Updating Rotor-Bearing Finite Element Models

1997 ◽  
Author(s):  
Cristinel Mares ◽  
Cecilia Surace
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Parameters Estimation ◽  
Flexible Rotor ◽  
Estimation Errors ◽  
Rotor Bearing ◽  
Bearing Stiffness ◽  
Measured Frequency Response ◽  
Stiffness And Damping ◽  
The Finite Element Model

Abstract In this paper, the possibility of updating the finite element model of a rotor-bearing system by estimating the bearing stiffness and damping coefficients from a few measured Frequency Response Functions using a Genetic Algorithm is investigated. The issues of identifiability and parameters estimation errors, computational costs and algorithm tuning are addressed. A simulated example of a flexible rotor supported by orthotropic bearings is used for illustrating the method.

Identification of Joint Parameters for a Taper Joint

1989 ◽  
Vol 111 (3) ◽  
pp. 282-287 ◽  
Author(s):  
T. R. Kim ◽  
S. M. Wu ◽  
K. F. Eman
Keyword(s):  
Finite Element ◽  
Experimental Verification ◽  
Joint Stiffness ◽  
Element Model ◽  
Damping Characteristics ◽  
Analysis Technique ◽  
Joint Parameters ◽  
Stiffness And Damping ◽  
Taper Joint ◽  
The Finite Element Model

A new methodology of combining the finite element model of a structure with the results of the experimental modal analysis technique was applied to a tool-holder system with a taper joint to identify its joint stiffness and damping characteristics. The underlying background is briefly introduced followed by an experimental verification of the proposed method.

A Direct Two Response Approach for Updating Analytical Dynamic Models of Structures With Emphasis on Uniqueness

1990 ◽  
Vol 112 (1) ◽  
pp. 107-111 ◽  
Author(s):  
S. R. Ibrahim ◽  
C. Stavrinidis ◽  
E. Fissette ◽  
O. Brunner
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Normal Modes ◽  
Element Model ◽  
Finite Element Models ◽  
Complex Modes ◽  
Structural Responses ◽  
Stiffness And Damping ◽  
The Finite Element Model

An approach, based on utilizing only two sets of structural responses and the enforcement of the conditions for a unique solution, is presented for the updating of Finite Element Models. The responses required can be any two identified normal modes, any two identified complex modes, or two forced harmonic response vectors in the neighborhood of any two natural frequencies of the structure under test. The mass, stiffness, and damping matrices are interactively and simultaneously corrected in a direct noniterative procedure. A uniqueness factor is automatically computed in the procedure to indicate the correctability of the Finite Element Model under consideration. The number of measurement locations is assumed to be less than the number of degrees of freedom of the analytical model. Provisions for completing and smoothing the measured or identified responses are included to reduce the effects of measurement noise and identification error. Preliminary results on simple models are presented in support of the proposed technique.

Development and Experimental Evaluation of a Vehicle Rear Suspension Vibration Model

2002 ◽  
Author(s):  
Shung H. Sung ◽  
Donald J. Nefske ◽  
Douglas A. Feldmaier ◽  
Spencer J. Doggett
Keyword(s):  
Finite Element ◽  
Dynamic Stiffness ◽  
Element Model ◽  
Vibration Response ◽  
Test Fixture ◽  
Rear Suspension ◽  
Vibration Model ◽  
Measured Frequency Response ◽  
Suspension Model ◽  
Stiffness And Damping

A finite-element model of a vehicle rear suspension is developed and experimentally evaluated for predicting the vibration response of the rear suspension to 300 Hz. The suspension model is developed from ten major component finite-element models that were individually correlated to 300 Hz prior to assembly. The bushing and isolator connections between the components are represented using measured dynamic stiffness and damping rates, and a modal tire model is used to represent the tire-wheel assembly. Shaker excitation tests were conducted with the rear suspension supported in a specially designed test fixture to obtain the measured vibration response of the suspension. Comparisons are made of the predicted and measured frequency response functions (FRFs) and modes to experimentally assess the accuracy of the suspension model to 300 Hz. The accuracy of a traditional rigid-link rear suspension model is also assessed.

scholarly journals Experimental and Numerical Investigations of a Flexible Rotor on Flexible Bearing Supports

2005 ◽  
Vol 2005 (3) ◽  
pp. 179-189 ◽  
Author(s):  
J.-J. Sinou ◽  
C. Villa ◽  
F. Thouverez
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Flexible Rotor ◽  
Rolling Bearings ◽  
Campbell Diagram ◽  
Static Tests ◽  
Flexible Supports ◽  
Measured Frequency Response ◽  
Rotor Dynamic

The main goal of this paper is to study, numerically and experimentally, the effects of the bearing support flexibility on the rotor dynamic and the first forward and backward critical speeds. The test rig which is used in this study has been developed and built at the École Centrale de Lyon (France). This flexible rotor, supported by two rolling bearings on flexible supports, is used for three configurations of the flexible supports. The support characteristics are determined experimentally by performing static tests. Moreover, a finite element model of this flexible rotor is presented which consists of a rigid disk on a flexible shaft supported by two bearing supports. On the basis of measured frequency response functions for various rotational speeds, eigenfrequencies and the associated Campbell diagram from the numerical model and the related experimental results for the flexible rotor are discussed. The comparison of these experimental and numerical tests are used in order to update the finite element model and the associated moment stiffness of the two rolling bearings for the three configurations of interest.

