Nonlinear Dynamic Model of a Two-Stage Pressure Relief Valve for Designers

2001 ◽  
Vol 124 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Pei-Sun Zung ◽  
Ming-Hwei Perng
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Dynamic Models ◽  
Operating Conditions ◽  
Model Parameters ◽  
Nonlinear Dynamic Model ◽  
Relief Valve ◽  
Two Stage ◽  
Pressure Relief ◽  
Wide Range

This paper presents a handy nonlinear dynamic model for the design of a two stage pilot pressure relief servo-valve. Previous surveys indicate that the performance of existing control valves has been limited by the lack of an accurate dynamic model. However, most of the existing dynamic models of pressure relief valves are developed for the selection of a suitable valve for a hydraulic system, and assume model parameters which are not directly controllable during the manufacturing process. As a result, such models are less useful for a manufacturer eager to improve the performance of a pressure valve. In contrast, model parameters in the present approach have been limited to dimensions measurable from the blue prints of the valve such that a specific design can be evaluated by simulation before actually manufacturing the valve. Moreover, the resultant model shows excellent agreement with experiments in a wide range of operating conditions.

scholarly journals A nonlinear dynamic model of magnetorheological elastomers in magnetic fields based on fractional viscoelasticity

2020 ◽  
pp. 1045389X2095361
Author(s):  
Guanghong Zhu ◽  
Yeping Xiong ◽  
Zigang Li ◽  
Ling Xiao ◽  
Ming Li ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Experimental Results ◽  
Model Parameters ◽  
Nonlinear Dynamic Model ◽  
Dynamic Moduli ◽  
Magnetorheological Elastomers ◽  
Proposed Model ◽  
Wide Range

As smart materials, magnetorheological elastomers (MREs) have been broadly applied in the field of intelligent structures and devices. In order to mathematically represent the dynamic behavior in a wide range of strain amplitude, excitation frequency and magnetic field; a nonlinear model with a fractional element was developed for MREs in a linear viscoelastic regime. The identification of model parameters was realized through fitting experimental data of dynamic moduli measured in shear mode, and the identified parameters exhibited good repeatability and consistency to reflect the rationality of this nonlinear dynamic model. Considering material elasticity and viscosity, the dependence of model parameters on strain amplitudes and magnetic fields was analyzed to interpret the dynamics of MREs. The fitted results displayed an excellent agreement with the experimental results on the dependence of dynamic moduli on strain amplitudes and magnetic fields. Using the predictor-corrector approach, predicted results on the stress-strain hysteresis loop were calculated based on identified parameters to further validate the proposed model by comparing with experimental results and predicted results of the revised Bouc-Wen model. This proposed model is expected to facilitate the dynamic analysis and simulation of MRE based vibration systems with a high precision accuracy.

Application of an Improved Streamline Curvature Approach to a Modern, Two-Stage Transonic Fan: Comparison With Data and CFD

2002 ◽  
Author(s):  
Keith M. Boyer ◽  
Walter F. O’Brien
Keyword(s):  
Three Dimensional ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Model Parameters ◽  
Two Stage ◽  
Streamline Curvature ◽  
Wide Range ◽  
Improved Model ◽  
Transonic Fan ◽  
Streamline Curvature Method

A streamline curvature method with improvements to key loss models is applied to a two-stage, low aspect ratio, transonic fan with design tip relative Mach number of approximately 1.65. Central to the improvements is the incorporation of a physics-based shock model. The attempt here is to capture the effects of key flow phenomena relative to the off-design performance of the fan. A quantitative analysis regarding solution sensitivities to model parameters that influence the key phenomena over a wide range of operating conditions is presented. Predictions are compared to performance determined from overall and interstage measurements, as well as from a three-dimensional, steady, Reynolds-averaged Navier-Stokes method applied across the first rotor. Overall and spanwise comparisons demonstrate that the improved model gives reasonable performance trending and generally accurate results. The method can be used to provide boundary conditions to higher-order solvers, or implemented within novel approaches using the streamline curvature method to explore complex engine-inlet integration issues, such as time-variant distortion.

Mathematical Modeling of a Two Spool Flow Control Servovalve Using a Pressure Control Pilot1

2002 ◽  
Vol 124 (3) ◽  
pp. 420-427 ◽  
Author(s):  
Randall T. Anderson ◽  
Perry Y. Li
Keyword(s):  
Mathematical Modeling ◽  
Flow Control ◽  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Pressure Control ◽  
Dynamic Effects ◽  
Nonlinear Dynamic Model ◽  
Two Stage ◽  
Matlab Simulink ◽  
Proposed Model

A nonlinear dynamic model for an unconventional, commercially available electrohydraulic flow control servovalve is presented. The two stage valve differs from the conventional servovalve design in that: it uses a pressure control pilot stage; the boost stage uses two spools, instead of a single spool, to meter flow into and out of the valve separately; and it does not require a feedback wire and ball. Consequently, the valve is significantly less expensive. The proposed model captures the nonlinear and dynamic effects. The model has been coded in Matlab/Simulink and experimentally validated.

