scholarly journals Measurement Method for Fluid Pressure Fluctuation in Fluid-Conveying Pipe Using PVDF Piezoelectric Film Sensor

2021 ◽  
Vol 11 (3) ◽  
pp. 1299
Author(s):  
Song Liu ◽  
Xianmei Wu ◽  
Yuanyuan Kong ◽  
Xiuqian Peng
Keyword(s):  
Flow Velocity ◽  
Pressure Fluctuation ◽  
Pipe Wall ◽  
Mechanical Vibration ◽  
Fluid Pressure ◽  
Circumferential Stress ◽  
Stress And Strain ◽  
Piezoelectric Film ◽  
Film Sensor ◽  
Internal Fluid

As a representative fluid-transporting system, fluid-conveying pipes play an essential role in many fields. For a fluid-conveying pipe system in operation, fluid pulsation in pipes contains much information about fluid flow parameters (flow velocity, fluid pressure, etc.). Therefore, the measurement of fluid pulsation is important for understanding the internal fluid flow. To use polyvinylidene fluoride (PVDF) piezoelectric film sensors to indirectly measure the pressure fluctuation of the internal fluid, we simulated a fluid-conveying pipe with PVDF piezoelectric film sensors attached to the outer pipe wall. The simulation results showed that the variation of voltage signal of PVDF, circumferential stress and strain of the pipe wall, and the pressure fluctuation of internal fluid were highly positively correlated, which proved that the PVDF piezoelectric film sensor can be applied to indirectly measure the pressure fluctuation of internal fluid. We also studied the influences of flow velocity pulsation and mechanical vibration caused by the pipeline pump during operation. It is found that the flow velocity pulsation had little influence on the measurements of the variation of circumferential stress and strain of the pipe wall and the internal fluid pressure fluctuation. When both ends of the pipe were fixed by hoops, mechanical vibration had little influence on the measurement of the variation of circumferential stress and strain of the pipe wall as well as the fluid pressure fluctuation. Finally, simulation results were verified by experiments.

scholarly journals A Flow Velocity Measurement Method Based on a PVDF Piezoelectric Sensor

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1657 ◽  
Author(s):  
Qi Li ◽  
Junhua Xing ◽  
Dajing Shang ◽  
Yilin Wang
Keyword(s):  
Flow Velocity ◽  
Polyvinylidene Fluoride ◽  
Flow Direction ◽  
Piezoelectric Sensor ◽  
Piezoelectric Film ◽  
Film Sensor ◽  
Motion State ◽  
Flow Velocity Measurement ◽  
The Relationship ◽  
Piezoelectric Characteristics

To measure the flow velocity of a fluid without affecting its motion state, a method was proposed based on a polyvinylidene fluoride (PVDF) piezoelectric film sensor. A self-made PVDF piezoelectric sensor placed parallel with the flow direction was used to measure the flow velocity. First, the piezoelectric characteristics of PVDF were obtained theoretically. Next, the relationship between flow velocity and sound pressure was verified numerically. Finally, the relationship between flow velocity and the electrical output of the PVDF piezoelectric film was obtained experimentally. In conclusion, the proposed method was shown to be reliable and effective.

Monitoring Mechanical Vibration Amplitude System Design Based on the PVDF Piezoelectric Film Sensor

2014 ◽  
Vol 556-562 ◽  
pp. 2110-2113 ◽  
Author(s):  
Jia Lin Zhu ◽  
Li Li
Keyword(s):  
Measurement System ◽  
Vibration Amplitude ◽  
Simple Structure ◽  
Mechanical Vibration ◽  
Test System ◽  
Vibration Monitoring ◽  
Piezoelectric Film ◽  
Film Sensor ◽  
Data Acquisition And Processing ◽  
Amplitude System

Vibration monitoring of machinery and equipment plays a very important role in judging the equipment maintenance and operational status. This paper discussed the mechanical vibration amplitude measurement system scheme based on PVDF piezoelectric sensors. The entire test system is mainly composed of PVDF piezoelectric film sensors, charge amplifiers, data acquisition and processing and display of valid values. It can display the amplitude of vibration signals in real time and alarm. The measurement system has the advantages of a simple structure and convenient operation.

In-Plane Parametric Vibrations of Curved Bellows Subjected to Oscillating Internal Fluid Pressure Excitation

2004 ◽  
Author(s):  
Masahiro Watanabe ◽  
Eiji Tachibana ◽  
Nobuyuki Kobayashi
Keyword(s):  
Stability Analysis ◽  
Natural Frequencies ◽  
Parametric Instability ◽  
Fluid Pressure ◽  
Parametric Vibrations ◽  
Internal Fluid ◽  
Mathieu’S Equation ◽  
Stability Maps ◽  
Plane Direction ◽  
Pressure Excitation

This paper deals with the theoretical stability analysis of in-plane parametric vibrations of a curved bellows subjected to periodic internal fluid pressure excitation. The curved bellows studied in this paper are fixed at both ends rigidly, and are excited by the periodic internal fluid pressure. In the theoretical stability analysis, the governing equation of the curved bellows subjected to periodic internal fluid pressure excitation is derived as a Mathieu’s equation by using finite element method (FEM). Natural frequencies of the curved bellows are examined and stability maps are presented for in-plane parametric instability. It is found that the natural frequencies of the curved bellows decrease with increasing the static internal fluid pressure and buckling occurs due to high internal fluid pressure. It is also found that two types of parametric vibrations, longitudinal and transverse vibrations, occur to the curved bellows in-plane direction due to the periodic internal fluid pressure excitation. Moreover, effects of axis curvature on the parametric instability regions are examined theoretically.

