Performance Upgrade of Pantograph Using Variable Stiffness Device

2010 ◽  
Author(s):  
Yoshitaka Yamashita ◽  
Mitsuru Ikeda
Keyword(s):  
Numerical Simulation ◽  
Dynamic Characteristics ◽  
Variable Stiffness ◽  
Experimental Results ◽  
New Technique ◽  
Current Collection ◽  
Simulation Results ◽  
Basic Characteristics ◽  
A New Technique

This paper proposes a new technique to improve the current collection performance of pantographs. For this purpose, the pan springs, which are usually coil springs, are replaced with variable stiffness devices. The device described in this paper is comprised of two air springs facing each other. This paper firstly outlines the method for the improvement for current collection performance and exhibits some numerical simulation results, which supports the efficacy of the method. It then presents the prototype of the variable stiffness device and shows its basic characteristics. Finally, it shows the experimental results of the dynamic characteristics control of a pantograph using the variable stiffness devices.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

scholarly journals Numerical Simulations of V-Shaped Plates Subjected to Blast Loadings: A Validation Study

2016 ◽  
Vol 10 (11) ◽  
pp. 203
Author(s):  
Mohd Zaid Othman ◽  
Qasim H. Shah ◽  
Muhammad Akram Muhammad Khan ◽  
Tan Kean Sheng ◽  
M. A. Yahaya ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Variable Mass ◽  
Blast Loading ◽  
Experimental Results ◽  
Average Difference ◽  
Simulation Results ◽  
Blast Loadings ◽  
Carrier Vehicle ◽  
Good Agreement

A series of numerical simulations utilizing LS-DYNA was performed to determine the mid-point deformations of V-shaped plates due to blast loading. The numerical simulation results were then compared with experimental results from published literature. The V-shaped plate is made of DOMEX 700 and is used underneath an armour personal carrier vehicle as an anti-tank mine to mitigate the effects of explosion from landmines in a battlefield. The performed numerical simulations of blast loading of V-shaped plates consisted of various angles i.e. 60°, 90°, 120°, 150° and 180°; variable mass of explosives located at the central mid-point of the V-shaped vertex with various stand-off distances. It could be seen that the numerical simulations produced good agreement with the experimental results where the average difference was about 26.6%.

scholarly journals Analog Low-Voltage Current-Mode Implementation of Digital Logic Gates

2003 ◽  
Vol 26 (2) ◽  
pp. 111-114 ◽  
Author(s):  
Muhammad Taher Abuelma'atti
Keyword(s):  
Power Series ◽  
Low Voltage ◽  
Logic Gates ◽  
Current Mode ◽  
New Technique ◽  
Basic Logic ◽  
Spice Simulation ◽  
Simulation Results ◽  
A New Technique ◽  
Logic Functions

In this letter a new technique is introduced for implementing the basic logic functions using analog current-mode techniques. By expanding the logic functions in power series expressions, and using summers and multipliers, realization of the basic logic functions is simplified. Since no transistors are working in saturation, the problem of fan-out is alleviated. To illustrate the proposed technique, a circuit for simultaneous realization of the logic functions NOT, OR, NAND and XOR is considered. SPICE simulation results, obtained with 3 V supply, are included

scholarly journals MEMS-Based Integrated Triaxial Electrochemical Seismometer

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1156
Author(s):  
Wenjie Qi ◽  
Bowen Liu ◽  
Tian Liang ◽  
Jian Chen ◽  
Deyong Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Ground Motion ◽  
Small Volume ◽  
Three Dimensional ◽  
Experimental Results ◽  
Good Prospect ◽  
High Symmetry ◽  
Noise Levels ◽  
Sensitivity Curves ◽  
Simulation Results

