Automated Material Parameter Calibration for an Electric Motor Stator

2021 ◽  
Vol 263 (3) ◽  
pp. 3454-3458
Author(s):  
Hasan Pasha ◽  
Gil Jun Lee ◽  
Henry Zhang ◽  
Steve Hale ◽  
Santosh Kottalgi
Keyword(s):  
Material Properties ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Design Stage ◽  
Switched Reluctance ◽  
Material Constants ◽  
Reluctance Motor ◽  
Vibration Performance ◽  
The Given ◽  
Material Calibration

For accurate prediction of E-motor noise and vibration performance at the design stage, it is important to model the E-Motor stator structural behavior with high fidelity. Orthotropic material properties have been widely used in practice to simulate laminated steel in the stator. In these models, material constants are calibrated to match natural frequencies of critical modes such as oval/triangle/square modes. Typically, identifying accurate material properties is a manual, time-consuming process, involving lots of trial and error. This study presents an automated workflow to calibrate the material properties for the stator with Ansys Mechanical and optiSLang. The developed workflow can track natural frequencies and corresponding mode shapes of critical modes, and adjust material constants automatically to find best material parameters for the given frequencies. It can rotate the mode shapes and find the orientation that gives best match to the measurements based on modal assurance criteria (MAC). This workflow has shown a good correlation between simulation and test in terms of natural frequencies and corresponding mode shapes for the stator of a switched reluctance motor (SRM). Such an automated workflow enables the fast, efficient material calibration process, therefore accurate electric powertrain NVH simulations.

scholarly journals The Effect of Inner Reinforcing Cores on Natural Frequencies of the Lathe Tool Body

2013 ◽  
Vol 21 (Special-Issue) ◽  
pp. 186-192 ◽  
Author(s):  
Ladislav Rolník ◽  
Milan Naď
Keyword(s):  
Material Properties ◽  
Machine Tools ◽  
Structural Modification ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Geometrical Parameters ◽  
Structural Modifications ◽  
Modal Properties ◽  
Machine Productivity ◽  
Lathe Tool

Abstract The contribution is mainly focused on research and development of structural modification of machine tools, lathes in particular. The main aim of the modification is to change the modal properties (mode shapes, natural frequencies) of the lathe tool. The main objective of the contribution will be to formulate, mathematical analyse and evaluate the proposed methods and procedures for structural modifications of the tool, represented by beam body. A modification of modal properties by insertion of beam cores into beam body is studied in this paper. In this paper, the effect of material properties and geometrical parameters of reinforcing cores on natural frequencies of beam body is presented. The implementation will bring benefit on machine productivity, decreasing the machine tool wear and in many cases it will lead to better conditions in the cutting process.

Maximizing the Fundamental Natural Frequency of Triangular Composite Plates

1996 ◽  
Vol 118 (2) ◽  
pp. 141-146 ◽  
Author(s):  
S. Abrate
Keyword(s):  
Natural Frequency ◽  
Material Properties ◽  
Composite Structures ◽  
Natural Frequencies ◽  
Ritz Method ◽  
Laminated Composite ◽  
Composite Plates ◽  
Mode Shapes ◽  
Fundamental Natural Frequency ◽  
Wide Range

While many advances were made in the analysis of composite structures, it is generally recognized that the design of composite structures must be studied further in order to take full advantage of the mechanical properties of these materials. This study is concerned with maximizing the fundamental natural frequency of triangular, symmetrically laminated composite plates. The natural frequencies and mode shapes of composite plates of general triangular planform are determined using the Rayleigh-Ritz method. The plate constitutive equations are written in terms of stiffness invariants and nondimensional lamination parameters. Point supports are introduced in the formulation using the method of Lagrange multipliers. This formulation allows studying the free vibration of a wide range of triangular composite plates with any support condition along the edges and point supports. The boundary conditions are enforced at a number of points along the boundary. The effects of geometry, material properties and lamination on the natural frequencies of the plate are investigated. With this stiffness invariant formulation, the effects of lamination are described by a finite number of parameters regardless of the number of plies in the laminate. We then determine the lay-up that will maximize the fundamental natural frequency of the plate. It is shown that the optimum design is relatively insensitive to the material properties for the commonly used material systems. Results are presented for several cases.