scholarly journals Tactile Perception for Teleoperated Robotic Exploration within Granular Media

2021 ◽  
Vol 10 (4) ◽  
pp. 1-27
Author(s):  
Shengxin Jia ◽  
Veronica J. Santos
Keyword(s):  
Granular Media ◽  
Fluid Pressure ◽  
Tactile Sensor ◽  
Tactile Perception ◽  
Test Accuracy ◽  
Contact State ◽  
Buried Objects ◽  
Media Type ◽  
Additional Information ◽  
Internal Fluid

The sense of touch is essential for locating buried objects when vision-based approaches are limited. We present an approach for tactile perception when sensorized robot fingertips are used to directly interact with granular media particles in teleoperated systems. We evaluate the effects of linear and nonlinear classifier model architectures and three tactile sensor modalities (vibration, internal fluid pressure, fingerpad deformation) on the accuracy of estimates of fingertip contact state. We propose an architecture called the Sparse-Fusion Recurrent Neural Network (SF-RNN) in which sparse features are autonomously extracted prior to fusing multimodal tactile data in a fully connected RNN input layer. The multimodal SF-RNN model achieved 98.7% test accuracy and was robust to modest variations in granular media type and particle size, fingertip orientation, fingertip speed, and object location. Fingerpad deformation was the most informative modality for haptic exploration within granular media while vibration and internal fluid pressure provided additional information with appropriate signal processing. We introduce a real-time visualization of tactile percepts for remote exploration by constructing a belief map that combines probabilistic contact state estimates and fingertip location. The belief map visualizes the probability of an object being buried in the search region and could be used for planning.

Research on pressure fluctuation phenomenon using the smart isolation tool in subsea pipeline maintenance operation

2018 ◽  
Vol 233 (2) ◽  
pp. 643-652 ◽  
Author(s):  
Kang Zhang ◽  
Qingxin Ding ◽  
Shuhai Liu ◽  
Shimin Zhang ◽  
Xiaoxiao Zhu
Keyword(s):  
Aspect Ratio ◽  
Flow Velocity ◽  
Pressure Fluctuation ◽  
Subsea Pipeline ◽  
Control Precision ◽  
Time Flow ◽  
Fluctuation Phenomenon ◽  
Accurate Position ◽  
Peak Value ◽  
Deceleration Time

A new isolation technology in subsea pipeline maintenance has been gradually developed in recent years. During the operation, the smart isolation tool is desired to decelerate and stop in the accurate position, which will cause a pressure surge in pipe, it was named “pressure fluctuation phenomenon” in this article. For control precision and sealing reliability, avoiding or reducing the fluctuation phenomenon has been necessary. The characteristics of this phenomenon and the effects of parameters have been investigated using numerical methodologies. The results indicated that this phenomenon mainly affected by deceleration time, flow velocity and aspect ratio, and the optimal parameters are t = 1.5 s, v = 1 m/s and γ = 1.2, respectively. The identical results could be achieved from the sensitivity analysis. It can be concluded that the peak value is more sensitive to deceleration time, less sensitive to flow velocity and least sensitive to aspect ratio. All the studies in this article will provide a reference to improve the control precision and seal reliability using smart isolation tool in subsea pipeline maintenance.

Cerebral blood flow velocity and cerebrospinal fluid pressure after single bolus of propofol

1989 ◽  
Vol 11 (3) ◽  
pp. 150-151 ◽  
Author(s):  
A. Parma ◽  
R. Massei ◽  
A. Pesenti ◽  
C. Ferrari da Passano ◽  
G. Gran ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebrospinal Fluid ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Fluid Pressure ◽  
Cerebrospinal Fluid Pressure ◽  
Single Bolus

Buckling of Risers in Tension due to Internal Pressure: Nonmovable Boundaries

1983 ◽  
Vol 105 (3) ◽  
pp. 277-281 ◽  
Author(s):  
M. M. Bernitsas ◽  
T. Kokkinis
Keyword(s):  
Internal Pressure ◽  
Fluid Pressure ◽  
Critical Length ◽  
Entire Length ◽  
Tubular Columns ◽  
Internal Fluid ◽  
Static Instability

Open-ended tubular columns may buckle globally as Euler columns due to the action of internal fluid pressure even while they are in tension along their entire length. Hydraulic columns, marine drilling and production risers are, therefore, prone to such static instability. This paper explains this phenomenon, defines the critical riser length for which this instability may occur and provides graphs with values of the critical length which can readily be used for design purposes. Risers with nonmovable boundaries are considered; namely, hinged-hinged, clamped-hinged, hinged-clamped and clamped-clamped risers.

scholarly journals Analysis of Stress and Strain to Determine the Pressure Changes in Tight-Fitting Garment

2020 ◽  
Vol 20 (1) ◽  
pp. 49-55
Author(s):  
Nareerut Jariyapunya ◽  
Blažena Musilová
Keyword(s):  
Mechanical Properties ◽  
Mathematical Models ◽  
Initial Phase ◽  
Circumferential Stress ◽  
The Body ◽  
Stress And Strain ◽  
Laplace’S Law ◽  
Pressure Changes ◽  
The Relationship ◽  
Laplace's Law

AbstractBased on the mechanical properties of stretch fabrics and Laplace’s law, the mathematical models have been developed enabling one to determine the values of the relationship between the fabric strain and the circumferential stress depending on pressure and diameter of the body. The results obtained refer to the values of the parameters assessed for the initial phase of their exploitation, which allow us to preliminarily predict the values of these parameters.

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