scholarly journals Development and Parametric Analysis of Vibration System Controlled by Hydraulic Shock Rotary Vibrator

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Qichao Ren ◽  
Ziming Kou ◽  
Juan Wu ◽  
Tengyu Li ◽  
Waled Yahya
Keyword(s):  
Spindle Speed ◽  
Energy Utilization ◽  
Hydraulic Shock ◽  
Excitation System ◽  
Oil Supply ◽  
Supply Pressure ◽  
Vibration Excitation ◽  
Proposed Model ◽  
System Output ◽  
Excitation Force

The improvement of the energy utilization rate of a hydraulic vibration-excitation system is critical to the research and development of hydraulic vibration equipment. In this paper, a hydraulic vibration-excitation system controlled by a new type of shock rotary vibrator is proposed. A system model considering the pipeline effect was established for the hydraulic shock phenomenon. In addition, the model was compared with the one that does not consider the pipeline effect. The effectiveness of the proposed model was verified experimentally. Finally, the shock phenomenon during the process of switching the working state of the vibrator and the influence of certain important parameters of the system on the vibration output were investigated based on the proposed model. The results showed that (1) the hydraulic shock phenomenon occurred when the working state of the hydraulic vibrator was switched and (2) the hydraulic shock wave could effectively improve the excitation force of the system. The excitation force increased with an increase in the oil supply pressure, spindle speed, and load. However, it was negatively correlated with the spring stiffness. The amplitude of the vibration waveform output was positively correlated with the oil supply pressure and negatively correlated with the spindle speed and load. The amplitude first increased and then decreased as the stiffness of the vibration spring increased. The only influence of the precompressed length of the spring on the system output was its alteration of the vibration center of the system output vibration.

scholarly journals Machine Learning and Prediction-Based Resource Management in IoT Considering Qos

2019 ◽  
Vol 8 (2) ◽  
pp. 687-694
Keyword(s):  
Machine Learning ◽  
Prediction Model ◽  
Short Term Memory ◽  
Real Data ◽  
Computing Methods ◽  
Energy Utilization ◽  
Real Field ◽  
Proposed Model ◽  
Improved Performance ◽  
Video Sensors

Internet of Things (IoT) is one of the fast-growing technology paradigms used in every sectors, where in the Quality of Service (QoS) is a critical component in such systems and usage perspective with respect to ProSumers (producer and consumers). Most of the recent research works on QoS in IoT have used Machine Learning (ML) techniques as one of the computing methods for improved performance and solutions. The adoption of Machine Learning and its methodologies have become a common trend and need in every technologies and domain areas, such as open source frameworks, task specific algorithms and using AI and ML techniques. In this work we propose an ML based prediction model for resource optimization in the IoT environment for QoS provisioning. The proposed methodology is implemented by using a multi-layer neural network (MNN) for Long Short Term Memory (LSTM) learning in layered IoT environment. Here the model considers the resources like bandwidth and energy as QoS parameters and provides the required QoS by efficient utilization of the resources in the IoT environment. The performance of the proposed model is evaluated in a real field implementation by considering a civil construction project, where in the real data is collected by using video sensors and mobile devices as edge nodes. Performance of the prediction model is observed that there is an improved bandwidth and energy utilization in turn providing the required QoS in the IoT environment.

scholarly journals Vibration Frequency Characteristic Study of Two-stage Excitation Valve Used in Vibration Experiment System

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Yongping WU ◽  
Chengwei XIONG ◽  
Yi LIU ◽  
Jiafei ZHENG ◽  
Mingxuan ZOU
Keyword(s):  
High Frequency ◽  
Rotary Valve ◽  
Two Stage ◽  
Maximum Displacement ◽  
Experiment System ◽  
Oil Supply ◽  
Supply Pressure ◽  
Vibration Experiment ◽  
Working Principle ◽  
Large Flow

To satisfy the demands of higher frequency and amplitude in hydraulic vibration experiment system, the two-stage excitation valve is presented, and a mathematical model of two-stage excitation valve is established after analyzing the working principle of two-stage excitation valve, then the influence of relevant parameters on the displacement of main spool of two-stage excitation valve is studied by using Matlab/Simulink to calculate and analyze. The results show that the displacement of main spool will be smaller with bigger diameter and more secondary valve ports. When the reversing frequency is higher and the oil supply pressure is lower as well as the axial guide width of valve ports is smaller, the maximum displacement of main spool is smaller. The new two-stage excitation valve is easy to adjust reversing frequency and flow. The high frequency can be achieved by improving the rotation speed of servo motor and adding the number of secondary valve ports; the large flow can be realized by increasing the axial guide width of secondary valve ports and oil supply pressure. The result of this study is of guiding significance for designing the rotary valve for the achievement of higher reversing frequency and larger flow.

