scholarly journals Analysis and Experimental Investigation of Vibration Characteristics of Rotary Platform of Hydraulic Excavator under Complex Working Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Tinghao Li ◽  
Fuxiu Liu ◽  
Zhaojun Li ◽  
Mingjin Lu ◽  
Qiulu He
Keyword(s):  
Working Conditions ◽  
Dynamic Characteristics ◽  
Pressure Pulsation ◽  
Vibration Characteristics ◽  
Hydraulic Excavator ◽  
Rotary Platform ◽  
Road Excitation ◽  
Engine Excitation ◽  
Internal Relationships ◽  
Excitation Pressure

The rotary platform is the load-bearing substrate of a hydraulic excavator. The dynamic characteristics of the rotary platform directly affect the reliability and safety of the whole machine of a hydraulic excavator. In this work, the characteristics of the main external excitations acting on the hydraulic excavator such as the engine excitation, pressure pulsation excitation of the piston pump, inertial excitation of the working device, and road excitation are analyzed. The vibration transmission paths under the action of external excitations are ascertained. A vibration test method for the rotary platform of the hydraulic excavator is proposed. The vibration characteristics of the rotary platform under complex working conditions are researched, and the internal relationships between the vibration characteristics of the rotary platform and the engine excitation, pressure pulsation excitation of the piston pump, and road excitation are analyzed experimentally. The results show that the rotary platform is subjected to different excitations when it is under different working conditions. Moreover, the internal relationships between the dynamic characteristics of the rotary platform and the external excitation characteristics can be discovered by analyzing the vibration signals of the rotary platform, and the dynamic characteristics of the whole machine of the hydraulic excavator can be deeply studied based on the vibration characteristics of the rotary platform.

Dynamic Characteristics Analysis for the Headstock of a Vertical Machining Center

2016 ◽  
Vol 836-837 ◽  
pp. 348-358
Author(s):  
Zhe Li ◽  
Song Zhang ◽  
Yan Chen ◽  
Peng Wang ◽  
Ai Rong Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Numerical Control ◽  
Vibration Test ◽  
Machining Accuracy ◽  
Modal Test ◽  
Machining Center ◽  
Characteristics Analysis ◽  
Nc Machine

Dynamic characteristics of numerical control (NC) machine tools, such as natural frequency and vibration property, directly affect machining efficiency and finished surface quality. In general, low-order natural frequencies of critical components have significant influences on machine tool’s performances. The headstock is the most important component of the machine tool. The reliability, cutting stability, and machining accuracy of a machining center largely depend on the structure and dynamic characteristics of the headstock. First, in order to obtain the natural frequencies and vibration characteristics of the headstock of a vertical machining center, modal test and vibration test in free running and cutting conditions were carried out by means of the dynamic signal collection and analysis system. According to the modal test, the first six natural frequencies of the headstock were obtained, which can not only guide the working speed, but also act as the reference of structural optimization aiming at frequency-shift. Secondly, by means of the vibration test, the vibration characteristics of the headstock were obtained and the main vibration sources were found out. Finally the corresponding vibration reduction plans were proposed in this paper. That provides the reference for improving the performance of the overall unit.

Study on Flow-Induced Vibration Characteristics of Hydraulic Hoist of Large-Span Upwelling Radial Steel Gate

2011 ◽  
Vol 117-119 ◽  
pp. 241-246
Author(s):  
Zhen Hai Gao ◽  
Gen Hua Yan ◽  
Peng Liu ◽  
Fa Zhan Chen ◽  
Fei Ming Lv
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Flow Induced Vibration ◽  
Structural Dynamic ◽  
Large Span ◽  
Response Characteristics ◽  
Lever Action ◽  
Structural Dynamic Characteristics ◽  
Steel Gate

In this paper we conduct study on flow-induced vibration of large-span upwelling radial steel Gate and its hydraulic hoist. Place an emphasis on vibration response characteristics under two working conditions of diversion and drainage, which proves the safety of hydraulic hoist gate vibration caused by gate vibration. Firstly, we study on dynamic characteristics of fluid-structure interaction of association system of gate and start and stop lever, reveals the discipline of the effect fluid having on structural dynamic characteristics. On this basis, flow-induced vibration characteristics under two conditions of with and without start and stop lever action considered. The results indicate that the gate vibration response with hydraulic hoist used decreases, which explains start and stop lever has certain effect of restraining vibration on gate vibration. In addition, under the working condition of drainage the vibration magnitude of start and stop lever is smaller than that of gate body, which explains there is damping action during transference of gate vibration through start and stop lever. The results find out that on the assumption of optimized gate structure and hydraulic arrangement, it is practicable, safe and reliable to adopt hydraulic hoist. The achievement has directive significance on similar projects construction in the future

The Application of Electrode Design in Vibrating Piezoceramic Plate for Energy Harvesting System

