Vernier permanent-magnet (VPM) machines have been obtaining a lot of attention over the past few years due to several advantages, such as their high torque density and simple mechanical structures. ...Moreover, it is found that the torque ripple of VPM machines is ultralow, even without specific design measures such as a short pitch, skewing slots/poles, magnet shaping technology, etc. This paper presents theoretical analysis and comprehensive simulations on the torque ripple of VPM machines. First, a general instantaneous torque equation of VPM machines is proposed to analyze torque features and the effect of parameters on the torque performance of VPM machines. Subsequently, based on the general torque equation and a finite-element algorithm, it is verified that torque smoothness is the inherent characteristic of VPM machines, and the torque ripple of VPM machines can be below 0.2%. Furthermore, it is demonstrated that the torque density of a VPM machine is 40% larger than that of a regular permanent-magnet machine. All these advantages demonstrate that VPM machines can obtain much better steady and dynamic drive performance. Finally, all the theoretical analyses are verified by experiments on a VPM prototype.
•Dental implant anchorage was investigated by experiments, analytical and FE models.•Diameter increased normalized insertion torque and contact for tapered implant.•However, diameter did not affect ...these measures for parallel-walled implants.•Tapered design distributed PU foam stress further away from the thread.•This study demonstrated PU foam compression during insertion for tapered implants.
Anchorage, evaluated by the maximum insertion torque (IT), refers to mechanical engagement between dental implant and host bone at the time of insertion without external loads. Sufficient anchorage has been highly recommended in the clinic. In several studies, the effects of implant diameter and taper body design under external loading have been evaluated after insertion; however, there are few studies, in which their effects on stress distribution during insertion have been investigated to understand establishment of anchorage. Therefore, the objective of this study was to investigate the effects of dental implant diameter and tapered body design on anchorage combining experiments, analytical modeling, and finite element analysis (FEA). Two implant designs (parallel-walled and tapered) with two implant diameters were inserted into rigid polyurethane (PU) foam with corresponding straight drill protocols. The IT was fit to the analytical model (R2 = 0.88–1.0). The insertion process was modeled using explicit FEA. For parallel-walled implants, normalized IT and final FEA contact ratio were not related to the implant diameter while the implant diameter affected normalized IT (R2 = 0.90, p < 0.05, β1 = 0.20 and β2 = 0.93, standardized regression coefficients for implant diameter and taper body design) and final FEA contact ratio of tapered implants. The taper design distributed the PU foam stress further away from the thread compared to parallel-walled implants, which demonstrated compression in PU foam established by the tapered body during insertion.
Abstract
Four types of cooling plates with serpent channel structures are established to study the cooling effect of rectangular lithium-ion power battery under different cooling plates. Then, the ...number of serpent bends is analyzed, whether the fillet and pipe wall thickness is set on the cooling performance of the liquid cooling plate. According to the analysis results, a new liquid flow structure form of liquid cooling plate is designed. Numerical simulation results show that the newly designed cooling plate is integrated with the front flow of water and the internal liquid side flow, achieving a cooling effect with the maximum temperature is 309.55K and a pressure drop of 6032.1pa, which has the most effective cooling performance. Under the requirement of controlling reasonable temperature and low-pressure drop, a liquid cooling plate with better performance can be designed by innovatively setting the direction of the water inlet and outlet and the water channel’s internal flow. The above results will provide some ideas for the design of a lithium-ion battery liquid cooling plate.
While plant fibers find extensive use across numerous applications, their transverse behavior and mechanical properties lack direct and fiber-scale characterization, posing a significant knowledge ...gap. This paper investigates, for the first time, the transverse behavior of flax, hemp and nettle fibers through Single Fiber Transverse Compression Tests (SFTCTs). Finite element analysis is used to study the influence of time-dependent and irreversible inelastic behavior on the fiber’s response and identify configurations fit for the identification of apparent elastic properties. SFTCTs are performed experimentally with a repeated progressive loading protocol using a custom micro-mechatronic setup. An apparent fiber transverse elastic modulus of 1 to 3 GPa is identified by inverse method for all tested fibers, demonstrating high fiber anisotropy. Important inelastic features are also observed on fiber behavior. Their origin is discussed with both material behavior and structural mechanisms such as lumen collapse, identified as the main potential causes.