scholarly journals Research on a Coupled Total-Flow and Single-Flash (TF-SF) System for Power and Freshwater Generation from Geothermal Source

2020 ◽  
Vol 10 (8) ◽  
pp. 2689 ◽  
Author(s):  
Guopeng Yu ◽  
Zhibin Yu
Keyword(s):  
Power Generation ◽  
Geothermal Energy ◽  
Energy Utilization ◽  
Condensation Process ◽  
Total Flow ◽  
Combined System ◽  
Geothermal Resources ◽  
Single Flash ◽  
System Output ◽  
Efficiency Effects

In response to the twin development challenges of energy shortage and water-scarcity in worldwide arid to semi-arid regions with geothermal resources, a new combined power and freshwater generation system is proposed for geothermal energy utilization. In this system, a total-flow turbine (TF) is employed to be coupled with the traditional single-flash (SF) system and thereafter the coupled TF-SF system is investigated in this work. In addition to power generation, the exhaust steam from turbines are recovered to produce freshwater through condensation. Based on the novel designed system, the production of both power and water are studied under variable wellhead conditions, including variable wellhead pressures, temperatures, mass flowrates, and vapor qualities. The temperature of the separating point at which the total-flow expansion ends and the steam expansion starts is studied for optimal system output. In addition, the efficiency effects of the total-flow turbine on performance of the combined system is also investigated. The power generation comparison shows good power potential of the proposed TF-SF combined system. An effective total-flow turbine with an average efficiency of 65% can lead to an optimal power capacity, exceeding the traditional single-flash (SF) system by 23.7%. Moreover, more than 1/3 of total wellhead discharge can be recovered as desalinated freshwater by the naturally equipped condensation process of the power plant, showing extra benefit from geothermal energy utilization.

The Effects of Oil Supply Pressure at different Groove Position on Temperature and Pressure Profile in Journal Bearing

2013 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
R. S. Dwyer-Joyce ◽  
Aidah Jumahat
Keyword(s):  
Journal Bearing ◽  
Pressure Profile ◽  
Diameter Ratio ◽  
Radial Load ◽  
Oil Supply ◽  
Supply Pressure ◽  
Pressure Profiles ◽  
Hydrodynamic Journal Bearing ◽  
Temperature And Pressure ◽  
Length To Diameter Ratio

The effects of oil supply pressure on the temperature and pressure at different groove locations on a hydrodynamic journal bearing were investigated. A journal with a diameter of 100 mm and a ½ length-to-diameter ratio was used. The supply pressure was set to 0.2, 0.5, and 0.7 MPa at seven different groove locations, namely, -45°, -30°, -15°, 0°, +15°, +30°, and +45°. Temperature and pressure profiles were measured at speed values of 300, 500, and 800 rpm with 10 kN radial load. The results show that the change in oil supply pressure simultaneously reduced the temperature and increased the pressure profile.

Further Study of Quasiperiodic Vibration Excitation Forces in Rotated Triangular Tube Bundles Subjected to Two-Phase Cross Flow

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
C. Zhang ◽  
M. J. Pettigrew ◽  
N. W. Mureithi
Keyword(s):  
Flow Velocity ◽  
Cross Flow ◽  
Fretting Wear ◽  
Force Frequency ◽  
Two Phase ◽  
Vibration Excitation ◽  
Tube Bundles ◽  
Excitation Force ◽  
Lift Forces ◽  
Drag And Lift

Two-phase cross flow exists in many shell-and-tube heat exchangers. Flow-induced vibration excitation forces can cause tube motion that will result in long-term fretting-wear or fatigue. Detailed vibration excitation force measurements in tube bundles subjected to two-phase cross flow are required to understand the underlying vibration excitation mechanisms. Some of this work has already been done. Somewhat unexpected but significant quasiperiodic forces in both the drag and lift directions were measured. These forces are generally larger in the drag direction. However, the excitation force frequency is relatively low (i.e., 3–6 Hz) and not directly dependent on flow velocity in the drag direction. On the other hand, much higher frequencies (up to 16 Hz) were observed in the lift direction at the higher flow velocities. The frequency appears directly related to flow velocity in the lift direction. The present work aims at (1) providing further evidence of the quasiperiodic lift force mechanism, (2) determining the effect of cylinder position on such quasiperiodic drag and lift forces, and (3) verifying the existence of quasiperiodic drag and lift forces in a more realistic larger tube array. The program was carried out with two rotated triangular tube arrays of different width subjected to air/water flow to simulate two-phase mixtures from liquid to 95% void fraction. Both the dynamic lift and drag forces were measured with strain gauge instrumented cylinders.