Analysis Performance of SRM Based on the Novel Dependent Torque Control Method

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8203
Author(s):  
Piotr Bogusz ◽  
Mariusz Korkosz ◽  
Jan Prokop ◽  
Mateusz Daraż
Keyword(s):  
Motor Control ◽  
Natural Frequencies ◽  
Control Method ◽  
Torque Control ◽  
The Novel ◽  
Control Methods ◽  
Vibration Acceleration ◽  
Switched Reluctance ◽  
Reluctance Motor ◽  
Source Current

This paper presents a description and the results of simulations and laboratory tests of proposed methods for dependent torque control in a Switched Reluctance Motor (SRM). The proposed methods are based on Dependent Torque Motor Control (Rising Slope), DTMC(RC), and Dependent Torque Motor Control (Falling Slope), DTMC(FC). The results of these studies were compared with those on the Classical Torque Motor Control (CTMC) method. Studies were conducted for each of the analyzed control methods by determining the efficiency of the drive and the RMS of the source current and analyzing the vibrations generated for each of the control methods. The harmonics of the phase currents, which caused an increase in the level of vibrations generated, were determined. The usefulness of the proposed methods for controlling SRMs was assessed based on simulations and experiments. Additionally, the natural frequencies of the stator of the tested SRM were determined by a simulation using the Ansys Maxwell suite. The levels of vibration acceleration generated by the SRM were compared for the considered control methods.

Multi-Junction, Multi-Branch Torsional Vibration in a Geared Rotating System

2000 ◽  
Author(s):  
Qing Ke Yuan ◽  
David Y. Yao
Keyword(s):  
Torsional Vibration ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Design Stage ◽  
Design Parameters ◽  
Analysis Program ◽  
Vibration System ◽  
Rotating System ◽  
Steel Rolling ◽  
Mining Machinery

Abstract A multi-junction, multi-branch torsional vibration system is often found in a geared rotating system. This is an important part in many types of machinery, such as mining machinery, petroleum machinery, steel rolling machinery and automobiles. If the design parameters of the system are improper, there will be serious torsional vibration, which will cause noticeable sound disturbances, severe shakings, and component fatigue problems. Analyzing and pre-estimating critical speeds or torsional natural frequencies and mode shapes of the vibration systems in the design stage is very important to avoid future disastrous and costly repairs of the machinery. In this paper, a radical and effective method for calculating natural frequencies and mode shapes of multi-junction, multi-branch torsional vibration systems, has been put forward, a program named MJBTVAP (Multi-Junction, multi-Branch Torsional Vibration Analysis Program) based on this method has been developed, actual problems have been solved.

A Normalized Modal Eigenvalue Approach for Resolving Modal Interaction

1997 ◽  
Vol 119 (3) ◽  
pp. 647-650 ◽  
Author(s):  
M.-T. Yang ◽  
J. H. Griffin
Keyword(s):  
Monte Carlo ◽  
Eigenvalue Problem ◽  
Perturbation Analysis ◽  
Material Properties ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Modal Interaction ◽  
Eigenvalue Approach ◽  
The Difference

Modal interaction refers to the way that the modes of a structure interact when its geometry and material properties are perturbed. The amount of interaction between the neighboring modes depends on the closeness of the natural frequencies, the mode shapes, and the magnitude and distribution of the perturbation. By formulating the structural eigenvalue problem as a normalized modal eigenvalue problem, it is shown that the amount of interaction in two modes can be simply characterized by six normalized modal parameters and the difference between the normalized frequencies. In this paper, the statistical behaviors of the normalized frequencies and modes are investigated based on a perturbation analysis. The results are independently verified by Monte Carlo simulations.

scholarly journals A Normalized Modal Eigenvalue Approach for Resolving Modal Interaction

