scholarly journals Parameters Analysis of Hydraulic-Electrical Energy Regenerative Absorber on Suspension Performance

2014 ◽  
Vol 6 ◽  
pp. 836502 ◽  
Author(s):  
Han Zhang ◽  
Xuexun Guo ◽  
Lin Xu ◽  
Sanbao Hu ◽  
Zhigang Fang
Keyword(s):  
Degrees Of Freedom ◽  
Influencing Factor ◽  
Check Valve ◽  
Electrical Energy ◽  
Hydraulic Motor ◽  
Orifice Area ◽  
Damping Characteristics ◽  
Sinusoidal Input ◽  
Force Velocity ◽  
Inner Diameter

To recycle the vibration energy of vehicles over rough roads, a hydraulic-electricity energy regenerative suspension (HEERS) was designed in the present work, and simulations were performed with focus on its performance. On the basis of the system principle, the mathematical model of hydraulic-electrical energy regenerative absorber (HEERA) and two degrees of freedom (DOF) suspension dynamic model were constructed. Using the model of HEERA, simulations on force-displacement and force-velocity characteristics were performed with a 1.67 Hz frequency and a sinusoidal input adopted. And then in combination with HEERA model and two DOF suspension models, simulations on the performance of HEERS also were carried out. Finally, the influences of charging pressure and volume of the accumulator, hydraulic motor displacement, orifice area of check valve, and inner diameter of hydraulic pipelines on the performance of HEERA and HEERS were investigated in depth. The simulation results indicated that (i) the damping characteristic of HEERA was coincident with the damping characteristics of traditional absorber; (ii) the most remarkable influencing factor on the performance of HEERS was the hydraulic motor displacement, followed by orifice area of check valve, inner diameter of pipelines, and charging pressure of accumulator, while the effects of charging volume of accumulator were quite limited.

scholarly journals Analysis of Damping Characteristics of a Hydraulic Shock Absorber

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhifei Wu ◽  
Guangzhao Xu ◽  
Hongwei Yang ◽  
Mingjie Li
Keyword(s):  
Shock Absorber ◽  
Check Valve ◽  
Line Length ◽  
Hydraulic Shock ◽  
Hydraulic Motor ◽  
Damping Force ◽  
Unidirectional Flow ◽  
Damping Characteristics ◽  
Hydraulic Shock Absorber ◽  
Inner Diameter

In the present study, a hydraulic shock absorber is proposed. Since the damper is mainly used in suspension energy recovery system, the damping characteristics of the damper under no-load state are studied in this paper. Structural design is conducted so that the unidirectional flow of the oil drives the hydraulic motor to generate electricity. Meanwhile, an asymmetrical extension/compression damping force is obtained. A mathematical model of the shock absorber is established, and the main characteristics of the inherent damping force are obtained. Based on the established model, effects of the accumulator volume, accumulator preinflation pressure, hydraulic motor displacement, check valve inner diameter, and spring stiffness, hydraulic line length and inner diameter on the indicator characteristics are analyzed. Moreover, a series of experiments are conducted on the designed damper to evaluate the characteristics of the inherent damping force and analyze the effect of the accumulator volume and preinflation pressure on the damping characteristics.

scholarly journals Real world assessment of an auto-parametric electromagnetic vibration energy harvester

2017 ◽  
Vol 29 (7) ◽  
pp. 1481-1499 ◽  
Author(s):  
Yu Jia ◽  
Jize Yan ◽  
Sijun Du ◽  
Tao Feng ◽  
Paul Fidler ◽  
...  
Keyword(s):  
Parametric Resonance ◽  
Real World ◽  
Average Power ◽  
Electrical Energy ◽  
Wireless Sensor ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Sinusoidal Input ◽  
Micro Electromechanical System

