scholarly journals Synchronization and Stability of Elasticity Coupling Two Homodromy Rotors in a Vibration System

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Yongjun Hou ◽  
Mingjun Du ◽  
Pan Fang ◽  
Yuwen Wang ◽  
Liping Zhang
Keyword(s):  
Theoretical Analysis ◽  
Computer Simulations ◽  
Stability Criterion ◽  
Mechanical Model ◽  
Induction Motors ◽  
Simplified Model ◽  
Vibration System ◽  
Analysis Method ◽  
Lagrange Equations ◽  
Synchronous State

The mechanical model of an elasticity coupling 1-DOF system is proposed to implement synchronization; the simplified model is composed of a rigid body, two induction motors, and a connecting spring. Based on the Lagrange equations, the dynamic equation of the system is established. Moreover, a typical analysis method, the Poincare method, is applied to study the synchronization characteristics, and the balanced equations and stability criterion of the system are obtained. Obviously, it can be seen that many parameters affect the synchronous state of the system, especially the stiffness of the support spring, the stiffness of the connecting spring, and the installation location of the motors. Meanwhile, choose a suitable stiffness of the connecting spring (k), which would play a significant role in engineering. Finally, computer simulations are used to verify the correctness of the theoretical analysis.

scholarly journals Synchronization and Stability of Two Unbalanced Rotors with Fast Antirotation considering Energy Balance

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Yongjun Hou ◽  
Pan Fang
Keyword(s):  
Energy Balance ◽  
Theoretical Analysis ◽  
Differential Equations ◽  
Computer Simulations ◽  
Stability Criterion ◽  
Induction Motors ◽  
Energy Balance Method ◽  
Analytical Analysis ◽  
The Stability ◽  
Vibrating Systems

We consider synchronization and stability of two unbalanced rotors reversely and fast excited by induction motors fixed on an oscillating body. We explore the energy balance of the system and show how the energy is transferred between the rotors via the oscillating body allowing the implementation of the synchronization of the two rotors. An approximate analytical analysis, energy balance method, allows deriving the synchronization condition, and the stability criterion of the synchronization is deduce by disturbance differential equations. Later, to prove the correctness of the theoretical analysis, many features of the vibrating system are computed and discussed by computer simulations. The proposed method may be useful for analyzing and understanding the mechanism of synchronization, stability, and energy balance of similar fast rotation rotors excited by induction motors in vibrating systems.

The Theoretical Analysis of Performance Evaluation Connotation of Rural Highway Projects

2012 ◽  
Vol 204-208 ◽  
pp. 1848-1856
Author(s):  
Wu Gong Wang ◽  
Rong Guo Ma ◽  
Kun Feng ◽  
Guo Hua Liang
Keyword(s):  
Public Finance ◽  
Performance Evaluation ◽  
Theoretical Analysis ◽  
Swot Analysis ◽  
Project Performance ◽  
Analysis Method ◽  
Highway Projects ◽  
Rural Highway ◽  
Analysis Of Performance ◽  
Highway Project

On the basis of defining the concept of rural highway project performance, the necessity of the project performance evaluation of rural highway is analyzed. According to the theories of government's public function, fiduciary responsibilities accountability and public finance, the relation between rural highway and public finance are made researches on. Furthermore,with the application of the demand level theory of Maslow, the interrelationship among objects of the rural highway project performance evaluation is made an analysis of, and on top of that, combined with SWOT analysis method, the demand and goal of rural highway project performance evaluation are put forward.

Vibrations of a Helicopter Rotor-Fuselage System Induced by the Main Rotor Blades in Flight

1955 ◽  
Vol 22 (3) ◽  
pp. 355-360
Author(s):  
M. Morduchow ◽  
S. W. Yuan ◽  
H. Reissner
Keyword(s):  
Theoretical Analysis ◽  
Natural Frequencies ◽  
Rotor Blades ◽  
Helicopter Rotor ◽  
Simplified Model ◽  
Main Rotor ◽  
Numerical Examples ◽  
The Masses

Abstract Based on a simplified model of the hub-fuselage structure, a theoretical analysis is made of the response of the hub and fuselage of a helicopter in flight to harmonic forces transmitted by the rotor blades to the hub both in, and normal to, the plane of rotation. The assumed structure is in the form of a plane framework with masses concentrated at the joints. Simple expressions are derived for the vibration amplitudes of the mass points as functions of the masses and natural frequencies of the hub and the fuselage. The pertinent nondimensional parameters are determined, and simple explicit conditions of resonance are derived. Numerical examples are given to illustrate the results.

