This study aimed to provide the analytical design, optimization, and three-dimensional (3D) simulation through finite element method of a Coreless stator axial field flux-switching motor (AFFSM). The motor consists of two indented rotors with a Coreless stator between them consisting of a magnet and winding. First of the motor electrical and magnetic design was performed and its basic parameters were calculated. Then, the optimization of the machine was evaluated implementing the Taguchi algorithm in order to minimize the motor cogging torque. Some of the basic motor dimensions, such as the magnet length and width, the rotor tooth width and height, and the back iron thickness, were selected as optimization variables, and the best combination of these variables was obtained by changing them in a certain range to achieve the desired objective. Then, the accuracy of analytical design and optimization was evaluated through forming a 3D finite element method (FEM) of the motor and investigating its performance. Comparison of the optimized and primary motor revealed that the optimal design had a better performance than the initial. Finally, a prototype of the proposed motor was fabricated and tested, which indicated that the experimental results were largely similar to the analytical results.

Compactness and lightness make high-speed axial-flux machines eligible for distributed generation application with microturbine. In a high-speed generator driven by micro-turbines, the rotor speed is normally above 30, 000 rpm and may even exceed 100, 000 rpm. The frequency for flux variation is more than 1 kHz. Therefore, designing such a highspeed generator is quite different, in mechanical and electromagnetic respects, from designing conventional generators with low speed and low frequency. Important considerations in designing high-speed axial-flux generators (HSAFG) for microturbine are discussed in this paper. Results of the efficiency sensitivity versus air gap of the machine are also presented.

Coreless axial flux permanent magnet (PM) machines (AFPM) have attracted significant interest over the last decades as an ideal candidate for a wide range of applications. This is generally due to their advantages, such as the high torque density, high power density, and the light weight. This paper investigates the performance of a Coreless axial flux-switching generator (AFSMG) with improved torque characteristics. The inherent feature of the axial flux-switching machines is the high cogging torque. Hence the main advantage and the novelty of this research is addressing a suitable key for its torque characteristics challenges. In this regard, a comprehensive study is done on rotor tooth shape. First, the geometry and the shape of the rotor tooth are optimized, and then the skewing technique is applied to minimize the cogging torque and improve the total harmonic distortion. Finally, the cogging torque and the THD are calculated in the primary design and the optimal design. The Taguchi method is utilized to improve the primary model. A comparative analysis of the primary and optimized model is carried out, which indicates the better performance of the optimized design. Furthermore, the 3D finite element method is applied to verify the results of the presented model.

This paper presents a new structure to overcome some of the difficulties in axial-flux permanent magnet surface-mounted generators. In the new structure with a non-ferromagnetic holder, the centrifugal force acting on permanent magnets is counteracted. Hence, an increase in the rotation speed and the output power of the generator is feasible. The new design is inexpensive and easy to construct. Thus, by development of the proposed structure, it is possible to construct high-speed, low-cost axial-flux permanent magnet generators.         

In this paper, the combined axial flux structure of a permanent magnet synchronous motor with a magnetic gearbox is analyzed with the aim of increasing the torque density. The motor has two rotors with tangential magnetized spoke type PMs and Coreless structure. Modulators perform the role of magnetic field modulation for the stator and rotor over the air gaps. The shape of permanent magnets allows higher efficiency and at the same time lower axial length. Soft magnetic poles of the rotor located between the magnets play a decisive role in the magnetic field distribution as well as the torque and magnetic field profile of the machine. In this paper, the shape of the soft magnetic pole is optimized to obtain a higher sine field distribution and higher output torque in addition to a lower cogging torque using the variable airgap.

In this paper, the nonlinear free and forced axisymmetric vibration of a thin circular plate made of functionally graded material (FGM) with rigid core has been studied. This plate is formulated in terms of von-Karman’s dynamic equation. In this study a semi-analytical approach is developed.For harmonic vibrations, by using assumed-time-mode method and Kantorovich time averaging technique, the governing equations are solved. This problem is solved using MATLAB code. FGM properties vary through the thickness of the plate. FGMs are spatial composites in which material properties vary continuously as well as non-homogeneity. The mass of the core respect to the mass of plate is negligible. For verification, a Coreless FGM circular plate has been solved using this code.The results show a good approximation. The results reveal that the vibration amplitude and volume fraction have significant effects on the resultant stresses in large amplitude vibration of the functionally graded plate with rigid core.