The convention within the field of vibration energy harvesting has revolved around designing resonators with natural frequencies that match single fixed frequency sinusoidal input. However, real world vibrations can be random, multi-frequency, broadband and time-varying in nature. Building upon previous work on auto-parametric resonance, this fundamentally different resonant approach can harness vibration from multiple axes and has the potential to achieve higher power density as well as wider frequency bandwidth. This article presents the power response of a packaged auto-parametric VEH prototype (practical operational volume of ∼126 cm−3) towards various real world vibration sources including vibration of a bridge, a compressor motor as well as an automobile. At auto-parametric resonance (driven at 23.5 Hz and 1 g rms), the prototype can output a peak of 78.9 mW and 4.5 Hz of −3dB bandwidth. Furthermore, up to ∼1 mW of average power output was observed from the harvester on the Forth Road Bridge. The harvested electrical energy from various real world sources were used to power up a power conditioning circuit, a wireless sensor mote, a micro-electromechanical system accelerometer and other low-power sensors. This demonstrates the concept of self-sustaining vibration powered wireless sensor systems in real world scenarios, to potentially realise maintenance-free autonomous structural health and condition monitoring.

The Influence of Passive Valve Characteristics on the Performance of a Piezo Pump

2013 ◽  
Author(s):  
Jean-Paul Henderson ◽  
Andrew Plummer ◽  
D. Nigel Johnston ◽  
Chris Bowen
Keyword(s):  
Flow Rate ◽  
Check Valve ◽  
Driving Frequency ◽  
Hydraulic Actuator ◽  
Orifice Area ◽  
Low Duty Cycle ◽  
Pump Flow Rate ◽  
Piezoelectric Stack Actuator ◽  
High Temperature Rise ◽  
Expected Increase

In this study, a piezoelectric stack actuator is used to oscillate a piston in a single cylinder pump. The pump is intended to directly supply a hydraulic actuator for motion control, and power output of about 1kW is targeted. Flow rectification is achieved by the use of passive check valves. The valve resonant frequency is found to have a significant effect on output flow. The expected increase in pump flow rate with driving frequency has been confirmed in simulation to hold true in a certain frequency range only. In addition, check valve size and therefore orifice area has to be adequate in order not to prohibitively restrict flow. Valve spring stiffness and valve mass need to be simultaneously optimized for the area of the valve to achieve the highest flow rate. Calculations indicate that there is a power limitation due to the high current demand and also a high temperature rise for a large continuously operated piezo stack. Thus the piezo pump appears more promising for smaller scale applications, and those that require intermittent power (i.e. a low duty cycle).

Development and Simulation of a Magnetohydrodynamic Solar Generator Operated With NaCl Electrolyte Solution

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Steffanie Jiménez-Flores ◽  
J. Guillermo Pérez-Luna ◽  
J. Joaquín Alvarado-Pulido ◽  
Antonio E. Jiménez-González
Keyword(s):  
Current Density ◽  
Check Valve ◽  
Electrical Energy ◽  
Solar Thermal ◽  
Working Fluid ◽  
Thermal System ◽  
Mhd Generator ◽  
Solar Generator ◽  
Neodymium Magnets ◽  
Solar Thermal System

Abstract A magnetohydrodynamic (MHD) generator is a device that generates electrical energy through the interaction between a conductive fluid and a magnetic field. This method of direct energy conversion allows the use of a renewable energy source such as solar energy and represents an alternative to tackle the greenhouse effect. This paper presents the development of an MHD solar generator, which is constituted by a solar thermal system and an MHD cell. The solar thermal system consists of a set of tubes with copper fins, connected in parallel and placed inside of a 1 m2 panel. In which, an electrolytic mixture of H2O and NaCl at 20% vol. was introduced as a working fluid. In order to increase the kinetic energy of the fluid, the panel was exposed to solar radiation, where it reached temperatures above 373 K and pressures above 96 kPa. This solar thermal system operates in closed cycle conditions by including a check valve in its inlet–outlet junction; in this way, the fluid travels through the MHD generator. The MHD cell was composed of a block of polytetrafluoroethylene, two cylindrical stainless-steel electrodes, and four neodymium magnets. For simulation purposes, comsol multiphysics was used to reproduce the current density produced by the MHD solar generator. Pressure and temperature quantities obtained experimentally in the MHD cell were employed as boundary conditions. The experimental maximal current density obtained corresponds to 4.30 mA/m2, and the comparison between theoretical and experimental results shows that the model fits fairly well.

