scholarly journals Assessment of Dynamic Properties of Variable Area Flowmeters

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2917
Author(s):  
Mateusz Turkowski ◽  
Artur Szczecki ◽  
Maciej Szudarek ◽  
Krzysztof Janiszowski
Keyword(s):  
Natural Frequency ◽  
Dynamic Properties ◽  
Ease Of Use ◽  
Step Response ◽  
Design Stage ◽  
Response Type ◽  
Damping Coefficients ◽  
Non Linear Equation ◽  
Linearized Model ◽  
Sufficient Precision

In previous works, a non-linear equation describing variable area (VA) flowmeters in transient was presented. The use of a full nonlinear equation, despite giving accurate results, can be difficult and time-consuming and it requires having specific software and knowledge at one’s disposal. The goal of this paper was to simplify the existing model so that it could be used in applications where ease of use and ease of implementation are more important than accuracy. The existing model was linearized and simple formulae describing natural frequency and damping coefficients were derived. With these parameters, it is possible to assess the dynamic properties of a variable area flowmeter. The step response form can be identified and natural frequency and settling time can be estimated. The linearized model and the experiment were in reasonable agreement. The step response type was captured correctly for each of the six VA meter types. The error in the undamped natural frequency was not larger than 15%, which means that the VA meter sensor’s dynamic properties can be predicted at the design stage with sufficient precision.

Measured natural periods of concrete shear wall buildings: insights for the design of Canadian buildings

2012 ◽  
Vol 39 (8) ◽  
pp. 867-877 ◽  
Author(s):  
Damien Gilles ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Dynamic Properties ◽  
Response Spectrum ◽  
Shear Wall ◽  
Mode Shapes ◽  
Design Stage ◽  
Base Shear ◽  
Period Equation ◽  
Input Load ◽  
Structural Engineers

Structural engineers routinely use rational dynamic analysis methods for the seismic analysis of buildings. In linear analysis based on modal superposition or response spectrum approaches, the overall response of a structure (for instance, base shear or inter-storey drift) is obtained by combining the responses in several vibration modes. These modal responses depend on the input load, but also on the dynamic characteristics of the building, such as its natural periods, mode shapes, and damping. At the design stage, engineers can only predict the natural periods using eigenvalue analysis of structural models or empirical equations provided in building codes. However, once a building is constructed, it is possible to measure more precisely its dynamic properties using a variety of in situ dynamic tests. In this paper, we use ambient motions recorded in 27 reinforced concrete shear wall (RCSW) buildings in Montréal to examine how various empirical models to predict the natural periods of RCSW buildings compare to the periods measured in actual buildings under ambient loading conditions. We show that a model in which the fundamental period of RCSW buildings varies linearly with building height would be a significant improvement over the period equation proposed in the 2010 National Building Code of Canada. Models to predict the natural periods of the first two torsion modes and second sway modes are also presented, along with their uncertainty.

Іmprovement of driving-speed properties improvement of the method for selecting the parameters of the motor-transmission unit car

2021 ◽  
Vol 13 (1) ◽  
pp. 111-117
Author(s):  
Mikhail Podrigalo ◽  
◽  
Volodymyr Krasnokutskyi ◽  
Vitaliy Kashkanov ◽  
Olexander Tkachenko ◽  
...  
Keyword(s):  
Aerodynamic Drag ◽  
Dynamic Properties ◽  
Aerodynamic Characteristics ◽  
Gear Ratio ◽  
Design Stage ◽  
Transmission Unit ◽  
Air Resistance ◽  
Design Speed ◽  
Maximum Design ◽  
Engine Power

Aerodynamic characteristics have a major impact on the energy efficiency and traction and speed properties of the vehicle. In this article, based on previous studies of the aerodynamic characteristics of various car models, we propose an improved method for selecting engine and transmission parameters at the design stage. The aim of the study is to improve the dynamic properties of the car by improving the method of selecting the main parameters of the engine-transmission unit by refining the calculation of aerodynamic drag. To achieve it, the following tasks must be solved: to specify the method of selecting the maximum effective engine power; to specify a technique of definition of the maximum constructive speed of the car; to develop a technique for selecting gear ratios. The aerodynamic resistance to the movement of the vehicle is determined by the frontal coefficient of the specified resistance, the density of the air, the area of the frontal resistance and the speed of the vehicle. It is known from classical works on the aerodynamics of a car that in the range of vehicle speeds from 20 m / s to 80 m / s, taking the law of squares when assessing the force of air resistance, it is necessary to change the coefficient of frontal aerodynamic drag depending on the speed of the car. However, when carrying out calculations, this coefficient is taken constant, which leads to obtaining large values of the air resistance force at high speeds and lower at low speeds. There are two possible ways to improve the dynamic properties and energy efficiency of the car during its modernization (increasing the maximum design speed of the car by reducing the gear ratio in higher gear; reducing the maximum efficiency of the engine while maintaining the previous gear ratio in higher gear). As a result of the study, the method of selection (maximum effective engine power; maximum design speed of the car; gear ratios) at the design stage of the parameters of the motor-transmission unit of the car has been improved.

