Dynamic Reliability Evaluation of Pressure Pulsation for Hydraulic Power Pipelines

2010 ◽  
Vol 139-141 ◽  
pp. 2436-2439
Author(s):  
Wei Liu ◽  
Hang Shan Gao ◽  
Zhu Feng Yue
Keyword(s):  
Failure Criterion ◽  
Design Method ◽  
Dynamic Pressure ◽  
Pressure Pulsations ◽  
Hydraulic Power ◽  
Dynamic Reliability ◽  
Output Pressure ◽  
Fatigue Damage Accumulation ◽  
First Passage Failure ◽  
Execution Unit

The pressure pulsations inner the hydraulic power pipelines not only deteriorate the precision of execution unit, but also bring on vibration, noise or other troubles in hydraulic device. In this paper, the output pressure pulsations were treaded as a stationary random process approximately. The mean square deviation of dynamic stress under the pumping source white noise exciting was calculated based on frequency responses. The first-passage failure criterion and fatigue damage accumulation failure criterion were adopted to analyze the dynamic pressure reliability respectively, and the relation of amplitude pulsations and the pipelines reliability was obtained. The results indicated that the preventative design method of below10% of rated pressure did not meet the security specification of the hydraulic power unit.

scholarly journals Inner Damping of Water in Conduit of Hydraulic Power Plant

2021 ◽  
Vol 13 (13) ◽  
pp. 7125
Author(s):  
Daniel Himr ◽  
Vladimír Habán ◽  
David Štefan
Keyword(s):  
Power Plant ◽  
Operating Conditions ◽  
Mathematical Apparatus ◽  
Pressure Pulsations ◽  
Hydraulic Power ◽  
Economic Operation ◽  
Compression And Expansion ◽  
Rotor Stator Interaction ◽  
Start Ups

The operation of any hydraulic power plant is accompanied by pressure pulsations that are caused by vortex rope under the runner, rotor–stator interaction and various transitions during changes in operating conditions or start-ups and shut-downs. Water in the conduit undergoes volumetric changes due to these pulsations. Compression and expansion of the water are among the mechanisms by which energy is dissipated in the system, and this corresponds to the second viscosity of water. The better our knowledge of energy dissipation, the greater the possibility of a safer and more economic operation of the hydraulic power plant. This paper focuses on the determination of the second viscosity of water in a conduit. The mathematical apparatus, which is described in the article, is applied to data obtained during commissioning tests in a water storage power plant. The second viscosity is determined using measurements of pressure pulsations in the conduit induced with a ball valve. The result shows a dependency of second viscosity on the frequency of pulsations.

scholarly journals RBF Neural Network Backstepping Sliding Mode Adaptive Control for Dynamic Pressure Cylinder Electrohydraulic Servo Pressure System

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Pan Deng ◽  
Liangcai Zeng ◽  
Yang Liu
Keyword(s):  
Neural Network ◽  
Adaptive Control ◽  
Sliding Mode ◽  
Model Simulation ◽  
Rbf Neural Network ◽  
Dynamic Pressure ◽  
Adaptive Controller ◽  
Pressure System ◽  
Output Pressure ◽  
Pressure Cylinder

According to the hydraulic principle diagram of the subgrade test device, the dynamic pressure cylinder electrohydraulic servo pressure system math model and AMESim simulation model are established. The system is divided into two parts of the dynamic pressure cylinder displacement subsystem and the dynamic pressure cylinder output pressure subsystem. On this basis, a RBF neural network backstepping sliding mode adaptive control algorithm is designed: using the double sliding mode structure, the two RBF neural networks are used to approximate the uncertainties in the two subsystems, provide design methods of RBF sliding mode adaptive controller of the dynamic pressure cylinder displacement subsystem and RBF backstepping sliding mode adaptive controller of the dynamic pressure cylinder output pressure subsystem, and give the two RBF neural network weight vector adaptive laws, and the stability of the algorithm is proved. Finally, the algorithm is applied to the dynamic pressure cylinder electrohydraulic servo pressure system AMESim model; simulation results show that this algorithm can not only effectively estimate the system uncertainties, but also achieve accurate tracking of the target variables and have a simpler structure, better control performance, and better robust performance than the backstepping sliding mode adaptive control (BSAC).

