scholarly journals Geometry optimization of a magnetorheological clutch operated by coils

2016 ◽  
Vol 231 (1-2) ◽  
pp. 100-112 ◽  
Author(s):  
Francesco Bucchi ◽  
Paola Forte ◽  
Francesco Frendo
Keyword(s):  
Smart Materials ◽  
Magnetic Circuit ◽  
Geometry Optimization ◽  
Magnetorheological Fluid ◽  
Lumped Parameter Model ◽  
Finite Element Models ◽  
Optimal Geometry ◽  
Shock Absorbers ◽  
Lumped Parameter ◽  
Available Volume

Magnetorheological fluids are smart materials responsive to magnetic field, widely applied in dampers and shock absorbers but also in clutches and brakes. The magnetorheological fluid gap shape is a very important topic in the design of clutches, since it directly influences the transmissible torque and the power loss. In this paper, an approach to magnetorheological fluid clutch design based on optimization is proposed and tested on four different layouts. Starting from a given available volume, two magnetorheological fluid gap shapes, namely single cylinder and multi-disc, and two coils positions, i.e. internal or external, were considered. A lumped parameter model was developed to analytically compute the magnetic flux along the clutch magnetic circuit and to calculate the transmissible torque of the clutch. The optimal geometry of the clutch for maximum transmissible torque, in terms of number and dimensions of the coil sectors, was determined for each shape and coil configuration and the results were validated by finite element models.

scholarly journals Influence of the Preformed Coil Design on the Thermal Behavior of Electric Traction Machines

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 959
Author(s):  
Benedikt Groschup ◽  
Florian Pauli ◽  
Kay Hameyer
Keyword(s):  
Finite Element ◽  
Fill Factor ◽  
Test Bench ◽  
Simulation Models ◽  
Lumped Parameter Model ◽  
Finite Element Models ◽  
Lumped Parameter ◽  
Detailed Simulation ◽  
Electric Traction ◽  
Heat Transition

Preformed coils are used in electrical machines to improve the copper slot fill factor. A higher utilization of the machine can be realized. The improvement is a result of both, low copper losses due to the increased slot fill factor and an improved heat transition out of the slot. In this study, the influence of these two aspects on the operational improvement of the machine is studied. Detailed simulation models allow a separation of the two effects. A preform wound winding in comparison to a round wire winding is studied. Full machine prototypes as well as motorettes of the two designs are built up. Thermal finite element models of the stator slot are developed and parameterized with the help of motorette microsections. The resulting thermal lumped parameter model is enlarged to represent the entire electric machine. Electromagnetic finite element models for loss calculation and the thermal lumped parameter models are parameterized using test bench measurements. The developed models show very good agreement in comparison to the test bench evaluation. The study indicates that both, the improvements in the heat transition path and the advantages of the reduced losses in the slot contribute to the improved operational range in dependency of the studied operational point.

Nonlinear Dynamics of Planetary Gears Using Analytical and Finite Element Models

2007 ◽  
Author(s):  
Robert G. Parker ◽  
Vijaya Kumar Ambarisha
Keyword(s):  
Finite Element ◽  
Period Doubling ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Finite Element Models ◽  
Two Dimensional ◽  
Tooth Contact ◽  
Planetary Gears ◽  
Lumped Parameter ◽  
Mesh Phasing

Vibration induced gear noise and dynamic loads remain key concerns in many transmission applications that use planetary gears. Tooth separations at large vibrations introduce nonlinearity in geared systems. The present work examines the complex, nonlinear dynamic behavior of spur planetary gears using two models: (i) a lumped-parameter model, and (ii) a finite element model. The two-dimensional lumped-parameter model represents the gears as lumped inertias, the gear meshes as nonlinear springs with tooth contact loss and periodically varying stiffness due to changing tooth contact conditions, and the supports as linear springs. The two-dimensional finite element model is developed from a unique finite elementcontact analysis solver specialized for gear dynamics. Mesh stiffness variation excitation, corner contact, and gear tooth contact loss are all intrinsically considered in the finite element analysis. The dynamics of planetary gears show a rich spectrum of nonlinear phenomena. Nonlinear jumps, chaotic motions, and period-doubling bifurcations occur when the mesh frequency or any of its higher harmonics are near a natural frequency of the system. Responses from the dynamic analysis using analytical and finite element models are successfully compared qualitatively and quantitatively. These comparisons validate the effectiveness of the lumped-parameter model to simulate the dynamics of planetary gears. Mesh phasing rules to suppress rotational and translational vibrations in planetary gears are valid even when nonlinearity from tooth contact loss occurs. These mesh phasing conclusions, however, are not valid in the chaotic and period-doubling regions.

scholarly journals A Distributed Lumped Parameter Model of Blood Flow

2020 ◽  
Vol 48 (12) ◽  
pp. 2870-2886
Author(s):  
Mehran Mirramezani ◽  
Shawn C. Shadden
Keyword(s):  
Blood Flow ◽  
Lumped Parameter Model ◽  
Lumped Parameter

scholarly journals Design of External Rotor Ferrite-Assisted Synchronous Reluctance Motor for High Power Density

2021 ◽  
Vol 11 (7) ◽  
pp. 3102
Author(s):  
Md. Zakirul Islam ◽  
Seungdeog Choi ◽  
Malik E. Elbuluk ◽  
Sai Sudheer Reddy Bonthu ◽  
Akm Arafat ◽  
...  
Keyword(s):  
Rare Earth ◽  
Permanent Magnets ◽  
Design Procedure ◽  
Lumped Parameter Model ◽  
High Power Density ◽  
Analytical Design ◽  
Synchronous Reluctance Motor ◽  
Lumped Parameter ◽  
Reluctance Motor ◽  
External Rotor

The rare-earth (RE) permanent magnets (PM) have been increasingly adopted in traction motor application. However, the RE PM is expensive, less abundant, and has cost uncertainties due to limited market suppliers. This paper presents a new design of a RE-free five-phase ferrite permanent magnet-assisted synchronous reluctance motor (Fe-PMaSynRM) with the external rotor architecture with a high saliency ratio. In such architecture, the low magnetic coercivity and demagnetization risk of the ferrite PM is the challenge. This limits the number of flux barriers, saliency ratio, and reluctance torque. A precise analytical design procedure of rotor and stator configuration is presented with differential evolution numerical optimizations by utilizing a lumped parameter model. A 3.7 kW prototype is fabricated to validate the proposed idea.

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