scholarly journals Research on dynamic response of subsea control system based on partial correlation analysis

2021 ◽  
Vol 39 (4) ◽  
pp. 847-857
Author(s):  
Peng Jia ◽  
Zhehua Zhang ◽  
Xiangyu Wang ◽  
Yongzhe Qu ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Hydraulic System ◽  
Partial Correlation ◽  
Circuit Simulation ◽  
Simulation Models ◽  
System Response ◽  
Single Factor ◽  
Response Curves ◽  
Factors Affecting ◽  
Object A ◽  
Control Response

In this article, taking a specific underwater hydraulic system as the research object, a closed loop circuit and a closed non-loop circuit simulation models are established; and through a single factor analysis, the interior factors such as different pipeline damping settings, underwater accumulators and actuators, and external factors such as water depth and return distance are analyzed. System response curves of these factors are obtained. Based on the single-factor simulation data, the partial correlation theory is used to analyze the correlation of the influencing factors of the control response for the underwater hydraulic system, and the order of the main factors affecting the control response of the underwater hydraulic system is obtained, which provides a reference for improving the response of the underwater hydraulic system.

scholarly journals Factors Affecting the Compression and Energy Absorption Properties of Small-Sized Thin-Walled Metal Tubes

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiaoqin Hao ◽  
Jia Yu ◽  
Weidong He ◽  
Yi Jiang
Keyword(s):  
Energy Absorption ◽  
Simulation Models ◽  
Simulation Method ◽  
Engineering Practice ◽  
Small Ring ◽  
Metal Tube ◽  
Absorption Properties ◽  
Factors Affecting ◽  
Thin Walled ◽  
Hollow Metal

To solve the problem of the effective cushioning of fast-moving mechanical components in small ring-shaped spaces, the factors affecting the compression and energy absorption properties of small-sized hollow metal tubes were studied. Simulation models were constructed to analyse the influences of tube diameter, wall thickness, relative position, and number of stacked components on the compression and energy absorption properties. The correctness of the simulation method and its output were verified by experiments, which proved the effectiveness of compression and energy absorption properties of small-sized thin-walled metal tubes. The research provides support for the application of metal tube buffers in armament launch technology and engineering practice.

Second Order Averaging Study of an Autoparametric System

1993 ◽  
Author(s):  
Bappaditya Banerjee ◽  
Anil K. Bajaj ◽  
Patricia Davies
Keyword(s):  
Dynamical Behavior ◽  
Period Doubling ◽  
Nonlinear Effects ◽  
Single Mode ◽  
Pitchfork Bifurcation ◽  
Second Order ◽  
System Response ◽  
Response Curves ◽  
Vibratory System ◽  
First Order

Abstract The autoparametric vibratory system consisting of a primary spring-mass-dashpot system coupled with a damped simple pendulum serves as an useful example of two degree-of-freedom nonlinear systems that exhibit complex dynamic behavior. It exhibits 1:2 internal resonance and amplitude modulated chaos under harmonic forcing conditions. First-order averaging studies of this system using AUTO and KAOS have yielded useful information about the amplitude dynamics of this system. Response curves of the system indicate saturation and the pitchfork bifurcation sets are found to be symmetric. The period-doubling route to chaotic solutions is observed. However questions about the range of the small parameter ε (a function of the forcing amplitude) for which the solutions are valid cannot be answered by a first-order study. Some observed dynamical behavior, like saturation, may not persist when higher-order nonlinear effects are taken into account. Second-order averaging of the system, using Mathematica (Maeder, 1991; Wolfram, 1991) is undertaken to address these questions. Loss of saturation is observed in the steady-state amplitude responses. The breaking of symmetry in the various bifurcation sets becomes apparent as a consequence of ε appearing in the averaged equations. The dynamics of the system is found to be very sensitive to damping, with extremely complicated behavior arising for low values of damping. For large ε second-order averaging predicts additional Pitchfork and Hopf bifurcation points in the single-mode response.

scholarly journals Imitation models of aircraft hydraulic units with account for typical faults

2019 ◽  
Vol 18 (1) ◽  
pp. 30-41
Author(s):  
A. M. Gareyev ◽  
I. A. Popelnyuk ◽  
D. M. Stadnik
Keyword(s):  
Hydraulic System ◽  
Quantitative Estimation ◽  
Simulation Models ◽  
Statistical Information ◽  
Hydraulic Systems ◽  
Operational Parameters ◽  
Accurate Localization ◽  
Literary Sources ◽  
Reference Curves ◽  
The Impact

А method based on comparing oscilloscope patterns of operational parameters with reference curves is one of the most promising methods of diagnosing hydraulic systems among the existing ones. Its implementation does not allow accurate localization of the faulty unit in the system and quantitative estimation of the magnitude of the fault. To eliminate these shortcomings, it is advisable to use simulation models of hydraulic units, taking into account typical faults of a hydraulic system. Their use makes it possible to evaluate the effect of a particular malfunction on the change of dynamic parameters at the stage of mathematical modeling. As a result of the analysis of statistical information and literary sources, characteristic faults of hydraulic systems are identified. Their causes and the impact on the operation of hydraulic units are examined. Simulation models of units taking into account typical faults are described in the Matlab / Simscape software package. They are implemented using a typical hydraulic system as an example. Dynamic characteristics of a hydraulic system in a healthy condition and those of a system with one of the characteristic faults are compared.