The Effect of Oil Supply Pressure on the Circumferential Pressure Profile in Hydrodynamic Journal Bearing

2013 ◽  
Vol 315 ◽  
pp. 809-814 ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
Rob Dwyer-Joyce ◽  
Nik Rosli Abdullah
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Pressure Profile ◽  
Journal Bearings ◽  
Maximum Pressure ◽  
Oil Supply ◽  
Supply Pressure ◽  
Machine Elements ◽  
Hydrodynamic Journal Bearing ◽  
Circumferential Pressure

In hydrodynamic lubrication, the pressure condition of the fluid is critical to ensure good performance of the lubricated machine elements such as journal bearings. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on pressure profile around the circumference of a journal bearing. A journal diameter of 100mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 Mpa) and the circumferential pressure results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the maximum pressure values were affected by changes in oil supply pressure.

A Stochastic Model for Simulation and Diagnostics of Rolling Element Bearings With Localized Faults

2003 ◽  
Vol 125 (3) ◽  
pp. 282-289 ◽  
Author(s):  
J. Antoni ◽  
R. B. Randall
Keyword(s):  
Spectral Characteristics ◽  
Vibration Signal ◽  
Spectral Signature ◽  
Rolling Element Bearings ◽  
Envelope Analysis ◽  
Analysis Technique ◽  
Proposed Model ◽  
Rolling Element ◽  
Excitation Force ◽  
Localized Faults

This paper addresses the stochastic modeling of the vibration signal produced by localized faults in rolling element bearings and its use for diagnostic purposes. The aim is essentially to provide a better understanding of the recognized “envelope analysis” technique as classically used in the diagnostics of rolling element bearings, and incidentally give theoretical proofs for the specific features of envelope spectra as obtained from experimental data. The proposed model may also prove useful for simulation purposes. First, the excitation force generated by a defect is modeled as a random point process and its spectral signature is derived analytically. Then its transmission through the bearing is investigated in detail in order to find the spectral characteristics of the resulting vibration signal. The analysis finally gives sound justification for “squared” envelope analysis and the type of spectral indicators that should be used with it.

scholarly journals Performance and evaluation of location energy aware trusted distance source routing protocol for secure routing in WSNs

2020 ◽  
Vol 13 (39) ◽  
pp. 4092-4108
Author(s):  
M Rajasekaran
Keyword(s):  
Clustering Algorithm ◽  
Secure Routing ◽  
Energy Utilization ◽  
Sensor Nodes ◽  
Energy Aware ◽  
Trust Mechanism ◽  
Source Routing ◽  
Proposed Model ◽  
Performance And Evaluation

Objectives: To propose a suitable algorithm for improving the network lifetime of Wireless Sensor Networks (WSNs). Methods/Findings: We proposed a suitable Location and Energy Aware Trusted Distance Source Routing (LEATDSR) algorithm. Here, the energy consumption, location and the data quality are equalized by the Quality of Service (QoS) based routing algorithms. In addition to this algorithm, an existing clustering algorithm is also incorporates for grouping the sensor nodes based on the trust, location, energy and distance. In this LEATDSR is capable of deciding the evaluation metrics which express the QoS. Moreover, a new trust mechanism is also introduced in this model that incorporates multi-attributes of various sensor nodes in terms of communication, data, energy, and recommendation. This new trust mechanism relies on an enhanced sliding window time by considering the occurrences of attack frequency for facilitating the discovery of anomalous behaviours of attackers. The enhanced energy utilization is established within the sensor nodes for performing the active data transmission. The performance of the proposed model is evaluated by conducting various experiments in a simulation environment which creates by using NS2. From the experiments conducted in this work, the average packet transfer rate is increased drastically when compared to existing models available in the literature.

Oil Flow Through Journal Bearing

1973 ◽  
Vol 95 (4) ◽  
pp. 546-552 ◽  
Author(s):  
G. R. Kulkarni
Keyword(s):  
Significant Influence ◽  
Feed Rate ◽  
Journal Bearing ◽  
Great Influence ◽  
Operating Characteristics ◽  
Oil Supply ◽  
Supply Pressure ◽  
Attitude Angle ◽  
Oil Flow ◽  
Flow Through

Oil feed rate is an important parameter governing the operating characteristics of a journal bearing. In the present paper investigation is carried out to explore the effect of oil groove location and supply pressure on the oil feed rate to the bearing. These results are further used to get variation in Sommerfeld number and attitude angle for different oil groove locations and supply pressures. The results indicate that oil groove location has a great influence on oil feed rate to the bearing. It is also observed that oil supply arrangement does not have a significant influence on Sommerfeld number and attitude angle.

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