The Mechanism Revealing and Law Explorating for the Nonlinear Response of Blade Disk Rotor System Under the Coupling Effects of Crack and Aerodynamic Force

2021 ◽  
Author(s):  
Jinsong Yang ◽  
Jingsong Xie ◽  
Tiantian Wang ◽  
Fei Yang ◽  
Jinglong Chen
Keyword(s):  
Number Theory ◽  
Numerical Solution ◽  
Dynamic Model ◽  
Aerodynamic Force ◽  
Rotor System ◽  
Kinematics And Dynamics ◽  
Response Mechanism ◽  
Coupling Effects ◽  
Response Characteristics ◽  
Blade Crack

Abstract Blade disk rotor system is a typical structure of industrial equipments such as aeroengines and gas turbines. The research on the response characteristics and mechanism of the system under the coupling effects of aerodynamic force and blade crack is of great significance to the interpretation of vibration phenomena and diagnosis of faults. From the numerical solution based response characteristic analysis to the kinematics and dynamics based essential response mechanism revealing, from the model based special case study to the Number Theory based general law establishing, in this paper, the response mechanism of blade disk rotor system under the coupling effects of crack and aerodynamic force is studied comprehensively and deeply. Firstly, a simplified dynamic model of typical blade disk rotor system is constructed by using the classical continuous parameter modeling method. Based on the dynamic model, for two structural forms of moving and stationary blades, the typical characteristics of vibration response under the actions of aerodynamic force and blade crack are analyzed by means of numerical solution. Then, from the perspective of kinematics and dynamics, the internal mechanism between the vibration responses and the excitations are revealed. Finally, based on Number Theory, the response characteristics and mechanism of typical structures are summarized, and the general laws of responses with general structural forms are established.

scholarly journals Dynamic Modelling and Response Characteristics of a Magnetic Bearing Rotor System With Auxiliary Bearings

1995 ◽  
Author(s):  
April M. Free ◽  
George T. Flowers ◽  
Victor S. Trent
Keyword(s):  
Dynamic Modelling ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Rolling Element Bearing ◽  
Test Facility ◽  
Iron Core ◽  
Critical Feature ◽  
Response Characteristics ◽  
Rolling Element ◽  
Auxiliary Bearing

Abstract Auxiliary bearings are a critical feature of any magnetic bearing system. They protect the soft iron core of the magnetic bearing during an overload or failure. An auxiliary bearing typically consists of a rolling element bearing or bushing with a clearance gap between the rotor and the inner race of the support. The dynamics of such systems can be quite complex. It is desired to develop a rotordynamic model which describes the dynamic behavior of a flexible rotor system with magnetic bearings including auxiliary bearings. The model is based upon an experimental test facility. Some simulation studies are presented to illustrate the behavior of the model. In particular, the effects of introducing sideloading from the magnetic bearing when one coil fails is studied. These results are presented and discussed.

Rotorcraft control response using linearised and non-linear flight dynamic models with different inflow models

2017 ◽  
Vol 121 (1238) ◽  
pp. 553-575 ◽  
Author(s):  
T. Sakthivel ◽  
C. Venkatesan
Keyword(s):  
Dynamic Model ◽  
Dynamic Models ◽  
Model Identification ◽  
Flight Test ◽  
Step Size ◽  
Response Characteristics ◽  
Wide Range ◽  
Non Linear ◽  
Steady Level ◽  
Control Response

ABSTRACTThe aim of the present study is to develop a relatively simple flight dynamic model which should have the ability to analyse trim, stability and response characteristics of a rotorcraft under various manoeuvring conditions. This study further addresses the influence of numerical aspects of perturbation step size in linearised model identification and integration timestep on non-linear model response. In addition, the effects of inflow models on the non-linear response are analysed. A new updated Drees inflow model is proposed in this study and the applicability of this model in rotorcraft flight dynamics is studied. It is noted that the updated Drees inflow model predicts the control response characteristics fairly close to control response characteristics obtained using dynamic inflow for a wide range of flight conditions such as hover, forward flight and recovery from steady level turn. A comparison is shown between flight test data, the control response obtained from the simple flight dynamic model, and the response obtained using a more detailed aeroelastic and flight dynamic model.

Dynamic Behavior Analysis of Three-Span Rotor-Bearing System with Rub-Impact Fault

2012 ◽  
Vol 460 ◽  
pp. 160-164 ◽  
Author(s):  
Song He Zhang ◽  
Yue Gang Luo ◽  
Bin Wu ◽  
Bang Chun Wen
Keyword(s):  
Nonlinear Dynamics ◽  
Behavior Analysis ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Rotor System ◽  
System Response ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System ◽  
Main Influence

The dynamic model of the three-span rotor-bearing system with rub-impact fault was set up. The influence to nonlinear dynamics behaviors of the rotor-bearing system that induced by rub-impact of one disc, two discs and three discs were numerically studied. The main influence of the rotor system response by the rub-impact faults are in the supercritical rotate speed. There are mutations of amplitudes in the responses of second and third spans in supercritical rotate speed when rub-impact with one disc, and there are chaotic windows in the response of first span, and jumping changes in second and third spans when rub-impact with two or three discs.