1996 ◽  
Author(s):  
Ming-Ta Yang ◽  
Jerry H. Griffin
Keyword(s):  
Monte Carlo ◽  
Eigenvalue Problem ◽  
Perturbation Analysis ◽  
Material Properties ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Modal Interaction ◽  
Eigenvalue Approach ◽  
The Difference

Modal interaction refers to the way that the modes of a structure interact when its geometry and material properties are perturbed. The amount of interaction between the neighboring modes depends on the closeness of the natural frequencies, the mode shapes, and the magnitude and distribution of the perturbation. By formulating the structural eigenvalue problem as a normalized modal eigenvalue problem, it is shown that the amount of interaction in two modes can be simply characterized by six normalized modal parameters and the difference between the normalized frequencies. In this paper, the statistical behaviors of the normalized frequencies and modes are investigated based on a perturbation analysis. The results are independently verified by Monte Carlo simulations.

Analytical and Experimental Modal Characteristics of Cylindrical Shells

2005 ◽  
Author(s):  
Basem Alzahabi
Keyword(s):  
Natural Frequency ◽  
Natural Frequencies ◽  
Cylindrical Shells ◽  
Offshore Structures ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Design Stage ◽  
Scaled Model ◽  
Modal Characteristics ◽  
Acoustic Signature

Cylindrical Shells are widely used in many structural designs, such as offshore structures, liquid storage tanks, submarine hulls, and airplane hulls. Most of these structures are required to operate in a dynamic environment. The acoustic signature of submarines is very critical in such high performance structure. Submarines are not only required to sustain very high dynamic loadings at all time, but also being able maneuver and perform their functions under sea without being detected by sonar systems. Reduction of sound radiation is most efficiently achieved at the design stage, and the acoustic signatures may be determined by considering operational scenarios, and modal characteristics. The acoustic signature of submarines is generally of two categories; broadband which has a continuous spectrum; and a tonal noise which has discrete frequencies. Therefore, investigating the dynamic characteristics of cylindrical shells is very critical first step in developing a strategy for modal vibration control for specific operating conditions. Unlike those of beam structure, the lowest natural frequency does not necessarily correspond to the lowest wave index. In fact, the natural frequencies do not fall in ascending order of the wave index in cylindrical shells. Mode shapes associated with each natural frequency are combination of Radial, Longitudinal, and Circumferential modes. In this paper, a scaled model of submarine hull segment under shear diaphragm boundary conditions is analyzed analytically and numerically. Then experimental modal analysis of the scaled model utilizing a fixed response approach was performed to obtain the modal characteristics of the cylindrical shell between 0 and 800 Hz. The cylinder was excited at predetermined points with an impact hammer, while the response was measured using an accelerometer at specified fixed point. Designing a boundary condition that simulate a shear diaphragm is very challenging task by itself. A total of ten natural frequencies were found within that range with their corresponding mode shapes. The experimental data were correlated with those results obtained analytically and numerically using the finite element methods using MSC.NASTRAN software. The results were found to be in excellent agreement.

An Interval-Based Method for Workspace Analysis of Planar Flexure-Jointed Mechanism

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
D. Oetomo ◽  
D. Daney ◽  
B. Shirinzadeh ◽  
J.-P. Merlet
Keyword(s):  
Material Properties ◽  
Design Stage ◽  
Design Criteria ◽  
Pedagogical Approach ◽  
Workspace Analysis ◽  
Wide Range ◽  
Fabrication Tolerances ◽  
Flexure Joints ◽  
Point To Point ◽  
The Given

This paper addresses the problem of certifying the performance of a precision flexure-based mechanism design with respect to the given constraints. Due to the stringent requirements associated with flexure-based precision mechanisms, it is necessary to be able to evaluate and certify the performance at the design stage, taking into account the possible sources of errors such as fabrication tolerances and the modeling inaccuracies in flexure joints. An interval-based method is proposed to certify whether various constraints are satisfied for all points within a required workspace. Unlike the finite-element methods that are commonly used today to evaluate a design, where material properties are used for evaluation on a point-to-point sampling basis, the proposed technique offers a wide range of versatility in the design criteria to be evaluated and the results are true for all continuous values within the certified range of the workspace. This paper takes a pedagogical approach in presenting the interval-based methodologies and the implementation on a planar 3revolute-revolute-revolute (RRR) parallel flexure-based manipulator.