Transient Analysis of an Asymmetric Rotor-Bearing System During Acceleration

1992 ◽  
Vol 114 (4) ◽  
pp. 465-475 ◽  
Author(s):  
An-Chen Lee ◽  
Yuan Kang ◽  
Kun-Lung Tsai ◽  
Kuo-Mo Hsiao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Transient Analysis ◽  
Element Model ◽  
Dynamic Equations ◽  
Critical Speeds ◽  
Rotor Bearing ◽  
Asymmetric Rotor ◽  
The Finite Element Model ◽  
Bearing System

This paper deals with the transient vibration of asymmetric rotor systems during acceleration passing through several critical speeds at which synchronous or super-harmonic resonance occurs. The dynamic equations of the rotor-bearing system are formulated by the finite element model and the resulting dynamic equations are time-varying due to the effects of acceleration and asymmetry. In the formulation, a Timoshenko beam element is employed to simulate the rotating shaft and Eulerian angles are used to describe the orientations of the shaft element and disk. The numerical integration scheme for transient analysis is generated from the finite element model. Numerical examples are presented to illustrate (1) the effects of acceleration on peak amplitude and speed at which the peak occurs as the system passes through critical speeds, (2) the optimal acceleration process, which can be obtained by minimizing the peak response and the period of acceleration, (3) the speed regions where the transient instability exists.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Analysis of Hydroelectric Unit’s Upper Bracket Based on Test and FEM

2014 ◽  
Vol 721 ◽  
pp. 131-134
Author(s):  
Mi Mi Xia ◽  
Yong Gang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Element Analysis ◽  
Hydroelectric Unit ◽  
The Finite Element Analysis ◽  
Strain Rosette ◽  
The Finite Element Model

To research the load upper bracket of Francis hydroelectric unit, then established the finite-element model, and analyzed the structure stress of 7 operating condition points with the ANSYS software. By the strain rosette test, acquired the data of stress-strain in the area of stress concentration of the upper bracket. The inaccuracy was considered below 5% by analyzing the contradistinction between the finite-element analysis and the test, and match the engineering precision and the test was reliable. The finite-element method could be used to judge the stress of the upper bracket, and it could provide reference for the Structural optimization and improvement too.

Analysis of Premium Connection of Connecting and Sealing Ability Loaded by Axial Tensile Loads

2012 ◽  
Vol 268-270 ◽  
pp. 737-740
Author(s):  
Yang Yu ◽  
Yi Hua Dou ◽  
Fu Xiang Zhang ◽  
Xiang Tong Yang
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Tensile Load ◽  
Element Model ◽  
Sealing Ability ◽  
Axial Tensile ◽  
High Level ◽  
Maximum Contact ◽  
Contact Pressures ◽  
The Finite Element Model

It is necessary to know the connecting and sealing ability of premium connection for appropriate choices of different working conditions. By finite element method, the finite element model of premium connection is established and the stresses of seal section, shoulder zone and thread surface of tubing by axial tensile loads are analyzed. The results show that shoulder zone is subject to most axial stresses at made-up state, which will make distribution of stresses on thread reasonable. With the increase of axial tensile loads, stresses of thread on both ends increase and on seal section and shoulder zone slightly change. The maximum stress on some thread exceed the yield limit of material when axial tensile loads exceed 400KN. Limited axial tensile loads sharply influence the contact pressures on shoulder zone while slightly on seal section. Although the maximum contact pressure on shoulder zone drop to 0 when the axial tensile load is 600KN, the maximum contact pressure on seal section will keep on a high level.

The structural optimization of roadheader conical picks based on fatigue life

2018 ◽  
Vol 09 (02) ◽  
pp. 1850013 ◽  
Author(s):  
Zhenguo Lu ◽  
Lirong Wan ◽  
Qingliang Zeng ◽  
Xin Zhang ◽  
Kuidong Gao
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Static Analysis ◽  
Element Model ◽  
Cutting Resistance ◽  
Strength Failure ◽  
New Type ◽  
Conical Picks ◽  
Fatigue Life Analysis ◽  
The Finite Element Model

Conical picks are the key cutting components used on roadheaders, and they are replaced frequently because of the bad working conditions. Picks did not meet the fatigue life when they were damaged by abrasion, so the pick fatigue life and strength are excessive. In the paper, in order to reduce the abrasion and save the materials, structure optimization was carried out. For static analysis and fatigue life prediction, the simulation program was proposed based on mathematical models to obtain the cutting resistance. Furthermore, the finite element models for static analysis and fatigue life analysis were proposed. The results indicated that fatigue life damage and strength failure of the cutting pick would never happen. Subsequently, the initial optimization model and the finite element model of picks were developed. According to the optimized results, a new type of pick was developed based on the working and installing conditions of the traditional pick. Finally, the previous analysis methods used for traditional methods were carried out again for the new type picks. The results show that new type of pick can satisfy the strength and fatigue life requirements.

Analysis of Packer Rubber Mechanics Properties

2014 ◽  
Vol 971-973 ◽  
pp. 380-389
Author(s):  
Jian Ning Wang ◽  
Gang Wu ◽  
Wei Yi Xie ◽  
Xin De Han ◽  
Ming Chao Gang
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Constitutive Model ◽  
Contact Stress ◽  
Theoretical Basis ◽  
Element Model ◽  
Rubber Material ◽  
Bottom Hole ◽  
Sealing Performance ◽  
The Finite Element Model

Abstract: The packer rubber stress in the bottom hole is more complex. Based on constitutive model of the packer rubber material, this paper determines such parameters as model constants, Poisson's ratio of rubber materials and elastic modulus by using experimental method, to build up the finite element model of center tube-rubber cylinder-casing for the purpose of stress analysis. Finally, the distribution regularity of rubber cylinder-casing contact stress and packer setting travel distance with varying loads is concluded. The results can provide the theoretical basis for further analysis of packer rubber sealing performance.

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