate requirement, etc. As a result, the optimum designs of the studied cases are different which are superior to each other in terms of design targets.

Numerical investigation on thermal performance of thermoelectric-cooler integrated cold plate of thermal control liquid loop in spacecraft

The traditional single-phase fluid loop (SFL) and traditioanl thermal control algorithm can barely control the temperature rapidly. Thermoelectric cooler (TEC) has been proved to be a good thermal controller because of its high reliability, liquid-free characteristics, and fast response. This paper proposes a TEC-based precooling module that resides in front of the cold plate (CP), and consists of a TEC-CP system, manifesting a high compatibility between the novel precooling module and traditional SFL. The TEC-CP system was designed, and a mathematical model of heat and mass transfer was developed to numerically investigate the effects of the geometric parameters, TEC operating conditions, and liquid cooling states of the precooling module upon payload thermal performance. Through analysis, an optimal TEC-based precooling module with optimal geometric dimensions was attained, where the coolant temperature was decreased by 13.04 K, resulting in a 28.98% reduction compared to that without the precooling module. Transient results also demonstrate that the temperature response time can be within 3 min, indicating a fast response system for temperature control. Results outlined in this paper provide structural and data references for future designs of scientific rack-level thermal control loops in space stations.

Numerical study of modified centrifugal cyclone

A cyclone separator is an equipment that separates particles contained in a liquid or gas without filters. Dust particles in flue gases can be separated using centrifugal forces and different particle densities so that the exhaust gases must be cleaned before being discharged into the environment. The selection of optimal geometric dimensions and operation parameters of industrial equipment is always a topical issue. In the work, numerical modeling and research of a modified centrifugal cyclone dust collector are carried out. A modified centrifugal cyclone was developed by one of the article's authors at the Institute of Mechanics and Seismic Resistance of Structures of the Academy of Sciences of the Republic of Uzbekistan, which has a high efficiency of at least 98%. The study was carried out in the Comsol Multiphysics 5.6 engineering software package using the Flow Simulation add-on, designed to simulate hydrodynamic processes. The relevance of the chosen research topic was indicated. The standard k-ɛ model is chosen as a turbulence model, which is often used in engineering problems. The computational experiment was carried out at three flow rates in the centrifugal cyclone. Based on the obtained numerical data, it is shown that the efficiency of the modified cyclone is significantly higher than that of the classical cyclone.

Применение СВЧ измерений для сортировки составных элементов археологических объектов

In this paper the design of a coaxial resonant measuring converter with a shortening capacitance used to determine the electrophysical parameters of the constituent elements of archaeological objects is proposed. Based on the numerical model, the optimal geometric dimensions of the resonant sensor are determined. The analysis of the main characteristics of the measuring transducer is carried out. A number of experimental data were obtained confirming the applicability of the proposed technique.

Geometry Optimization of the Runner Insert for Improving the Appearance Quality of the Injection Molded Auto Part.

Appearance quality is one of the most important indexes for many injection-molded products, like optical parts, automotive parts etc., especially at the area near the injection gate. Different from the work that focused on designing the dimensions of the runner, this work proposed a method which is based on the insert technology to improve the appearance quality of a standard automotive part. An insert was introduced into the runner system which located before the gate. Three different shapes of this insert (circular, rectangular and diamond) were used to study the effect of geometrical factors on the appearance quality in this paper. All inserts were parameterized to describe their location and dimensions. Based on the geometrical design parameters, expected improvement optimization problem about the appearance quality were solved by using sequential approximate optimization method. The appearance qualities of three cases are improved by 13.77%, 21.56%, 14.37% respectively. Results showed that the best geometrical design scheme of the insert is rectangular with the optimal geometrical location and dimensions. The reasons were discussed by investigating the flow and thermal history in detail. Compared with the design case without any insert, the heat was absorbed and the velocity field was changed by the insert before the polymer melts ran into the cavity. It changed the complicated thermo-mechanical history inside the material during the entire processing history, which improved the final appearance quality of this auto part.

A computational design of robotic grasper by intelligence-based topology optimization for microassembly and micromanipulation

In robotic microassembly and micromanipulation, robotic grasper plays a vital role in picking up and releasing the product. However, the design synthesis method for creating a new robotic grasper has not deeply considered yet. Therefore, this article presents an effective computation method for designing a new robotic grasper that can be used for microassembly and micromanipulation. Firstly, a new structural scheme of robotic grasper is made by using the topology procedure. The compliance is the objective with the stress constraint during the topology. Then, a new variant of the grasper is refined where compliant joints are needed to reach the better compliance and the elastic motions of grasping hands. In the second phase, the modeling establishment for predicting the behaviors of the grasper are built via using the intelligent computation, namely GENFIS#1-neuro-fuzzy inference system (ANFIS), GENFIS#2-ANFIS, and GENFIS#3-ANFIS. The numerical data of the grasper are collected via the design of experiment-based finite element method. The results indicated that the GENFIS#3-ANFIS type is the best solver for modeling the hand’s stroke, the resonant frequency, and the strain energy. Meanwhile, the GENFIS#2-ANFIS type was the best procedure for modeling the stress. Subsequently, the optimum geometrical dimensions of the grasper are searched by using the Bonobo optimizer to improve the four mentioned performances of the grasper. In the circumstance #1, the results found that the hand’s displacement is about 0.0922 mm, the resonant frequency is 67.6247 Hz, the elastic energy is 1.4550 mJ, and the stress is 6.7249 MPa. The circumstance #2 determined the resonant frequency of 67.6247 Hz, the hand’s displacement of 0.0883 mm, the elastic energy of 1.9914 mJ, and the stress of 6.7086 MPa. Finally, the circumstance #3 found the elastic energy of 2.0501 mJ, the hand’s displacement of 0.0884 mm, the resonant frequency of 80.0012 Hz, and the stress of 6.7046 MPa. Statistically compared with the other methods, the presented method is the simple and effective procedure for designing 3D printed robotic grasper.