An Experimental Study of Soft Rock Roadway with Anchored Support Structure Based on Nested Mechanical Analysis Model

2011 ◽  
Vol 90-93 ◽  
pp. 277-283
Author(s):  
Fu Sheng Liu ◽  
Gang Gang Dong ◽  
Su Hua Wang ◽  
Shao Jie Wang ◽  
Yang Song
Keyword(s):  
Design Method ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Soft Rock ◽  
Mechanical Analysis ◽  
Analysis Model ◽  
Support Structure ◽  
Three Dimensional Finite Element ◽  
Soft Rock Roadway ◽  
Rock Roadway

This paper chooses anchored support engineering of ore dynamic pressure soft rock roadway Qinan, Huaibei city as an example, and with the help of nested mechanical analysis model of anchored support structure, the paper analyzes the range of elastoplasticity, the range of anchor note area, stress and displacement of original rocks of the reinforced project, and simulates three-dimensional finite element numerical and underwent engineering detection of the project. Practicality and validity of quantitative control design method of anchored support structure are proved by comparing the theoretic research, calculation results, and field measurement results.

An Evaluation of the Jenike Bunker Design Method

1973 ◽  
Vol 95 (1) ◽  
pp. 48-54 ◽  
Author(s):  
H. Wright
Keyword(s):  
Iron Ore ◽  
Transition Point ◽  
Design Method ◽  
Dynamic Pressure ◽  
Operating Costs ◽  
Variable Geometry ◽  
Iron Ores ◽  
Flow Blockage ◽  
Correct Design

Flow blockage in steelworks bunkers is a major source of trouble. The correct design of bunkers to ensure flow would result in reduced capital and operating costs. The Jenike method of bunker design, which claims a solution to this problem, has been critically examined for a range of iron ores using a variable-geometry wedge-shaped bunker. The main conclusion from these experiments is that the Jenike method is valid for dynamic pressure conditions and even shows some over-design. Further experiments using just one iron ore have confirmed the validity for a conical-shaped bunker under similar pressure conditions. The main limitations of the Jenike design method are as follows: (a) It does not provide a design which can accommodate impact filling. In certain cases, especially with conical bunkers, flow blockage can easily occur and (b) It does not provide a design which can be certain of eliminating arching at the transition point of a bunker with surcharge.

Research on Design Methods and Experiments of the Electro-Hydraulic Power Steering Pump

2014 ◽  
Vol 986-987 ◽  
pp. 1125-1128 ◽  
Author(s):  
Yong Chen ◽  
Jing Jing Xia
Keyword(s):  
Design Method ◽  
Subsequent Development ◽  
Steering System ◽  
Hydraulic Power ◽  
Power Steering ◽  
Electronic Control System ◽  
Hydraulic Steering ◽  
Test Platform ◽  
Pump Test ◽  
Hydraulic Power Steering

In order to improve the performance of vehicle steering system and reduce the system energy consumption, the structure and operation principle of an electro-hydraulic power steering (EHPS) system with a electro-hydraulic steering pump are described, on this basis, with the function requirement of steering system, and by using vehicle design and fluid drive theory, the design method of this electro-hydraulic steering pump and its matching with the vehicle are presented. Through building electro-hydraulic steering pump test platform to test its performance parameters, the results prove the correctness and effectiveness of this kind of design method, provide the basis for subsequent development of the electronic control system.

A New Approach for Dynamic Reliability Analysis of Offshore Platforms

2003 ◽  
Author(s):  
Wei-Liang Jin
Keyword(s):  
Reliability Analysis ◽  
Failure Criterion ◽  
Offshore Platform ◽  
Seismic Action ◽  
Offshore Platforms ◽  
Structural Dynamic ◽  
Jacket Platform ◽  
Dynamic Reliability ◽  
Strength Failure ◽  
Offshore Jacket Platform

The theoretical framework of a new dynamic reliability analysis approach for offshore jacket platforms is constructed in this paper. In this approach, the structural dynamic reliability analysis integrates the structural dynamic response theory with the random sampling technique on stochastic variables of the platform. Offshore jacket platform is assumed as a shear type one and is controlled by its horizontal resistance bearing capacity. The failure criterion of offshore platform dynamic reliability includes two aspects: strength failure criterion and deformation failure criterion. The strength failure criterion is based on the double-damage criterion of ultimate dynamic analysis, while the deformation failure criterion depends on the requirement of the offshore oil production. The dynamic reliability formula of offshore platforms is gained on the basis of the first crossing theory. In this paper, uncertainties of offshore jacket platform dynamic reliability subjected to wave hydrodynamic and seismic action are studied respectively. The probabilistic distributions and its statistical characteristics of wave hydrodynamic and seismic action are given on the base of limit bearing state of the platform. The dynamic reliability analysis of an offshore platform W11-4C, located at the gulf of Weizhou, South China Sea, is carried out. Some valuable conclusions are summarized.

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