Mathematical Modeling of a Two Spool Flow Control Servovalve Using a Pressure Control Pilot

2000 ◽  
Author(s):  
Randy T. Anderson ◽  
Perry Y. Li
Keyword(s):  
Mathematical Modeling ◽  
Flow Control ◽  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Pressure Control ◽  
Dynamic Effects ◽  
Nonlinear Dynamic Model ◽  
Two Stage ◽  
Proposed Model

Abstract A nonlinear dynamic model for an unconventional, commercially available electrohydraulic flow control servovalve is presented. The valve is a two-stage valve and differs from the conventional servovalve in that it does not require a feedback wire and ball, and the boost stage uses two spools, instead of a single spool, to meter flow into and out of the valve separately. Consequently, the valve is significantly less expensive. The proposed model captures the nonlinear and dynamic effects not present in previous models. The model has been coded in Simulink and experimentally validated.

Sliding behavior of high speed ball bearings based on improved nonlinear dynamic model

2021 ◽  
pp. 146441932110430
Author(s):  
Dongsheng Qian ◽  
Xiaotian Xu ◽  
Song Deng ◽  
Shaofeng Jiang ◽  
Lin Hua
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Dynamic Models ◽  
Time Varying ◽  
Ball Bearings ◽  
Nonlinear Dynamic Model ◽  
Dynamic Behaviors ◽  
Low Speeds ◽  
Heavy Loads

To accurately predict the dynamic behaviors of high speed ball bearings, an investigation on the sliding behavior of balls at high and low speeds, and light and heavy loads is necessary. However, existing nonlinear dynamic models fail to consider comprehensively key factors such as asperity and hydrodynamic tractions, time-varying friction coefficient and time-varying lubricant mode. In this work, these influencing factors are integrated into the nonlinear dynamic model to make it suitable for the working conditions of high and low speeds and light and heavy loads. The dynamic analysis provides the relation of angular speeds of balls with spin and sliding at light and heavy loads, also it reveals the number of pure rolling point under the combined effect of differential sliding and spin sliding. Research results provide a reliable mathematical model and theoretical bases for further studying the dynamic behaviors of high speed ball bearings.

scholarly journals Real-Time Disturbances Estimating and Compensating of Nonlinear Dynamic Model for Underwater Vehicles

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Yuexin Zhang ◽  
Lihui Wang
Keyword(s):  
Kalman Filter ◽  
Dynamic Model ◽  
Navigation System ◽  
Nonlinear Dynamic ◽  
Model Parameters ◽  
System State ◽  
Nonlinear Dynamic Model ◽  
External Disturbances ◽  
Cubature Kalman Filter ◽  
Nonlinear Disturbances

To reduce the deviation caused by the stochastic environmental disturbances, estimating these disturbances is required to compensate the navigation system. Based on the idea of Kalman filter using least-squares algorithm for optimal estimation, a nonlinear disturbances estimator which can be perfectly integrated with cubature Kalman filter (CKF) is proposed. For the nonlinear disturbances estimator, the disturbances are estimated by gain matrix, innovation sequences, and innovation covariance generated by CKF. The disturbances estimating and compensating algorithm consists of three parts. Firstly, the navigation system state space model is established based on nonlinear dynamic model of six degrees of freedom. Secondly, the external disturbances are estimated by using CKF and a nonlinear estimator. Finally, the disturbances compensation is carried out by improving the system state equation. In view of the uncertainty of the dynamic model and the randomness of external disturbances, numerical simulation experiments are conducted in the circumstances of sinusoidal disturbances, random disturbances, and uncertain model parameters. The results demonstrate that the proposed method can estimate disturbances effectively and improves navigation accuracy significantly.

Modelling and experimental verification of pressure relief synchronous control for small trapped fluid volumes

2018 ◽  
Vol 40 (9) ◽  
pp. 2960-2969 ◽  
Author(s):  
Gang Wang ◽  
Jianhua Wei ◽  
Jinhui Fang ◽  
Wenzhuo Shi ◽  
Qiang Zhang
Keyword(s):  
High Pressure ◽  
Experimental Verification ◽  
Control Method ◽  
Operating Conditions ◽  
Parameter Uncertainties ◽  
Relief Valve ◽  
Pressure Relief ◽  
Synchronous Control ◽  
Wide Range ◽  
Tracking Controller