Improved design of Savonius rotor for green energy production from moving Singapore metropolitan rapid transit train inside tunnel

2018 ◽  
Vol 233 (7) ◽  
pp. 2426-2441 ◽  
Author(s):  
Praveen Laws ◽  
Rajagopal V Bethi ◽  
Pankaj Kumar ◽  
Santanu Mitra
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Fossil Fuels ◽  
Numerical Study ◽  
Electrical Energy ◽  
Daily Basis ◽  
Green Energy ◽  
Subway Tunnel ◽  
Savonius Wind Turbine

Nonrenewable fossil fuels are finite resources that will ultimately deplete in near future. Nature sheds colossal amount of renewable wind energy but humans harvest a morsel. Taking this into account a numerical study is proposed on wind energy harvesting from a speeding subway train. Subways trains generate a remarkable gust of wind that can be transferred to useful electrical energy on daily basis. To this aim, a numerical analysis is modeled by placing Savonius wind turbine in a subway tunnel to crop the wind energy produced from the speeding train. The passage of train in the tunnel generates very high velocity slipstreams along the length of the tunnel. The slipstream phenomena develop a boundary layer regime that will be absorbed by the Savonius wind turbine to self-start and generate power. In the present study, a two-dimensional numerical simulation with modified turbine blade design is carried out using open source tool OpenFOAM® with PimpleDyMFoam solver coupled with six degrees of freedom mesh motion solver sixDoFRigidBodyMotion and k–ɛ turbulence modeling, to measure the amount of torque predicted by the rotor from the gust of wind produced by the speeding train in the tunnel. Being a self-start turbine with no yaw mechanism required the turbine collects air from any direction and converts it into useful power.

scholarly journals Effective Mooring Rope Tension in Mechanical and Hydraulic Power Take-Off of Wave Energy Converter

2021 ◽  
Vol 13 (17) ◽  
pp. 9803
Author(s):  
Ji Woo Nam ◽  
Yong Jun Sung ◽  
Seong Wook Cho
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Wave Energy Converter ◽  
Hydraulic Motor ◽  
Energy Converter ◽  
The Individual ◽  
Conversion Efficiencies

The InWave wave energy converter (WEC), which is three-tether WEC type, absorbs wave energy via moored cylindrical buoys with three ropes connected to a terrestrial power take-off (PTO) through a subsea pulley. In this study, a simulation study was conducted to select a suitable PTO when designing a three-tether WEC. The mechanical PTO transfers energy from the buoy to the generator using a gearbox, whereas the hydraulic PTO uses a hydraulic pump, an accumulator, and a hydraulic motor to convert mechanical energy into electrical energy. The hydraulic PTO has a lower energy conversion efficiency than that of the mechanical PTO owing to losses resulting from pipe friction and the individual efficiencies of the hydraulic pumps and motors. However, the efficiencies mentioned above are not the efficiency of the whole system. The efficiency of the whole system should be analyzed considering the tension of the rope and the efficiency of the generator. In this study, the energy conversion efficiencies of the InWave WEC installed the mechanical and hydraulic PTO devices are compared, and their behaviors are analyzed through numerical simulations. The mechanics of mechanical and hydraulic PTO applied to InWave are mathematically expressed, and the issues of the elements constituting the PTO are explained. Finally, factors to consider for PTO selection are presented.

On Cross Flow-Induced Vibration of a Flexible Cylinder

2014 ◽  
Author(s):  
H. Cen ◽  
D. S-K. Ting ◽  
R. Carriveau
Keyword(s):  
Reynolds Number ◽  
Degrees Of Freedom ◽  
Cross Flow ◽  
Mass Ratio ◽  
Flexible Cylinder ◽  
Flow Induced Vibration ◽  
Slowing Down ◽  
Mode Vibration ◽  
Inner Diameter ◽  
Multi Mode

An experiment study on the cross flow-induced vibration of a flexible cylinder with two degrees of freedom had been conducted in a towing tank. The test cylinder was a 45 cm long Tygon tubing with outer and inner diameter of 7.9 mm (5/16 in) and 4.8 mm (3/16 in), giving a mass ratio of 0.77 and an aspect ratio of 56. It was towed from rest up to 1.6 m/s before slowing down to rest again over a distance of 1.6 m in still water, covering the range of Reynolds number from 1500 to 13000 and reduced velocity from 4 to 35. Multi-mode vibration and sudden shift between different modes were observed. The vibration amplitude, frequency and mode were quantified. The results obtained during the brief constant towing speed were expressed in term of the corresponding Reynolds number or reduced velocity. These findings were cast with respect to the existing knowledge in the literature.