Dynamic Property Evaluation of a Long-Span Cable-Stayed Bridge (Sutong Bridge) by a Bayesian Method

2018 ◽  
Vol 19 (01) ◽  
pp. 1940010 ◽  
Author(s):  
Yan-Chun Ni ◽  
Qi-Wei Zhang ◽  
Jian-Feng Liu
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Structural Damage ◽  
Dynamic Properties ◽  
Modal Identification ◽  
Modal Parameters ◽  
Modal Parameter ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Sutong Bridge

Modal identification aims at identifying the dynamic properties including natural frequency, damping ratio, and mode shape, which is an important step in further structural damage detection, finite element model updating, and condition assessment. This paper presents the work on the investigation of the dynamic characteristics of a long-span cable-stayed bridge-Sutong Bridge by a Bayesian modal identification method. Sutong Bridge is the second longest cable-stayed bridge in the world, situated on the Yangtze River in Jiangsu Province, China, with a total length of 2 088[Formula: see text]m. A short-term nondestructive on-site vibration test was conducted to collect the structural response and determine the actual dynamic characteristics of the bridge before it was opened to traffic. Due to the limited number of sensors, multiple setups were designed to complete the whole measurement. Based on the data collected in the field tests, modal parameters were identified by a fast Bayesian FFT method. The first three modes in both vertical and transverse directions were identified and studied. In order to obtain modal parameter variation with temperature and vibration levels, long-term tests have also been performed in different seasons. The variation of natural frequency and damping ratios with temperature and vibration level were investigated. The future distribution of the modal parameters was also predicted using these data.

scholarly journals Designing a ship course controller by applying the adaptive backstepping method

2012 ◽  
Vol 22 (4) ◽  
pp. 985-997 ◽  
Author(s):  
Anna Witkowska ◽  
Roman Śmierzchalski
Keyword(s):  
Time Domain ◽  
System Performance ◽  
Control Algorithm ◽  
Control Structure ◽  
Dynamic Properties ◽  
Time Domain Analysis ◽  
Design Stage ◽  
Backstepping Method ◽  
Adaptive Backstepping ◽  
Nonlinear Static

The article discusses the problem of designing a proper and efficient adaptive course-keeping control system for a seagoing ship based on the adaptive backstepping method. The proposed controller in the design stage takes into account the dynamic properties of the steering gear and the full nonlinear static maneuvering characteristic. The adjustable parameters of the achieved nonlinear control structure were tuned up by using the genetic algorithm in order to optimize the system performance. A realistic full-scale simulation model of the B-481 type vessel including wave and wind effects was applied to simulate the control algorithm by using time domain analysis.

Springing Responses Analysis and Segmented Model Testing on a 550,000 DWT Ore Carrier

2016 ◽  
Author(s):  
Hui Li ◽  
Di Wang ◽  
Cheng Ming Zhou ◽  
Kaihong Zhang ◽  
Huilong Ren
Keyword(s):  
Natural Frequency ◽  
Design Stage ◽  
Resonant Vibration ◽  
Bending Moments ◽  
Wave Loads ◽  
Regular Waves ◽  
Segmented Model ◽  
Ship Model ◽  
Hull Structure ◽  
Stiffness Distribution

For ultra large ore carriers, springing response should be analyzed in the design stage since springing is the steady-state resonant vibration and has an important effect on the fatigue strength of hull structure. The springing response of a 550,000 DWT ultra large ore carrier has been studied by using experimental and numerical methods. A flexible ship model composed of nine segments was used in the experiment. The model segments were connected by a backbone with varying section, which can satisfy the request of natural frequency and stiffness distribution. The experiments in regular waves were performed and the motions and wave loads of the ship were measured. The experimental results showed that springing could be excited when the wave encounter frequency coincides with half or one-third the flexural natural frequency of the ship. In this paper, the analysis of the hydroelastic responses of the ultra large ore carrier was also carried out using a 3-D hydroelastic method. Comparisons between experimental and numerical results showed that the 3-D hydroelastic method could predict the motions and the vertical bending moments quite well. Based on this numerical method, the fatigue damage was estimated and the contribution of springing was analyzed.

scholarly journals Approach to Stochastic Modeling of Power Systems

2010 ◽  
Vol 26 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Alexander Rubtsov
Keyword(s):  
Power Systems ◽  
Power System ◽  
Stochastic Modeling ◽  
Transfer Functions ◽  
Dynamic Properties ◽  
Stochastic Disturbance ◽  
Modeling Power ◽  
Linearized Model ◽  
System Power ◽  
Made In

Approach to Stochastic Modeling of Power SystemsThis paper presents an approach to modeling power system that contains sources of stochastic disturbance. It is based on frequency analysis of linearized model of power system. Power system dynamic properties are accounted by equivalent transfer functions of machines and their control equipment. This will allow more accurate calculations for different analysis tasks. Methodology of system linearization is proposed and results of linearized model test are delivered.The research was made in frame of a project with funding participation of the European Commission.