In order to analyze spoke-type interior permanent magnet synchronous motors (IPMSMs) accurately, it is necessary to apply 3-D finite element analysis (3-D FEA) that takes into account axial leakage ...flux. However, 3-D FEA is disadvantageous due to the significant inputs of time and effort required. Therefore, it is necessary to use 2-D finite element analysis (2-D FEA) to produce reliable analysis. Precise analysis of IPMSMs using 2-D FEA should consider the leakage magnetic flux generated at the axial end of the rotor core. The magnetic loss caused by leakage flux along the axial direction can be considered in 2-D-FEA by estimating the axial leakage flux path of the rotor due to the potential difference between poles and poles and correcting the permeability of the permanent magnets (PMs). The proposed 2-D FEA was applied to analyze a spoke-type IPMSM with overhanging and cross-laminated rotor structures. Finally, the reliability of the proposed analysis method was verified by comparing the results of the proposed model with 3-D FEA results and experimental results.
This paper is a contribution to answering the following question: Is it possible to design a permanent-magnet machine with the performance expected from rare-earth magnets, but at a lower cost? ...Performance being understood as torque, size, efficiency, demagnetization and temperature rise together. The question is addressed with a systematic exploration of different interior permanent-magnet machine topologies mixing rare-earth and ferrite permanent magnets. The study starts from a production baseline, the Prius 2010 traction motor, with interior magnets placed in a single V pattern. It investigates various rotor designs, most specifically, single V and double V patterns as well as spoke configurations. The stator cross-section design and winding selection are fixed, providing a solid comparison basis from the point of view of machine cooling. For each rotor design, torque potential and machine material cost are assessed, the latter expressed as torque per dollar. A promising configuration was found, based on a spoke pattern, for which further modeling was performed to assess efficiency as well as mechanical strength and resistance to short circuits and to demagnetization. It reduces the rare earth magnet volume by over 60%.
Flax fibres offer performance capabilities comparable to glass fibres, thereby enhancing their potential in the biobased composites industry. However, these fibres have morphological defects ...affecting their mechanical features. In the present work, flax elementary fibres geometries with defects assessed by synchrotron X-ray microtomography were meshed to simulate a tensile test using finite element analysis. For the first time, the distribution of stresses in the vicinity of defects is revealed. The geometrical irregularities at the surface of the fibre and the delamination of cellulose layers within fibre cell wall turned out to concentrate stress up to 7.5 times compared to defect-free regions. These results demonstrate why flax fibres cannot reach their full potential in comparison to what could be expected from a structure mainly constituted from crystalline cellulose microfibrils, and why fracture in a composite is likely to initiate in those defect zones.
Bio-inspired engineering design has drawn considerable attention in the recent years for its great structural and mechanical features. This study aimed to explore the energy absorption ...characteristics of a novel bionic-bamboo tube (BBT) structure subjected to axial crushing. The tubes with six different cross-sectional configurations were devised with inspiration of bamboo microstructure. The effects of rib shape and rib number were analyzed by using the finite element code LS-DYNA. The numerical results indicated that the BBT structures with the rib shape of “X” and the rib number of six exhibited the best crashworthiness. To further improve the energy absorption capabilities of these BBT structures, the multiobjective optimization was employed with respect to design variables of configurational structure, such as the rib angle of the “X” shaped cross-section, center distance and rib thickness. The response surface method (RSM) and multiobjective particle swarm optimization (MOPSO) algorithm were adopted to maximize specific energy absorption (SEA) while minimizing peak crushing force (PCF). The optimization results demonstrated that compared to the baseline design, the SEA value of the optimized BBT structure was further increased by 6.84% without sacrificing in peak crushing force.
•Six kinds of bionic-bamboo thin-walled structures (BBTS) were proposed and their energy absorptions were compared.•BBTS with rib shape of “X” and rib number of six showed the best energy absorption capability.•Rib number, rib thickness, angle of rib and center distance had considerable effects on the energy absorption.•Crashworthiness characteristics of optimized BBTS were superior than that of initial design.
In-wheel motors bring a fundamental change in electric vehicle technology by removing conventional mechanical components and freeing up space inside the vehicle body. This approach ultimately helps ...to realize all-wheel independent control for improved vehicle dynamics and increased vehicle design freedom. However, when space allowed for an in-wheel motor is taken into consideration, high torque density, high efficiency, and wide-speed-range capability are typically required. This paper specifically investigates a 20-pole-24-slot surface permanent magnet synchronous motor with consequent pole rotor for in-wheel direct drive since this topology is well suited for high-pole motors and thus high-torque direct-drive applications. Extensive finite-element analysis is carried out to characterize the proposed motor, and the practical feasibility of the proposed motor is discussed. Finally, the validity of the analysis was experimentally verified.
PDF