Application of Error Analysis Method in the Complex Vehicle Model

2012 ◽  
Vol 591-593 ◽  
pp. 584-587
Author(s):  
Shui Rong Liao ◽  
Tao Yang
Keyword(s):  
Error Analysis ◽  
Degrees Of Freedom ◽  
Lateral Acceleration ◽  
Steering Wheel ◽  
Model Parameters ◽  
Vehicle Model ◽  
Two Degrees Of Freedom ◽  
Input Amplitude ◽  
Sinusoidal Input ◽  
Set Up

A two degree of freedom input vehicle model is set up. Based on driver modeling analytical method of error analysis, step signal is taken as the input of steering angle to complex vehicle model based on CarSim, vehicle lateral acceleration is taken as as output. Meanwhile, the same steering wheel angle is taken as input as equivalent two degrees of freedom vehicle model, vehicle model parameters are optimized based on the minimum objective function. The results show that, in the same kind of speed, for steering wheel angle step input and sinusoidal input , when the input amplitude increases, the equivalent accuracy of the complex vehicle model and two degrees of freedom vehicle model will be reduced.

Elastomeric passive transmission for autonomous force-velocity adaptation applied to 3D-printed prosthetics

2018 ◽  
Vol 3 (23) ◽  
pp. eaau5543 ◽  
Author(s):  
Kevin W. O’Brien ◽  
Patricia A. Xu ◽  
David J. Levine ◽  
Cameron A. Aubin ◽  
Ho-Jung Yang ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Cost Effective ◽  
Prosthetic Hand ◽  
Prosthetic Hands ◽  
Polyurethane Composite ◽  
Compact Size ◽  
Variable Transmission ◽  
3D Printed ◽  
Force Velocity ◽  
Projection Stereolithography

The force, speed, dexterity, and compact size required of prosthetic hands present extreme design challenges for engineers. Current prosthetics rely on high-quality motors to achieve adequate precision, force, and speed in a small enough form factor with the trade-off of high cost. We present a simple, compact, and cost-effective continuously variable transmission produced via projection stereolithography. Our transmission, which we call an elastomeric passive transmission (EPT), is a polyurethane composite cylinder that autonomously adjusts its radius based on the tension in a wire spooled around it. We integrated six of these EPTs into a three-dimensionally printed soft prosthetic hand with six active degrees of freedom. Our EPTs provided the prosthetic hand with about three times increase in grip force without compromising flexion speed. This increased performance leads to finger closing speeds of ~0.5 seconds (average radial velocity, ~180 degrees second−1) and maximum fingertip forces of ~32 newtons per finger.

Comparative Study of the Linear and Non-Linear Locomotive Response

1979 ◽  
Vol 101 (3) ◽  
pp. 263-271 ◽  
Author(s):  
E. H. Chang ◽  
V. K. Garg ◽  
C. H. Goodspeed ◽  
S. P. Singh
Keyword(s):  
Dynamic Response ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Design Parameters ◽  
Suspension Systems ◽  
Damping Characteristics ◽  
Time Histories ◽  
Steady State Responses ◽  
Stiffness And Damping ◽  
State Responses

A mathematical model for a six-axle locomotive is developed to investigate its dynamic response on tangent track due to vertical and/or lateral track irregularities. The model represents the locomotive as a system of thirty-nine degrees of freedom. The nonlinearities considered in the model are primarily associated with stiffness and damping characteristics of the primary suspension system. The transient and steady-state responses of the locomotive are obtained for the linear and nonlinear primary suspension systems. The response time-histories of the locomotive obtained by integrating the generalized equations of motion are presented. The potential uses of the model are indicated for studying the influence of different design parameters and predicting subsequent dynamic response.

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