The present investigation aims to synthesize RB031, RB032 manganese bronze alloys equivalent to HTB1 and HTB2 alloys  with additions of silicon  and to characterize them with the help of Microstructure and Mechanical properties. The methodology involves  melting of alloy’s in a 300kg Coreless medium frequency induction furnace, casting them in Permanent and Shell moulds with optimum values of Zinc equivalent and retaining their high mechanical properties. The study includes the development and mechanical property measurements of the alloys synthesized. Characterization has been carried out using Optical Microscopy and Scanning Electron Microscopy with EDAX analysis for investiagtion of compositional variations and inquisition of hardness measurement & tensile properties. It is concluded from this work that RB032 alloy cast in Permanent moulds has superior hardness and tensile properties compared to Shell moulds and far exceeds that of NAB (AB2) alloys processed under similar conditions. Further, this investigation includes grain refinement by suitable Heat treatment studies to combat Hot Tearing since the strength is adequate enough with RB032 exhibiting higher hardness than other two alloys.

In this study, the effect of aluminum alloying element on the microstructural changes, mechanical properties and fatigue life of Hadfield steel was investigated. For this purpose, 2 blocks castings were prepared from Hadfield steel (without Al and with 1. 68 wt% Al addition) by using Coreless induction furnace. After the casting, all the blocks were austenitized in 1100° C for 2 hours and immediately quenched in the pure water. In the next step, uniaxial tensile test, bending fatigue test and hardness test by vickers method were conducted on specimens. Microstructure evaluation was conducted by optical metallography and the fractured surfaces were observed by scanning electron microscopy. As a result, it was found that the sample containing 1. 68 wt% Al had more hardness and greater yield strength but tensile strength, flexibility and fatigue life of lesser compared to sample without Al addition. So, scanning electron microscopy images indicated the occurrence of ductile fracture in tensile test for both samples and was increased fatigue crack growth in the fatigue test due to the addition of aluminum to chemical composition of Hadfield steel.

In this study, effect of chromium addition on the fracture toughness of Hadfield steel was investigated by using charpy impact test. For this purpose, 3 casting blocks were prepared from Hadfield steel (without Cr addition, and containing 1. 5% Cr and 3% Cr) by using Coreless induction furnace. After casting, all blocks austenitized in 1100° C for 2 hours and immediately quenched in the pure water. In the next step, uniaxial tensile test, hardness test and charpy impact test were applied on specimens. Evaluation of the microstructures was conducted by optical microscope and the fractured surfaces were observed by scanning electron microscope. The results of charpy impact test and fracture toughness empirical relationships were used for determination of fracture toughness values of specimens. As a result, it was found that sample without Cr had lowest hardness – highest fracture toughness value – highest critical crack length and the sample containing 3% Cr had the highest hardness – lowest fracture toughness value – lowest critical crack length. Also, scanning electron microscope images indicated increasing crack growth in the charpy impact test specimens by addition of Cr to chemical composition of Hadfield manganese steel.

In this research, the plastic deformation and failure mechanism of sandwich structures with aluminum face-sheets and waste rubber particles core under low-velocity impact loading have been investigated. The drop hammer testing machine was used to apply the impact load to the sample at seven different energy levels 34.3, 68.6, 102.9, 137.2, 154.3, 171.5, and 205.8 J. To achieve the mentioned energy levels, the weight of the hammer was considered constant and equal to 3.5 kg and the standoff distance of the hammer was changed from 1 to 6.5 m. 10 test samples were considered in two types of layering with and without the core of rubber particles. In this series of experiments, the thickness of aluminum face-sheets was constant at 1 mm and two different thicknesses of 16 and 32 mm were considered for the core. Experimental results showed that, the sandwich panel with 16 mm had a 37 and 18 % smaller deformed area for fall heights of 2 and 3 meters, respectively, due to the less porous space between two aluminum face-sheets. Also, compared to the Coreless sandwich structure, the use of a low-mass waste rubber particle cores at low energy levels increased the front sheet perforation diameter by 19 %.