scholarly journals Lifetime Analysis of Motorized Spindle Bearings Based on Dynamic Model

2021 ◽  
Author(s):  
Jun Ying ◽  
Zhaojun Yang ◽  
Chuanhai Chen ◽  
Guoxiang Yao ◽  
Wei Hu ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Estimation Method ◽  
Design Stage ◽  
Lifetime Estimation ◽  
Element Analysis ◽  
Actual Structure ◽  
Axial Forces ◽  
Stiffness Model ◽  
Lifetime Analysis ◽  
Motorized Spindles

Abstract The traditional probabilistic-based lifetime evaluation methods for motorized spindles neglect the effects of load dynamic and structure difference. Hence, a dynamic-model-based lifetime estimation method combining these effects is proposed to improve the estimating results for motorized spindles, especially in the design stage. Considering the bearings lifetime has dramatically influenced the reliability of motorized spindles, this paper establishes a shaft-bearing-toolholder based on a dynamic model to estimate the bearing group lifetime. The proposed dynamic model is closer to the actual structure in spindles, indicating the stiffness of bearings and contact surface conditional on the inputting radial-and-axial forces is nonlinear. The stiffness model is verified by finite element analysis and experiment. The load applied to bearings is accurately calculated through the dynamic model. Then, the load is introduced to a well-known bearing lifetime model, thereby calculating the lifetime of each bearing and its group. The bearing lifetime results under different conditions of preload, clamping force, and cutting force are discussed.

Testing of a Folded Plate Space Structure

1987 ◽  
Vol 2 (2) ◽  
pp. 115-121
Author(s):  
D. Ho ◽  
P. K. K. Lee ◽  
H. W. Chung ◽  
W. C. Keung
Keyword(s):  
Finite Element ◽  
Space Structure ◽  
Sufficient Accuracy ◽  
Design Stage ◽  
Stage Model ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Actual Structure ◽  
The Finite Element Analysis ◽  
Before And After

A reinforced concrete folded plate space structure of span 28 m and clear height 9·4 m was constructed as a games hall. The structure was analysed using the finite element method. At the design stage, model tests were carried out to check the accuracy of the method of analysis. To assess the behaviour of the actual structure subject to its self-weight, strains and deflections were monitored during construction both before and after removal of formwork. The tests confirmed that results given by the finite element analysis are of sufficient accuracy for the purpose of design, irrespective of the assumptions involved.

scholarly journals Design and Analysis of a Novel Axial-Radial Flux Permanent Magnet Machine with Halbach-Array Permanent Magnets

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3639
Author(s):  
Rundong Huang ◽  
Chunhua Liu ◽  
Zaixin Song ◽  
Hang Zhao
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Torque Ripple ◽  
Axial Flux ◽  
Element Analysis ◽  
Torque Density ◽  
Axial Forces ◽  
Halbach Array ◽  
Radial Flux ◽  
High Torque

Electric machines with high torque density are needed in many applications, such as electric vehicles, electric robotics, electric ships, electric aircraft, etc. and they can avoid planetary gears thus reducing manufacturing costs. This paper presents a novel axial-radial flux permanent magnet (ARFPM) machine with high torque density. The proposed ARFPM machine integrates both axial-flux and radial-flux machine topologies in a compact space, which effectively improves the copper utilization of the machine. First, the radial rotor can balance the large axial forces on axial rotors and prevent them from deforming due to the forces. On the other hand, the machine adopts Halbach-array permanent magnets (PMs) on the rotors to suppress air-gap flux density harmonics. Also, the Halbach-array PMs can reduce the total attracted force on axial rotors. The operational principle of the ARFPM machine was investigated and analyzed. Then, 3D finite-element analysis (FEA) was conducted to show the merits of the ARFPM machine. Demonstration results with different parameters are compared to obtain an optimal structure. These indicated that the proposed ARFPM machine with Halbach-array PMs can achieve a more sinusoidal back electromotive force (EMF). In addition, a comparative analysis was conducted for the proposed ARFPM machine. The machine was compared with a conventional axial-flux permanent magnet (AFPM) machine and a radial-flux permanent magnet (RFPM) machine based on the same dimensions. This showed that the proposed ARFPM machine had the highest torque density and relatively small torque ripple.