Design and Sensitive Analysis of Incremental Linear Actuator

Abstract:This paper presents a novel single-sided linear actuator design and sensitivity analysis of different geometric parameters on the performances of the actuator. A numerical model based on the finite element method is developed for that purpose. Thus, the electromagnetic behavior of the actuator is analyzed with 2D magneto-static analysis, and the electromagnetic characteristics were presented with the study of the effect of different geometric parameters on the thrust force. Indeed, the magnetic flux distribution and the force profile are presented and discussed. The analysis of different parameters on the actuator's performance allows the selection of the appropriate values of these parameters to obtain optimal performance of the actuator. The analysis shows the air gap and stack length has a powerful influence on the actuator's performance. Furthermore, the increase of supply current has a significant effect, but a high level of Ampere turns to bring the magnetic circuit to the saturation zone. It is important to determine the optimal geometrical dimensions to reduce the mass of the motor. It is critical to choose the optimum power values for the actuator to obtain optimum performance and avoid exceeding operating limits.Background:The linear switched reluctance motor is used in many industrial applications such as the linear motion of machine tools, sliding door applications, and conveyors.Objective:A new design approach for a linear switched reluctance motor is developed in order to determine the geometric parameters of the structure.Methods:Finite element method is used to predict the characteristics of the motor and the analysis its performances.Results:The simulation results obtained by finite element analysis make it possible to study the electromagnetic behavior of the motor and to validate the established geometric model.Conclusion:The study was carried out to choose the optimal parameters in order to obtain optimal performance and avoid exceeding the operating limits of the motor.

Optimizing geometric parameters for the rotor of a traction synchronous reluctance motor assisted by partitioned permanent magnets

This paper considers partitioning parameters and the mutual arrangement of magnets in the rotor of the traction synchronous-jet engine with permanent partitioned magnets. The synthesis of geometrical parameters for the rotor of a synchronous reluctance motor with partitioned permanent magnets was proposed on the basis of solving the problem of conditional optimization. To solve the synthesis problem, a mathematical model has been built to determine the electromagnetic momentum of a synchronous reluctance motor with partitioned permanent magnets. It is based on the calculation of the electromagnetic momentum of the engine employing the results of a finite-element analysis of the magnetic field in the flat-parallel statement of the problem. The model is implemented in the finite-element analysis FEMM environment and makes it possible to determine the electromagnetic momentum of the engine with a variety of partitioning of permanent magnets. As an analysis problem, it is proposed to use a mathematical model of the magnetic field of the engine. The problem of conditional optimization of the rotor of a synchronous reluctance motor was stated according to the geometric criteria of the rotor. Restrictions are set on geometric, strength indicators, as well as on the level of electromagnetic momentum. The chosen optimization method is the Nelder-Mead method. Based on the results of solving the problem of synthesizing parameters for the partitioned rotor of the traction motor of trolleybus wheels, it was established that the volume of permanent magnets was reduced by 2.27 times compared to the base structure; their optimal geometric dimensions were determined (5 mm, 5.2 mm, and 5 mm), as well as the distance between them, 17.8 mm and 15.3 mm, and the engine load angle, which is 121.12 electrical degrees. Based on the results of solving the problem of synthesizing parameters for the partitioned rotor of a trolleybus traction synchronous reluctance motor, its optimal geometric parameters have been determined

Multi-Objective Optimization Design and Dynamic Performance Analysis of an Enhanced Radial Magnetorheological Valve with Both Annular and Radial Flow Paths