2013 ◽  
Author(s):  
Yu-Hsi Huang ◽  
Ching-Kong Chao ◽  
Wan-Ting Chou
Keyword(s):  
Energy Harvesting ◽  
Dynamic Characteristics ◽  
Electromechanical Coupling ◽  
Coupling Efficiency ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Experimental Measurements ◽  
Piezoceramic Plate ◽  
Resonant Frequencies ◽  
Energy Harvesting System

The energy harvesting system of piezoceramic plate is studied on the electrode configuration to improve the electromechanical transferring efficiency. The piezoceramic plate is used to perform the vibration characteristics by experimental measurements and finite element method (FEM). Thereafter, the dynamic characteristics and the electromechanical coupling efficiency of the piezoelectric energy harvesting system are studied by the electrode design method of the piezoceramic plate. Several experimental techniques are used to measure the dynamic characteristics of piezoceramic plate. First, the full-filed optical technique, amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI), can measure simultaneously the resonant frequencies and mode shapes for out-of-plane and in-plane vibrations. Second, the pointwisely measuring system, laser Doppler vibrometer (LDV), can obtain resonant frequencies by dynamic signal swept-sine analysis. Third, the correspondent in-plane resonant frequencies and anti-resonant frequencies are obtained by impedance analysis. The experimental results of vibration characteristics are verified with numerical calculations. Besides the dynamic characteristics of piezoceramic plates are analyzed in converse piezoelectric effect, the direct piezoelectric effect of piezoceramic plates are excited by shaker to generate the electric voltage. It has excellent consistence between resonant frequencies and mode shapes on the vibration characteristics by experimental measurements and finite element numerical calculations. In this study, the Electrical Potential Gradient (EPG) calculated by FEM is proposed to evaluate the electromechanical coupling efficiency of piezoceramic plate on the specific vibration mode. The correspondent electrode configuration, which is designed by EPG, can produce the best electromechanical transfer both in direct and converse piezoelectric effects. It is concluded that the vibration characteristics of piezoelectric materials have excellent consistence determined by experimental measurements and FEM.

Numerical study on instantaneous radial force of a centrifugal pump for different working conditions

2019 ◽  
Vol 37 (2) ◽  
pp. 458-480
Author(s):  
Xiaoqi Jia ◽  
Sheng Yuan ◽  
Zuchao Zhu ◽  
Baoling Cui
Keyword(s):  
Numerical Simulation ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Working Conditions ◽  
Flow Rate ◽  
Pressure Pulsation ◽  
Radial Force ◽  
Leakage Rate ◽  
Content Type ◽  
Three Components

Purpose Instantaneous radial force induced from unsteady flow will intensify vibration noise of the centrifugal pump, especially under off-design working conditions, which will affect safety reliability of pump operation in severe cases. This paper aims to conduct unsteady numerical computation on one centrifugal pump; thus, unsteady fluid radial force upon the impeller and volute is obtained, so as to study the evolution law of instantaneous radial force, the internal relationship between radial force and pressure pulsation, the relationship among each composition of radial force that the impeller received and the influence of leakage rate of front and back chamber on radial force. Design/methodology/approach The unsteady numerical simulation with SST k-ω turbulence model was carried out for a low specific-speed centrifugal pump using computational fluid dynamics codes FLUENT. The performance tests and pressure tests were conducted by a closed loop system. The performance curves and the pressure distribution from numerical simulation agree with that of the experiment conducted. The unsteady pressure distributions and the instantaneous radial forces induced from unsteady flow were analyzed under different flow rates. Contribution degrees of three components of the radial force on the impeller and the relation between the radial force and leakage rate were analyzed. Findings Radial force on the volute and pressure pulsation on the volute wall have the same distribution tendency, but in contrast to the distribution trend of the radial force on the impeller. In the component of radial force that the impeller received, radial force on the blade accounts for the main position. With the decrease of flow rate, ratio of the radial force on front and back casings will be increased; under large flow rate, vortex and flow blockage at volute section will enhance the pressure and radial force fluctuation greatly, and the pulsation degree may be much more intense than that of a smaller flow rate. Originality/value This paper revealed the relation of the radial force and the pressure pulsation. Meanwhile, contribution degrees of three components of the radial force on the impeller under different working conditions as well as the relation between the radial force and leakage rate of front and rear chambers were analyzed.

Study on Trispectrum Characteristics of MR Damper in Vibration Processes

2011 ◽  
Vol 211-212 ◽  
pp. 285-289
Author(s):  
Fu Sen Wu ◽  
Yi Jian Huang ◽  
Shan Xu
Keyword(s):  
Time Series ◽  
Working Conditions ◽  
Dynamic Characteristics ◽  
Mr Damper ◽  
Ar Model ◽  
Vibration Process ◽  
New Type ◽  
Non Gaussian ◽  
Working Parameters ◽  
Optimum Working

In order to find out a new type of MR damper for block making machine, the signals of displacement in the vibration process during the test are collected and the time series AR model of trispectrum for analyzing the dynamic characteristics of the MR damper is built. It turns out that , in different working conditions, slices of trispectrum are applied to obtain the signal’s non-Gaussian, nonlinear amplitude-frequency characteristics which are very important for us to select the optimum working parameters of the MR damper.

