Multi-objective design optimization of the complete valve system in an adjustable linear hydraulic damper

2010 ◽  
Vol 225 (3) ◽  
pp. 679-699 ◽  
Author(s):  
W L Wang ◽  
X J Yang ◽  
G X Xu ◽  
Y Huang
Keyword(s):  
Design Optimization ◽  
High Speed ◽  
Optimal Result ◽  
Relief Valve ◽  
Valve System ◽  
Hydraulic Damper ◽  
Multi Objective ◽  
Damping Characteristics ◽  
Fitness Value ◽  
Optimization Search

Adjustable linear hydraulic dampers are widely used in high-speed trains to improve their ride comfort and stability, the distinctive damping characteristics of the dampers are intrinsically predetermined by their inner complete valve systems. Therefore, design of the complete valve system parameters for each damper type is of crucial importance. A multi-objective design optimization model for the concept of optimizing both the technical and economic capabilities of a three-valve complete valve system in a hydraulic damper was formulated, based on full damper dynamics modelling. A linear weighted criterion method was used to transform the established multi-objective problem to a single-objective problem, and a computer package employing the genetic algorithm for the optimization search was developed. Implementation of the design optimization was performed, and an optimal result, with about 10.29 per cent improvement of the overall fitness value, was obtained. Simulation results show that the optimal result satisfies all the competing objectives well within the constraints, except for some minor and tolerable tradeoffs in the relief valve response performance. Prototype experiments validated that the prototype dampers have obtained excellent damping characteristics, as expected. Thus, the complete valve system of the hydraulic damper was comprehensively optimized, with respect to both the technical and economic concerns. The approach developed in this work has already been applied to the engineering design of several hydraulic damper products in industry.

Prediction of the in-service performance of a railway hydraulic damper

2016 ◽  
Vol 231 (1) ◽  
pp. 19-32
Author(s):  
Wenlin Wang ◽  
Dingsong Yu ◽  
Rui Xu
Keyword(s):  
High Speed ◽  
Influential Factors ◽  
Service Performance ◽  
Relief Valve ◽  
High Speed Rail ◽  
Hydraulic Damper ◽  
Damping Characteristics ◽  
Model And Simulation ◽  
Wide Range ◽  
Entrained Air

In this study, an improved physical parametric model with key in-service parameters was established and experimentally validated for a high-speed railway hydraulic damper. A subtle variable oil property model was built and coupled into the full model to address the dynamic flow losses and the relief-valve system dynamics. Experiments were conducted to evaluate the accuracy and robustness of the full damper model and simulation, which determined the damping characteristics over an extremely wide range of excitation speeds. Further simulations with in-service conditions and excitations were performed using the validated model, and the results revealed that improper key in-service parameters, such as improper rubber attachment stiffness, entrained air ratios and small mounting clearances, can greatly degrade the damping capability of a hydraulic damper. The obtained physical model includes all the influential factors that have an impact on the damping characteristics, so it will serve as a useful basic theory in the prediction of in-service performance, optimal specification and product design optimization of hydraulic dampers for modern high-speed rail vehicles.

Multi-Objective Optimization of a Two-Disk Rotor System

2014 ◽  
Vol 705 ◽  
pp. 79-82
Author(s):  
Jing Jing Huang ◽  
Long Xi Zheng ◽  
Mei Qing
Keyword(s):  
Design Optimization ◽  
High Speed ◽  
Maximum Amplitude ◽  
Optimization Method ◽  
Rotor System ◽  
Practical Significance ◽  
Flexible Rotor ◽  
Multi Objective ◽  
Aero Engine ◽  
Minimum Amplitude

A two-disk rotor system under the aero-engine support structure of typical 1-0-1 was established and the dynamical characteristics were analyzed. The two-disk rotor model was integrated to the Isight. The multi-objective design optimization of the transient process was then carried out with Evolutionary Optimization Algorithm. The optimum positions of the two-disk rotor system were obtained at the specified constraints. In order to verify the validity of the design optimization, the transient test was carried out on a high-speed flexible rotor mockup. The maximum amplitude of disk 1 cross the first critical rotation speed fell 50% and the maximum amplitude of disk 2 decreased by 20%. Experimental results indicated that the optimization method could obtain the position of the flexible rotor with the minimum amplitude and improve the design efficiency and quality, which had practical significance in the design of aero-engine rotor system.

Experimental research into the low-temperature characteristics of a hydraulic damper and the effect on the dynamics of the pantograph of a high-speed train running in extreme cold weather conditions

2019 ◽  
Vol 234 (8) ◽  
pp. 896-907
Author(s):  
Wenlin Wang ◽  
Yuwen Liang ◽  
Weihua Zhang ◽  
Simon Iwnicki
Keyword(s):  
Low Temperature ◽  
Experimental Research ◽  
High Speed ◽  
Weather Conditions ◽  
Cold Weather ◽  
Temperature Characteristics ◽  
Hydraulic Damper ◽  
Damping Characteristics ◽  
High Speed Trains ◽  
Extreme Cold

There is likely to be a demand to run high-speed trains in extreme cold weather conditions in the near future; therefore, it is important to study the change in the characteristics of the materials and components in an extreme cold environment and their effects on the vehicle system dynamics. Experimental research into the low temperature characteristics of a pantograph hydraulic damper was carried out in this study. The results show that low temperature causes an increase in damping forces, and when the temperature is above the boundary temperature range, most indices of the damping capability increase with the decrease of temperature; when the temperature is below the boundary temperature range, most indices decrease with the decrease of temperature. Key parameters are identified to obtain the theoretical description of low-temperature damping characteristics using a simplified-parametric damper model and the experimental data. A mathematical model of the pantograph–catenary system incorporating the pantograph damper model is then established to calculate the effect of the damper performance on the pantograph dynamics low temperatures. Simulation results show that the lowering performance of the pantograph deteriorates noticeably due to the unstable low-temperature damping characteristics, but the deterioration of the raising performance and contact quality of the pantograph due to the low-temperature characteristics of the damper are less obvious. The results obtained in this study are valuable for understanding the low-temperature characteristics of a hydraulic damper, and instructive in the optimal specification of the pantograph damper for high-speed trains running in cold weather conditions.

Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

2013 ◽  
Author(s):  
J. Schiffmann
Keyword(s):  
Design Optimization ◽  
High Efficiency ◽  
Integrated Design ◽  
Heat Pumps ◽  
Small Scale ◽  
Multi Objective Optimization ◽  
Design Constraints ◽  
Multi Objective ◽  
Wide Range ◽  
Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

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