scholarly journals Design and installation of vibration testing system for spring mounted model of wing

2015 ◽  
Vol 18 (4) ◽  
pp. 179-187
Author(s):  
Anh Tien Tran ◽  
Nam Ngoc Linh Hoang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Theoretical Analysis ◽  
Testing System ◽  
Vibration System ◽  
Ultrasonic Sensors ◽  
Wing Model ◽  
Suitable Area ◽  
Naca 0015 ◽  
Theoretical Dynamics

This paper presents the design and installation of measuring vibration system in wind tunnel area 1m x 1m. The theoretical analysis of the spring structure in this model help we possible to design a system for wind tunnel by yourself with suitable area, wind speed as well as survey wing model to obtain results desire. This system helps us to observe the oscillation of wing survey by eyes, but to know exactly how wing fluctuates, also the pitching angle of wing, we use ultrasonic sensors to measure the distance variation, will be presented in more detail in the text. At the same time, the article also shows how to make a simple and durable wing model with NACA 0015 airfoil - wing model will be surveyed ranged in system above. The aerodynamic phenomena affect to the vibration of the wing are also mentioned and overcome in the design of the wing. Finally we process the data after measured to see the similarities between the experiment and the theoretical dynamics of aviation.

Experimental Research on Parameters Identification of Dynamic Characteristic for Parallel Machine Tool

2013 ◽  
Vol 300-301 ◽  
pp. 181-184
Author(s):  
Chun Xia Zhu ◽  
Zhi Wen Chen ◽  
Bo Liu ◽  
Jing Wang
Keyword(s):  
Optimal Design ◽  
Theoretical Analysis ◽  
Machine Tool ◽  
Dynamic Characteristic ◽  
Parallel Machine ◽  
Vibration System ◽  
Flexible Coupling ◽  
Vibration Model ◽  
Experiment Method ◽  
Parallel Machine Tool

The dynamic characteristics of parallel 3-TPT machine tool are researched by experiment in this paper. Firstly, modal analysis principle of machine tool was analyzed in theory, and the parameters of dynamic characteristic were identified by theoretical analysis. Then vibration model of parallel machine tool was built and formed vibration system of rigid and flexible coupling for analysis. Then, the modal experiment method and steps were introduced, and the experiment parameters also were identified according to the experiment results. The result dates are showed that the result dates are validated. So the experiment method is feasible by experimental verification, which provides reference for dynamic optimal design.

Improved cyclostationary analysis method based on TKEO and its application on the faults diagnosis of induction motors

2021 ◽  
Author(s):  
Zuolu Wang ◽  
Jie Yang ◽  
Haiyang Li ◽  
Dong Zhen ◽  
Fengshou Gu ◽  
...  
Keyword(s):  
Induction Motors ◽  
Analysis Method ◽  
Faults Diagnosis

scholarly journals Mechanical Respond and Failure Mode of Large Size Honeycomb Sandwiched Composites under In-Plane Shear Load

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4248 ◽  
Author(s):  
Wang ◽  
Wang ◽  
Liu ◽  
Zhang ◽  
Wan ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Shear Strain ◽  
Failure Mode ◽  
Field Distribution ◽  
Shear Failure ◽  
Buckling Load ◽  
Analysis Method ◽  
Plane Shear ◽  
Large Size ◽  
Honeycomb Sandwich

The present work focuses on the in-plane shear respond and failure mode of large size honeycomb sandwich composites which consist of plain weave carbon fabric laminate skins and aramid paper core. A special size specimen based on a typical element of aircraft fuselage was designed and manufactured. A modified in-plane shear test method and the corresponding fixture was developed. Three large size specimens were tested. The distributed strain gauges were used to monitor the mechanical response and ultimate bearing capacity. The results show that a linear respond of displacement and strain appears with the increase of the load. The average shear failure load reaches 205.68 kN with the shear failure occurring on the face sheet, and the maximum shear strain monitored on the composite plate is up to 16,115 με. A combination of theoretical analysis and finite element method (FEM) was conducted to predict the shear field distribution and the overall buckling load. The out-of-plane displacement field distribution and in-plane shear strain field distribution under the pure shear loading were revealed. The theoretical analysis method was deduced to obtain the variation rule of the shear buckling load. A good agreement was achieved among the experiment, theoretical analysis, and FEM results. It can be concluded that the theoretical analysis method is relatively conservative, and the FEM is more accurate in case of deformation and strain. The results predicted by h element and p element methods are very close. The results of the study could provide data support for the comprehensive promotion of the design and application of honeycomb sandwich composites.

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