This paper presents a pressure relief synchronous control method for four small entrapped high-pressure fluid volumes on a huge hydraulic machine. Firstly, as the existing pressure relief methods cannot behave well for small entrapped high-pressure fluid volumes, a novel electrohydraulic proportional pressure relief circuit is proposed. The electrohydraulic proportional pressure relief circuit is composed of a proportional pressure relief valve, a damping orifice and a constant pressure source, through which the pressure can be relieved proportionally to the command signal. Secondly, as the machine is a manned hydropower carrier, a very safety-critical application, a simple and easy to implement hybrid control scheme consisting of a synchronization controller and a pressure tracking controller is developed. As the pressure relief circuit has a wide range of operating conditions and parameter uncertainties, a practical self-tuning fuzzy proportion integration (PI) pressure tracking controller with feedforward is proposed, and a master–slave PI synchronization pressure controller with dead band is employed for the four entrapped fluid volumes. Finally, the experimental verification is implemented on a test stand to demonstrate the effectiveness of the proposed synchronous control system. The experimental results confirm that the pressure deviations among the four small entrapped high-pressure fluid volumes are bound within [Formula: see text].

scholarly journals Performance Evaluation of a Novel Hydro - Pneumatic Suspension System of a Heavy Truck on Ride Comfort

2021 ◽  
Vol 304 ◽  
pp. 01009
Author(s):  
Le Xuan Long ◽  
Dang Viet Ha ◽  
Le Van Quynh ◽  
Bui Van Cuong ◽  
Vu Thi Hien
Keyword(s):  
Nonlinear Dynamic ◽  
Dynamic Models ◽  
Ride Comfort ◽  
Suspension System ◽  
Operating Conditions ◽  
Road Surface ◽  
Nonlinear Dynamic Model ◽  
Study Results ◽  
Pneumatic Suspension ◽  
Heavy Truck

The purpose of this work is to evaluate the performance of novel hydrfo-pneumatic suspension system (HPSs) in comparison with traditional hydro-pneumatic fsuspension system (HPSs) of a heavy truck in the direction of improving vehicle ride comfort. Firstly, the nonlinear dynamic models of the traditional and novel HPS systems are set up to determine the vertical forces. And then, the vertical forces are connected with a 3-D nonlinear dynamic model of heavy truck with 10 degrees of freedom under random excitation of road surface. The root mean square (RMS) acceleration responses of the vertical cab, pitch and roll angles of the cab (awzcb, awfcb and awtcb) based on the International Standard ISO 2631-1: 1997 are chosen as objective functions. The study results show that the awzcb, awfcb and awtcb values with novel HPSs reduce by 28.27%, 28.32% and 6.89% in comparison with traditional HPSs when vehicle moves on ISO class D road surface at vehicle speed of 50 km/h and full load. Finally, the ride performance of novel HPSs is verified and compared and evaluated with traditional HPSs under different operating conditions and the evaluation results are also indicated that the ride performance of a novel HPSs is better than the traditional HPSs under survey conditions.

scholarly journals Dynamic Model for Axial Motion of Horizontal Pelton Turbine and Validation in Actual Failure Case

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
C. G. Rodriguez ◽  
D. Zambrano ◽  
S. Reyes ◽  
J. Tapia ◽  
M. Egusquiza ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Magnetic Force ◽  
Operating Conditions ◽  
Axial Position ◽  
Axial Motion ◽  
Nonlinear Dynamic Model ◽  
Pelton Turbine ◽  
Axial Forces ◽  
The Difference

Pelton turbines are important machines for power generation from a renewable energy source such as water. For power rates below 20 MW, the rotor of Pelton turbines is usually in horizontal position. Considering ideal mounting and operating conditions, there are no axial forces acting on the rotor. In practice, there is an hydraulic force due to the difference between nozzle centerline and bucket centerline, and there is a magnetic force due to the difference between axial position of stator and rotor magnetic field centers. These forces are supported by bearings. In this article, a nonlinear dynamic model considering these axial forces and bearings behavior is presented and solved for two different actual Pelton turbines. The nonlinear dynamic model allows determining and evaluating the source of axial motion and therefore provides valuable information in order to reduce it when the axial displacement is high enough to produce damage.

Optimal Web Guiding

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Aravind Seshadri ◽  
Prabhakar R. Pagilla
Keyword(s):  
Dynamic Model ◽  
Dynamic Models ◽  
Fiber Optic ◽  
Operating Conditions ◽  
Model Parameters ◽  
Linear Quadratic ◽  
Position Measurement ◽  
Series Of Experiments ◽  
Correct Application ◽  
Selection Of

This paper presents an optimal web guiding strategy based on the dynamic analysis of the lateral web behavior and a new fiber optic lateral web position measurement sensor. First, a lateral dynamic model of a moving web is revisited with an emphasis on correct application of appropriate boundary conditions. Then the dynamic models of two common intermediate guides (remotely pivoted guide and offset-pivot guide) are investigated. The effect of various model parameters on lateral web behavior is analyzed and discussions on proper selection of the parameters are given. Based on the model analysis, we discuss the design of a linear quadratic optimal controller that is capable of accommodating structured parametric uncertainties in the lateral dynamic model. The optimal guide control system is evaluated by a series of experiments on a web platform with different web materials under various operating conditions. Implementation of the controller with a new fiber optic lateral sensor for different scenarios is discussed. Results show good guiding performance in the presence of disturbances and with uncertainties in the model parameters.

Sign in / Sign up

Export Citation Format

Share Document