Structural Modification of a Pipe Under Harmonic Excitation Using an Hybrid Numerical/Experimental Method

2011 ◽  
Author(s):  
Charles Bodel
Keyword(s):  
Modal Analysis ◽  
Nuclear Power ◽  
Natural Frequencies ◽  
Harmonic Excitation ◽  
Experimental Modal Analysis ◽  
Point Of View ◽  
Mode Shapes ◽  
Design Stage ◽  
Centrifugal Pumps ◽  
Structural Dynamic

Vibrations generated by centrifugal pumps are difficult to predict at the design stage, for it is hardly possible to accurately determine the natural frequencies of pipes and to avoid coincidences with the blade pass frequency of the pump and its harmonics. One is often led to modify the existing structure, by adding stiffness, mass or damping. This paper illustrates this point on a pipe connected to a pump in a nuclear power plant operated by EDF (E´lectricite´ de France). In October 2010, abnormal vibrations were measured on a thin pipe at the outlet of a pump in a powerplant in France. The French nuclear regulatory commission asked EDF to perform a diagnosis and to define solutions within a few months. EDF/R&D division has used an original method developed in 2004 based on hybrid data, and called LMME-SDM (for Local Model Mode-shapes Expansion Structural Dynamic Modification). The main objective is to define a structure modification able to remove all natural frequencies close to the harmonic excitation. For the purpose of the study, we need a numerical model, which should be fairly correct from a static point of view, but which is not necessarily updated from a dynamic point of view, and an experimental modal analysis carried out under real conditions on the pipe. During the experimental modal analysis, a test of added mass has been carried out so that the method can be validated by comparing the predicted and the observed frequency. This method has already been used in industrial cases in former studies [3], however the study presented here has reached a higher level in complexity. Even if this method is able to give reasonable results compared to measurements, it is close to its limits.

Analytical method for the prediction of natural frequencies of switched reluctance motor based on electromechanical analogy method

2018 ◽  
Vol 37 (1) ◽  
pp. 224-241 ◽  
Author(s):  
Chao Tan ◽  
Honghua Wang ◽  
Ling Chen
Keyword(s):  
Analytical Method ◽  
Natural Frequencies ◽  
Equivalent Stiffness ◽  
Additional Mass ◽  
Stator Core ◽  
Content Type ◽  
Switched Reluctance ◽  
Analogy Method ◽  
Reluctance Motor ◽  
3D Fea

Purpose An improved analytical method for calculating the natural frequencies of a switched reluctance motor (SRM) stator is proposed in this paper. The method is different from traditional analytical methods, which only consider the influence of mass of the stator poles and windings on the natural frequencies of the SRM stator. This paper aims to consider the influence of stiffness and mass of the stator poles and windings simultaneously and reasonably. Design/methodology/approach An innovated analytical method based on the electromechanical analogy method is presented. In the proposed analytical formulae for calculating the natural frequencies, the influence of the windings on natural frequencies is considered by using the springs to simulate the flexible connection between the stator core and windings, and the stator poles are treated as both additional mass and additional equivalent stiffness. Both three-dimensional (3D) finite-element analysis (FEA) and experimental modal analysis results validate the improved method. Findings The influence of the mass and stiffness of stator winding is considered by using the springs to simulate the flexible connection between the stator core and windings, and the stator poles are treated as both additional mass and additional equivalent stiffness. The traditional analytical method only considers the influence of mass. Therefore, the calculation results are comparatively lower than 3D FEA results and may lead to a large error. The 3D FEA and experimental modal analysis confirm that the proposed method has good precision for low-order natural frequency calculation of SRMs. Originality/value An improved analytical method for calculating the natural frequencies of an SRM stator is proposed. Unlike the traditional analytical method, the proposed method can consider the influence of stiffness and mass of the stator poles and windings. This method is valuable for designers to predict the natural frequencies accurately.

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