Research on Dynamic Characteristics of Anti-Reverse Valve for Hydraulic Excavator Rotary Motor

2013 ◽  
Vol 871 ◽  
pp. 290-295
Author(s):  
Yan Lei Luo ◽  
Cong Guo Xu ◽  
Qiu Yan Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Hydraulic System ◽  
Working Condition ◽  
Great Influence ◽  
Hydraulic Excavator ◽  
Middle Chamber ◽  
Working Principle ◽  
The Impact ◽  
Rotary Motor ◽  
Amesim Simulation

Hydraulic excavator slewing system is an important component of the excavator and its core-component is the rotary motor. When the rotary hydraulic system starts, stops, and reciprocating works, dynamic characteristic of rotary motor anti-reverse valve has a great influence for working condition of the whole system. Through researching working principle of hydraulic system anti-reverse valve, establish dynamic mathematical model of anti-reverse valve, analyze dynamic response of the model, and get the theoretical foundation of the impact of anti-reverse valve middle chamber throttle opening on hydraulic system. According to the actual working condition of the excavator slewing hydraulic system, establish the system AMESim simulation model, take different parameters of the anti-reverse valve throttle opening, conduct simulation and analysis of the anti-reverse valve characteristics, and validate throttle opening has a great influence on dynamic characteristics of the hydraulic system.

Vibration Characteristics Analysis of an Aero-Engine Turbine Blade

2012 ◽  
Vol 487 ◽  
pp. 894-897
Author(s):  
Wei Qiang Zhao ◽  
Yong Xian Liu ◽  
Mo Wu Lu ◽  
Qing Jun Guo
Keyword(s):  
Optimal Design ◽  
Turbine Blade ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Vibration Characteristic ◽  
Analysis Method ◽  
Aero Engine ◽  
Characteristics Analysis

This paper introduces the FEA method for a certain type of aero-engine turbine blade and makes a vibration characteristics analysis to this aero-engine turbine blade based on this method. The vibration characteristic of this aero-engine turbine blade is studied and the natural modal of the turbine blade is calculated based on UG software. The first six natural frequencies and mode shapes are given. According to the analysis results the dynamic characteristics of the blade are discussed. The analysis method and results in this paper can be used for further study on optimal design and vibration safety verification for the blade.

Simulation Research on Test Platform of Wave Energy Hydraulic Conversion System in Laboratory Based on AMEsim

2012 ◽  
Vol 220-223 ◽  
pp. 1711-1714
Author(s):  
Shou Jun Wang ◽  
Qi Qiang Liu
Keyword(s):  
Power Generation ◽  
Energy Loss ◽  
Working Conditions ◽  
Dynamic Characteristics ◽  
Wave Energy ◽  
Wave Power ◽  
Simulation Research ◽  
Factors Affecting ◽  
Test Platform ◽  
Conversion System

The test platform of wave energy hydraulic conversion system is built up in the laboratory, which used to analyze the factors affecting the efficiency of wave power generation under the premise of simulating actual working conditions at sea with the maximum extent possible. This paper described the basic components and established the AMEsim model of the test platform, while we simulated the test platform based on AMEsim and researched the dynamic characteristics of the test platform and analyzed the energy loss of the system.

Study on Static and Dynamic Characteristics of Load-Sensing and Pressure-Compensated Directional Control Valve

2013 ◽  
Vol 753-755 ◽  
pp. 2693-2699 ◽  
Author(s):  
Rui Lin Feng ◽  
Jian Hua Wei ◽  
Jin Hui Fang
Keyword(s):  
Transfer Function ◽  
Working Conditions ◽  
Dynamic Characteristics ◽  
Pressure Coefficient ◽  
Control Valve ◽  
Parameters Optimization ◽  
Static And Dynamic Characteristics ◽  
Load Sensing ◽  
Directional Control ◽  
Directional Control Valve

This study presents the static and dynamic characteristics of load-sensing and pressure-compensated directional control valve under the working conditions. A mathematical model is developed, two types of working conditions are presented through the static work point calculation. The static characteristic is analyzed by simulation, and the conclusion is validated by experiments. Solution procedure of the flow gain transfer function and flow-pressure coefficient transfer function is detailed introduced based on the above static computation, and their dynamic characteristic is analyzed by using Bode diagram. Finally, three types of compensatory modes are proposed, which provides very useful value and significance for the hydraulic component or system design and parameters optimization.

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