Concurrent Engineering Design of Sheet Stamping by Using an Inverse FE Approach

1997 ◽  
Author(s):  
Shiyong Yang ◽  
Kikuo Nezu
Keyword(s):  
Finite Element ◽  
Concurrent Engineering ◽  
Process Simulation ◽  
Three Dimensional ◽  
Sheet Forming ◽  
Design Stage ◽  
Forming Process ◽  
Element Analysis ◽  
Preliminary Design Stage ◽  
Product And Process

Abstract An inverse finite element (FE) algorithm is proposed for sheet forming process simulation. With the inverse finite element analysis (FEA) program developed, a new method for concurrent engineering (CE) design for sheet metal forming product and process is proposed. After the product geometry is defined by using parametric patches, the input models for process simulation can be created without the necessity to define the initial blank and the geometry of tools, thus simplifying the design process and facilitating the designer to look into the formability and quality of the product being designed at preliminary design stage. With resort to a commercially available software, P3/PATRAN, arbitrarily three-dimensional product can be designed for manufacturability for sheet forming process by following the procedures given.

Mechanical Power Losses of Ball Bearings: Model and Experimental Validation

2021 ◽  
pp. 1-29
Author(s):  
Ahmet Dindar ◽  
Amit Chimanpure ◽  
Ahmet Kahraman
Keyword(s):  
Dynamic Model ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Mechanical Power ◽  
Ball Bearings ◽  
Power Losses ◽  
Euler Parameters ◽  
Surface Shear ◽  
Axial Forces ◽  
Set Up

Abstract A tribo-dynamic model of ball bearings is proposed to predict their load-dependent (mechanical) power losses. The model combines (i) a transient, point contact mixed elastohydrodynamic lubrication (EHL) formulation to simulate the mechanics of the load carrying lubricated ball-race interfaces, and (ii) a singularity-free dynamics model, and establishes the two-way coupling between them that dictates power losses. The dynamic model employs a vectoral formulation with Euler parameters. The EHL model is capable of capturing two-dimensional contact kinematics, velocity variations across the contact as well as asperity interactions of rough contact surfaces. Resultant contact surface shear distributions are processed to predict mechanical power losses of example ball bearings operating under combined radial and axial forces. An experimental set-up is introduced for measurement of the power losses of rolling-element bearings. Sets of measurements taken by using the same example ball bearings are compared to those predicted by the model to assess its accuracy in predicting mechanical power loss of a ball bearing within wide ranges of axial and radial forces.

Development of 1500-r/min 75-Inch Ultra-Long Last Stage Blades for Nuclear Steam Turbine

2017 ◽  
Author(s):  
Deqi Yu ◽  
Jiandao Yang ◽  
Wei Lu ◽  
Daiwei Zhou ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Vibration Monitoring ◽  
Steam Turbines ◽  
Element Analysis ◽  
Rotating Blade ◽  
Lifetime Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Last Stage

The 1500-r/min 1905mm (75inch) ultra-long last three stage blades for half-speed large-scale nuclear steam turbines of 3rd generation nuclear power plants have been developed with the application of new design features and Computer-Aided-Engineering (CAE) technologies. The last stage rotating blade was designed with an integral shroud, snubber and fir-tree root. During operation, the adjacent blades are continuously coupled by the centrifugal force. It is designed that the adjacent shrouds and snubbers of each blade can provide additional structural damping to minimize the dynamic stress of the blade. In order to meet the blade development requirements, the quasi-3D aerodynamic method was used to obtain the preliminary flow path design for the last three stages in LP (Low-pressure) casing and the airfoil of last stage rotating blade was optimized as well to minimize its centrifugal stress. The latest CAE technologies and approaches of Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA) and Fatigue Lifetime Analysis (FLA) were applied to analyze and optimize the aerodynamic performance and reliability behavior of the blade structure. The blade was well tuned to avoid any possible excitation and resonant vibration. The blades and test rotor have been manufactured and the rotating vibration test with the vibration monitoring had been carried out in the verification tests.