Kinematics and Dynamics Modeling of a New 4-DOF Cable-Driven Parallel Manipulator

2013 ◽  
pp. 249-265
Author(s):  
Hamoon Hadian ◽  
Yasser Amooshahi ◽  
Abbas Fattah
Keyword(s):  
Dynamic Model ◽  
Parallel Manipulator ◽  
Joint Space ◽  
Kinematics And Dynamics ◽  
Dynamics Modeling ◽  
Kinematic Constraint ◽  
Control Scheme ◽  
Minimum Number ◽  
Dynamical Properties ◽  
Computed Torque

This paper addresses the kinematics and dynamics modeling of a 4-DOF cable-driven parallel manipulator with new architecture and a typical Computed Torque Method (CTM) controller is developed for dynamic model in SimMechanics. The novelty of kinematic architecture and the closed loop formulation is presented. The workspace model of mechanism’s dynamic is obtained in an efficient and compact form by means of natural orthogonal complement (NOC) method which leads to the elimination of the nonworking kinematic-constraint wrenches and also to the derivation of the minimum number of equations. To verify the dynamic model and analyze the dynamical properties of novel 4-DOF cable-driven parallel manipulator, a typical CTM control scheme in joint-space is designed for dynamic model in SimMechanics.

Modeling and Grasp Stability Analysis for Object Manipulation by Soft Rolling Fingertips

2014 ◽  
Vol 11 (03) ◽  
pp. 1450020 ◽  
Author(s):  
John Fasoulas ◽  
Michael Sfakiotakis
Keyword(s):  
Stability Analysis ◽  
Dynamic Model ◽  
Object Manipulation ◽  
Kinematics And Dynamics ◽  
Control Law ◽  
Two Dimensional ◽  
Orientation Control ◽  
Grasp Stability ◽  
Different Types ◽  
General Dynamic

This paper presents a general dynamic model that describes the two-dimensional grasp by two robotic fingers with soft fingertips. We derive the system's kinematics and dynamics by incorporating rolling constraints that depend on the deformation and on the rolling distance characteristics of the fingertips' material. We analyze the grasp stability at equilibrium, and conclude that the rolling properties of the fingertips can play an important role in grasp stability, especially when the width of the grasped object is small compared to the radius of the tips. Subsequently, a controller, which is based on the fingertips' rolling properties, is proposed for stable grasping concurrent with object orientation control. We evaluate the dynamic model under the proposed control law by simulations and experiments that make use of two different types of soft fingertip materials, through which it is confirmed that the dynamic model can successfully capture the effect of the fingertips' deformation and their rolling distance characteristics. Finally, we use the dynamic model to demonstrate by simulations the significance of the fingertips' rolling properties in grasping thin objects.

scholarly journals Response analysis of random base excitation ona magnetic bearing rotor system

2019 ◽  
Vol 293 ◽  
pp. 04004
Author(s):  
Jinping Chen ◽  
Li Zhang ◽  
Yanyan Luo ◽  
Haining Zhang ◽  
Jun Liu
Keyword(s):  
Collision Detection ◽  
Random Excitation ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Response Analysis ◽  
Random Response ◽  
Practical Application ◽  
External Disturbances ◽  
Response Characteristics ◽  
Auxiliary Bearing

The magnetic bearing-rotor system is subject to various external disturbances in practical application. Under certain control conditions, the random response characteristics of the magnetic bearing-rotor system are a particular concern. This paper analyzes the response characteristics of base of the magnetic bearing subjected to acceleration random excitation in the horizontal direction. First, the magnetic bearing-rotor system model is deduced. Then, the random response of the rotor under acceleration random excitation is derived. The probability of the collision of the rotor between the auxiliary bearing is calculated and the example is given. The paper conclusion provides a theoretical basis for the collision detection and prediction of the magnetic bearing-rotor system.

Dynamic analysis of swivel construction method under multi-variable coupling effects

2019 ◽  
Vol 10 (4) ◽  
pp. 580-598
Author(s):  
Wang Jiawei ◽  
Sun Quansheng
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Static Analysis ◽  
Friction Stress ◽  
Construction Method ◽  
Coupling Effects ◽  
Content Type ◽  
Multiple Factors ◽  
Real State ◽  
Variable Coupling

Purpose Swivel construction is a new bridge construction method, which can minimize the impact on railway and highway traffic. Previous studies were based on single factor and static analysis, which cannot reflect the real state of structures. The purpose of this paper is to establish a dynamic model of the structure and to analyze the situation under multi-variable coupling effects to accurately simulate the real state of the structure. Design/methodology/approach Finite element software ANSYS was used to establish dynamic model of turntable structure and then to analyze the effects of multiple factors on total stress, friction stress and slipping distance of the turntable structure. Findings It is concluded that the unbalanced weight and radius of spherical hinges have great influence on the turntable structure, so the design should be strictly considered. Friction stress and angular acceleration have little effect on the turntable structure. Originality/value This paper provides simulation of the whole process of swivel construction method. Whereas previous studies focused on static analysis, this paper focuses on the dynamic analysis of swivel construction method. The mechanics of the swivel structure under multiple factors was analyzed. According to the analysis results, the design parameters of the turntable structure are optimized.

Robust Control of the Elastodynamic Vibrations of a Flexible Rotor System With Discontinuous Friction

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Mansour Karkoub
Keyword(s):  
Dynamic Model ◽  
Design Process ◽  
Nonlinear Models ◽  
Control Design ◽  
Rotor System ◽  
Control Technique ◽  
Flexible Rotor ◽  
Highly Nonlinear ◽  
Modeling Errors ◽  
The Difference

The work presented here deals with the control of a flexible rotor system using the μ-synthesis control technique. This technique allows for the inclusion of modeling errors in the control design process in terms of uncertainty weights. The dynamic model of the rotor system, which includes discontinuous friction, is highly nonlinear and has to be linearized around an operating point in order to use μ-synthesis. The difference between the linear and nonlinear models is characterized in terms of uncertainty weights and included in the control design process. The designed controller is robust to uncertainty in the dynamic model, spillover, actuator uncertainty, and noise. The theoretical findings of the μ-synthesis control design are validated through simulations and the results are presented and discussed here.

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