This article proposes an analytical methodology for the optimal design of a magnetorheological (MR) valve constrained in a specific volume. The analytical optimization method is to identify geometric dimensions of the MR valve, and to determine whether the performance of the valve has undergone major improvement. Initially, an enhanced radial MR valve structure with effective annular and radial composite flow paths was designed. After describing the schematic configuration and operating principle of the proposed MR valve, a mathematical model of the pressure drop was derived on the basis of the Bingham model of a MR fluid. Sequentially, the multi-objective optimization problem had been formulated for the constructed approximate model exploiting the NSGA-II algorithm to find the global optimum geometrical dimensions of the enhanced radial MR valve. Meanwhile, influences of the geometrical design variables of the MR valve were analytically investigated by mapping finite element analysis numerical responses with response surface techniques. Lastly, the experimental test rig was setup to explore the pressure drop and dynamic response time of the initial and optimal MR valve, as well as the dynamic performance of the enhanced radial MR valve controlled cylinder system under different excitation conditions. The experimental results revealed that under the applied current of 1.6 A, the pressure drop and power consumption of the optimal MR valve improved significantly with values of 4.46 MPa and 16.84 W, respectively, when compared to 4.03 MPa and 27.65 W of their respective initial values. Additionally, the average response time efficiency improved by 14.29%, with its optimal value being 81 ms and initial value as 94.5 ms. Moreover, the damping force of the optimal MR valve-controlled cylinder system was 4.34 kN, which was 12.44% larger than the initial one of 3.86 kN at the applied current of 1.6 A.

Experimental investigation of energy consumption for the process of initial heating of a substrate for the use of electric heat-mechanical system

Purpose. Experimental determination of energy consumption for the process of initial heating of the substrate to the temperature of anaerobic digestion in a biogas reactor using an electrothermal-mechanical system with automatic control to assess the energy efficiency of the process of heating the substrate and the profitability of further processing of the resulting biogas into thermal and electrical energy.
 Methodology. Experimental studies of the dynamics of temperature changes in an heating cable placed in an electrothermal-mechanical system, determining the duration of the process and the energy consumed by the initial heating of the substrate, processing and analysis of the obtained data arrays, summarizing the results obtained.
 Findings. Biogas technologies play an important role in the formation of a modern energy system, the profitability of which directly depends on the energy efficiency of anaerobic digestion intensification. The process of digestion of waste is long, so one of the main methods of intensification of biogas production is the mixing of waste in the process of anaerobic fermentation. There is a need to improve the energy efficiency of anaerobic digestion intensification and the profitability processing of biogas into heat and electricity. Ways to improve energy efficiency mainly consist in reducing the time of heating the substrate in a biogas reactor, reducing the consumption of electrical energy for the process of thermal stabilization of anaerobic digestion, structural combination of energy-efficient systems for mixing and heating raw materials in reactors, and introducing automatic production systems. The implementation of these actions will make it possible to establish the optimal geometric dimensions of an electrothermal-mechanical system with automatic control for mixing and heating the substrate in a biogas reactor and significantly increase the energy efficiency of biogas plants and the subsequent processing of the resulting biogas into thermal and electrical energy.
 Originality. As a result of the experimental study and analysis of the data obtained, it was found that with the same power of the heating sections, the change in the temperature of the electric cable in each blade does not occur in the same way. The authors found that the average value of the temperature of the sections of the electric heating cable of the lower blades is 12.9% higher compared to the upper blades of the electrothermal-mechanical system. In the course of experimental studies, the authors found that when using a heating system made of an electric heating cable mounted in the blades of a two-tier paddle mixer, it consumes J, on the process of initial heating of the substrate from before °С in a biogas reactor with a volume of 40 liters. The duration of the heating itself is 300 minutes. In the course of experimental studies, the authors established the energy efficiency from dividing the electrothermal-mechanical system into heating sections, when each blade is a separate section with its own automatic temperature control of the electric heating cable mounted in the corresponding section, while the consumption of electrical energy is reduced by 27.9%.
 Practical value. The results obtained can be used in the design, construction and modernization of biogas production intensification systems, namely, mixing and heating of the substrate in biogas plants. This will improve the energy efficiency of the biogas formation process and the profitability of its processing into heat and electricity.

Design and Optimization of an In-wheel Unequal Stator Teeth Motor

Recently, many researches have been focusing on finding new machine topologies that maximize the efficiency and minimize the mass of in-wheel motors for electric vehicles. This paper presents the design and the optimization of a new in-wheel motor for electric vehicles. This was achieved by proposing a new topology including unequal stator teeth. The design of the machine was performed with an analytical model that considers the slotting effect and the saturation when calculating the air gap flux density. The main purpose of the optimization process is to determine the optimal machine geometric dimensions. This optimization was performed according to three objective functions while respecting a set of constraints. The first objective function is to maximize the machine’s efficiency, the second is to minimize the mass, and the third is to minimize the torque ripple. In this regard, four multiobjective optimization algorithms were employed: two of them belong to the particle swarm optimization family, and the others are genetic algorithms. An optimized machine design was chosen and analyzed using finite element analysis (FEA). The comparison of FEA and optimization results showed a good agreement between both of them, and proves the validity of the proposed design.

Effect of bottom gating system design on filling rate of chill mould

The effect of the bottom gating system design on filling rate of the chill mould by aluminum alloy is considered. Additional element of the system is proposed, which makes it possible to control the melt rate in the mould channels and to reduce the contamination of castings by oxides. The regularities of the effect of the additional element volume of the gating system on the maximum melt rate in the gate and the metal utilization factor are established. It is indicated that the optimal geometric dimensions of the additional element and the channel connecting it with the rest of the gating system depend on the configuration of the casting, its position in the mould, the location of the melt supply, and on the required law of speed variation in the gate.