Leveraging Flow Regeneration in Individual Energy-Efficient Hydraulic Drives

2021 ◽  
Author(s):  
Damiano Padovani
Keyword(s):  
Natural Frequency ◽  
Dynamic Properties ◽  
Poor Performance ◽  
Control Techniques ◽  
Lower Natural Frequency ◽  
Operating Region ◽  
Depth Analysis ◽  
Study Case ◽  
Boom Crane ◽  
Circuit Configuration

Abstract The current demand for energy efficiency in hydraulics directs towards the replacement of centralized, valve-controlled actuators with individual, throttleless drives. The resulting solutions often require an undesirable sizing of the key components to expand the system’s operating region. Using flow regeneration (i.e., shortcutting the actuator’s chambers) mitigates this issue. Such an option, already stated for individual drives, lacks an in-depth analysis from the control perspective since the dynamic properties are changed (e.g., the natural frequency is decreased to about 60% of the original value). Therefore, this research paper studies a representative single-pump architecture arranged in a closed-circuit configuration. Linear control techniques are used to understand the system dynamics and design a PI-control algorithm that also adds active damping. The outcomes are validated via high-fidelity simulations referring to a single-boom crane as the study case. The results encompassing diverse scenarios indicate that flow regeneration is only interesting in those applications where the dynamic response is not demanding. In fact, the lower natural frequency reduces the system’s bandwidth to about 69% of the original value and affects the closed-loop position tracking drastically. This poor performance becomes evident when medium-to-high actuation velocity is commanded with respect to the maximum value.

Studies of Magnetically Active Silicone Elastomers on a Vibrostend

2021 ◽  
Vol 1037 ◽  
pp. 141-147
Author(s):  
Andrey Minaev ◽  
Juri Korovkin ◽  
Hammat Valiev ◽  
G.V. Stepanov ◽  
Dmitry Yu. Borin
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Dynamic Properties ◽  
Experimental Studies ◽  
Magnetic Field Effect ◽  
Magnetorheological Elastomer ◽  
Silicone Elastomers ◽  
Damping Coefficients ◽  
Deformation Properties ◽  
The Magnetic Field

Experimental studies magnetorheological elastomer specimens dynamic properties under the magnetic fields action on the vibrostend are carried out. Amplitude-frequency characteristics have been obtained. The magnetic field effect on the silicone magnetoreactive elastomers deformation properties and damping coefficients experimentally is established.

Natural Frequency Region – Fluid-Structural-Interaction approach for dynamic impact predictions and experimental verification of rubber–metal bonded systems with fluid

2018 ◽  
Vol 233 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Robert K Luo ◽  
Ping Lou ◽  
Weidong Wang ◽  
Naizheng Guo
Keyword(s):  
Natural Frequency ◽  
Experimental Verification ◽  
Time Frame ◽  
Frequency Region ◽  
Design Stage ◽  
Dynamic Impact ◽  
Structural Interaction ◽  
Central Processing ◽  
Interaction Approach ◽  
Impact Predictions

This paper presents an integrated procedure for dynamic impact predictions and an experimental verification of rubber–metal bonded components with fluid to be used as a potential application in rail vehicle suspensions. There are three steps involved in the procedure. First, a quasi-static analysis was performed to verify the elastic properties of the rubber material using hyperelastic models. Second, a dynamic impact evaluation on selected hydro-mounts without fluid was conducted using the Natural Frequency Region (NFR) approach. Finally, a coupled NFR (with Fluid-Structural-Interaction) approach, different from the usual viscoelastic methods, was initiated to predict the dynamic impact responses of these components with the fluid in time domain. All the analyses have been validated with experimental data. The first two stages have been briefly described and the third stage is detailed in this paper. It should be noted that a powerful computer with multi-central processing units is essential to obtain a reasonable result within an acceptable time frame. It took approximately 40 h wall-clock time to complete the analysis using a workstation with 10 central processing units. It has been suggested that the natural frequency region–fluid–structure interaction methodology is reliable and could be used at the design stage and for engineering applications.

Natural-frequency concept utilized in remote probing of the earth

2003 ◽  
Vol 81 (4) ◽  
pp. 705-712 ◽  
Author(s):  
S T Bishay ◽  
O M Abo-Seida ◽  
G M Sami
Keyword(s):  
Natural Frequency ◽  
Analytical Form ◽  
Step Response ◽  
Earth Model ◽  
Induced Voltage ◽  
Diagnostic Features ◽  
Vertical Magnetic Dipole ◽  
Remote Probing ◽  
Displacement Currents ◽  
Layered Ground

The complete time-domain fields due to a vertical magnetic dipole on the surface of a two-layered earth model are derived in an analytical form using the natural-frequency concept. In these expressions, the displacement currents in the earth's layers are taken into consideration. The step responses of the induced voltage in a horizontal receiving loop is found to have definite diagnostic features for the ground beneath. These features are demonstrated by numerical results and shown by figures. The clear distinction between the step response of the homogeneous and the two-layered ground suggests that this response can be used for the detection of the stratification. PACS Nos.: 41.20.Jb, 42.25.Bs, 42.25.Gy, 44.05.+e

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