scholarly journals Modeling and analysis of the characteristics of SiC MOSFET

2021 ◽  
Vol 2125 (1) ◽  
pp. 012051
Author(s):  
Guoqing Qiu ◽  
Kedi Jiang ◽  
Shengyou Xu ◽  
Xin Yang ◽  
Wei Wang
Keyword(s):  
Simulation Model ◽  
Circuit Simulation ◽  
Power Conversion ◽  
Simulation Models ◽  
Data Sheet ◽  
Superior Performance ◽  
Power Devices ◽  
Matlab Simulink ◽  
Modeling And Analysis ◽  
Mathematical Processing

Abstract Although the superior performance of SiC MOSFET devices has beenvalidated by many studies, it is necessary to overcome many technical bottlenecks to make SiC MOSFET gradually replace Si-based power devices into the mainstream. In view of the current situation where the performance of SiC MOSFETs in power conversion devices cannot be evaluated well at this stage, it is necessary to carry out fine modeling of SiC MOSFETs and establish accurate simulation models. In this paper, the powerful mathematical processing capability and rich modules of Matlab/Simulink are used to build a SiC MOSFET model, and then the product data sheet is compared with the fitted data. The results show that the switching simulation waveforms are in general agreement with the data sheet waveforms, and the error is less than 7%. Verifing the accuracy of the model and reducing the difficulty of modeling, it provides a new idea for establishing the circuit simulation model of SiC MOSFET in Matlab/Simulink.

scholarly journals Characteristic Analysis of longitudinal vibration Sucker Rod String With Variable Equivalent Stiffness

2018 ◽  
Vol 153 ◽  
pp. 06009 ◽  
Author(s):  
Jian Lv ◽  
Mingming Xing
Keyword(s):  
Longitudinal Vibration ◽  
Step Function ◽  
Load Force ◽  
System Response ◽  
Equivalent Stiffness ◽  
Function Form ◽  
Characteristic Analysis ◽  
Response Curves ◽  
Sucker Rod ◽  
Force Excitation

Considering the influence of variable equivalent stiffness on system response, the equivalent stiffness is defined as a step function, and a mathematical model of nonlinear longitudinal vibration of sucker rod string (SRS) is built. The dynamic response under displacement and load force excitation is solved by fourth-order Runge-Kutta method with zero initial condition. The results show the steady-state responses under the displacement and load force excitation of different function forms are different. The response curves of both displacement and velocity under the displacement and load force excitation of cosine function form have larger fluctuation than it under the displacement and load force excitation of sine function form. Therefore, the characteristic analysis of SRS plays an important role in understanding the influence of the excitation form and sensitive parameters on steady response.

Experimental study on the repeatability of positioning of linear axes of machine tools

2019 ◽  
Vol 234 (4) ◽  
pp. 739-751
Author(s):  
Guangming Sun ◽  
Gaiyun He ◽  
Dawei Zhang ◽  
Bohui Ding
Keyword(s):  
Experimental Study ◽  
Machine Tools ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Experimental Investigations ◽  
Single Factor ◽  
Factors Affecting ◽  
Assembly Method ◽  
Orthogonal Experiments ◽  
Control Machine

This study presents experimental investigations on the mechanisms of the repeatability of positioning of linear axes of computer numerical control machine tools. First, the factors affecting the repeatability of positioning of linear axes are obtained based on orthogonal experiments. Second, the mechanism of each factor affecting the repeatability of positioning is studied based on single-factor experiments. Finally, an assembly method to improve the repeatability of positioning of linear axes is proposed. The method can provide designers and workers with informative guidelines for improving the repeatability of positioning in design and assembly processes.

Analysis of Free Nonlinear Vibration Behavior for Curved Embedded Carbon Nanotubes on Elastic Foundation

2010 ◽  
Author(s):  
M. Rezaee ◽  
H. Fekrmandi
Keyword(s):  
Carbon Nanotubes ◽  
Dynamic Behavior ◽  
Continuum Mechanics ◽  
Nonlinear Term ◽  
Nonlinear Oscillations ◽  
Equation Of Motion ◽  
System Response ◽  
Response Curves ◽  
Vibration Behavior ◽  
The Continuum

Carbon nanotubes (CNTs) are expected to have significant impact on several emerging nanoelectromechanical (NEMS) applications. Vigorous understanding of the dynamic behavior of CNTs is essential for designing novel nanodevices. Recent literature show an increased utilization of models based on elastic continuum mechanics theories for studying the vibration behavior of CNTs. The importance of the continuum models stems from two points; (i) continuum simulations consume much less computational effort than the molecular dynamics simulations, and (ii) predicting nanostructures behavior through continuum simulation is much cheaper than studying their behavior through experimental verification. In numerous recent papers, CNTs were assumed to behave as perfectly straight beams or straight cylindrical shells. However, images taken by transmission electron microscopes for CNTs show that these tiny structures are not usually straight, but rather have certain degree of curvature or waviness along the nanotubes length. The curved morphology is due to process-induced waviness during manufacturing processes, in addition to mechanical properties such as low bending stiffness and large aspect ratio. In this study the free nonlinear oscillations of wavy embedded multi-wall carbon nanotubes (MWCNTs) are investigated. The problem is formulated on the basis of the continuum mechanics theory and the waviness of the MWCNTs is modeled as a sinusoidal curve. The governing equation of motion is derived by using the Hamilton’s principle. The Galerkin approach was utilized to reduce the equation of motion to a second order nonlinear differential equation which involves a quadratic nonlinear term due to the curved geometry of the beam, and a cubic nonlinear term due to the stretching effect. The system response has been obtained using the incremental harmonic balanced method (IHBM). Using this method, the iterative relations describing the interaction between the amplitude and the frequency for the single-wall nanotube and double-wall nanotube are obtained. Also, the influence of the waviness, elastic medium and van der Waals forces on frequency-response curves is researched. Results present some useful information to analyze CNT’s nonlinear dynamic behavior.

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