Comparison of Numerical Methods for Determining Torsion Stiffness of Automotive Chassis

2011 ◽  
Author(s):  
Steven Tebby ◽  
Ebrahim Esmailzadeh ◽  
Ahmad Barari
Keyword(s):  
Finite Element Analysis ◽  
Analytical Approach ◽  
Torsional Stiffness ◽  
Design Stage ◽  
Element Analysis ◽  
Detailed Design ◽  
Vertical Displacements ◽  
Comparison Of The Results ◽  
Torsion Stiffness

The torsion stiffness of an automotive chassis can be determined using an analytical approach based purely on geometry, using an experimental method, or alternatively by employing a Finite Element Analysis (FEA) process. These three methods are suitable at different design stages and combined together could prove to be practical methods of determining the torsion stiffness of a chassis. This paper describes and compares two distinct FEA processes to determine the torsion stiffness of an automotive chassis during the detailed design stage. The first process iteratively applies forces to the model and records displacements, while the second process gradually applies vertical displacements in place of force to determine the torsional stiffness threshold. Each method is explained and supported with a case study to provide a basis of comparison of the results.

Development of On-Line Monitoring System and Aging Characteristics Research of Switchgear

2013 ◽  
Vol 330 ◽  
pp. 364-367
Author(s):  
Shu Xin Liu ◽  
Yun Dong Cao ◽  
Chun Guang Hou ◽  
Yang Liu ◽  
Xiao Ming Liu
Keyword(s):  
Epoxy Resin ◽  
Monitoring System ◽  
Estimation Method ◽  
Current Transformer ◽  
Insulation Material ◽  
Electrical Characteristics ◽  
Infrared Transmission ◽  
Lifetime Estimation ◽  
Monitoring Method ◽  
On Line

For improving reliable operation of switchgear in power system, an approach for on-line monitoring the insulation characteristic and bus-bar temperature rising of the switchgear is proposed in this paper. Through comparing several existing temperature measurement methods for monitoring temperature rising elevation at bus-bas, a new design of temperature monitoring method is proposed. It adopts quick-magnetic saturated current transformer, temperature sensor and infrared transmission to solve the problem of high voltage isolation. The epoxy resin insulation material which is commonly used in switchgear its aging mechanism data is not complete, seriously restrict on-line monitoring for switchgear, so thousands hours of aging experiment is done on switchgear, systematic study various electrical characteristics variation law on the gradual aging process of epoxy resin insulation materials. Therefore, study on the aging characteristics of switchgearinsulation and its lifetime estimation method is the key technology to understand agingmechanism better, search for new fault diagnostic method and the way to extend theuseful lifetime of switchgear. At last, the system runs in real system and the result shows the on-line monitoring system is stable and reliable which can be provide reference for on-line monitoring system design of switchgear.

scholarly journals Analytical Iron Loss Evaluation in the Stator Yoke of Slotless Surface-Mounted PM Machines

2021 ◽  
Author(s):  
Matteo Leandro ◽  
Nada Elloumi ◽  
Alberto Tessarolo ◽  
Jonas Kristiansen Nøland
Keyword(s):  
Core Loss ◽  
Lookup Table ◽  
Iron Loss ◽  
Estimation Methods ◽  
Design Stage ◽  
Loss Assessment ◽  
Stator Core ◽  
Element Analysis ◽  
Field Solution ◽  
Loss Models

<div>One of the attractive benefits of slotless machines is low losses at high speeds, which could be emphasized by a careful stator core loss assessment, potentially available already at the pre-design stage. Unfortunately, mainstream iron loss estimation methods are typically implemented in the finite element analysis (FEA) environment with a constant-coefficients dummy model, leading to weak extrapolations with huge errors. In this paper, an analytical method for iron loss prediction in the stator core of slotless PM machines is derived. It is based on the extension of the 2-D field solution over the entire machine geometry. Then, the analytical solution is combined with variable- or constant-coefficient loss models (i.e., VARCO or CCM), which can be efficiently computed by vectorized post-processing. VARCO loss models are shown to be preferred at a general level.Moreover, the paper proposes a lookup-table-based (LUT) solution as an alternative approach. The main contribution lies in the numerical link between the analytical field solution and the iron loss estimate, with the aid of a code implementation of the proposed methodology. First, the models are compared against a sufficiently dense dataset available from laminations manufacturer for validation purposes. Then, all the methods are compared for the slotless machine case. Finally, the models are applied to a real case study and validated experimentally.</div>

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