This paper presents a micro-electromechanical systems (MEMS)-based integrated triaxial electrochemical seismometer, which can detect three-dimensional vibration. By integrating three axes, the integrated triaxial electrochemical seismometer is characterized by small volume and high symmetry. The numerical simulation results inferred that the integrated triaxial electrochemical seismometer had excellent independence among three axes. Based on the experimental results, the integrated triaxial electrochemical seismometer had the advantage of small axial crosstalk and could detect vibration in arbitrary directions. Furthermore, compared with the uniaxial electrochemical seismometer, the integrated triaxial electrochemical seismometer had similar sensitivity curves ranging from 0.01 to 100 Hz. In terms of random ground motion response, high consistencies between the developed integrated triaxial electrochemical seismometer and the uniaxial electrochemical seismometer could be easily observed, which indicated that the developed integrated triaxial electrochemical seismometer produced comparable noise levels to those of the uniaxial electrochemical seismometer. These results validated the performance of the integrated triaxial electrochemical seismometer, which has a good prospect in the field of deep geophysical exploration and submarine seismic monitoring.

An Analysis of the Evaluation Methods for Thermal Transmittance of Curtain Wall System Based on Simulators

2017 ◽  
Vol 865 ◽  
pp. 383-389 ◽  
Author(s):  
Min Jung Bae ◽  
Yu Min Kim ◽  
Gyeong Seok Choi ◽  
Jae Sik Kang ◽  
Hyun Jung Choi
Keyword(s):  
Numerical Simulation ◽  
Evaluation System ◽  
Evaluation Methods ◽  
Experimental Results ◽  
Curtain Wall ◽  
Performance Evaluation System ◽  
Thermal Transmittance ◽  
Simulation Results ◽  
Primary Evaluation ◽  
Wall System

With the window rating system being enforced, window companies are required to assign window ratings to their products. As the window ratings is based on the experimental results of fenestration, they are required to spend a lot of time and money conducting laboratory tests in order to assign window ratings to all their products. Through the window performance evaluation system using simulation, the thermal transmittance of products calculated based on numerical simulation can be used in place of experimental results to obtain the window rating. To ensure the credibility of simulation results, it is necessary to use the correct evaluation methods and primary information derived from in use practice should be available for the numerical simulation. The purpose of this paper is to investigate the evaluation methods that the simulator actually uses for the thermal performance of fenestration in WINDOW/THERM. The evaluation methods used by twenty-one simulators were investigated using primary evaluation methods for numerical simulation as the criteria. This study found that most of the simulation results were not trustworthy even though they were similar to experimental results because the evaluation methods used by simulators are incorrect. Furthermore, to enhance the credibility of simulation results, the simulator should be provided with the detailed information used in practice related to the evaluation performance of numerical simulation.

The Double Pendulum Model and Nonlinear Dynamic Characteristics of the Pantograph of High-Speed Train

2013 ◽  
Vol 275-277 ◽  
pp. 767-770
Author(s):  
Hua Li ◽  
Shu Qian Cao
Keyword(s):  
Numerical Simulation ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Lagrange Equation ◽  
Variable Stiffness ◽  
Nonlinear Damping ◽  
Double Pendulum ◽  
High Speed Train ◽  
Pendulum Model ◽  
Damping Torque

In this paper, the double pendulum model of the pantograph was developed, in which a square angular velocity damping torque was used to describe the nonlinear damping torque of the hydraulic vibration damper, and the catenary was described as a variable stiffness spring. Considering the nonlinear factors caused by hydraulic damping and the interaction between the catenary and the pantograph, the motion differential equations based on the double pendulum model were established in Lagrange equation, and then were simplified. The dynamic characteristics were analyzed through numerical simulation. The result of numerical simulation shows that there are quasi-periodic motion and chaos in the system, which are both affected by the pendulum length ratio. The results are helpful to research the dynamic characteristics of the pantograph of high-speed train.

Lissajous Curve of an Auxiliary Winding Voltage Park Components for Diagnosing Multiple Open Switches Faults in Three Phase Inverter

2014 ◽  
Vol 672-674 ◽  
pp. 1224-1233 ◽  
Author(s):  
Lamiaâ El Menzhi ◽  
Abdallah Saad
Keyword(s):  
Induction Motor ◽  
New Technique ◽  
Phase Voltage ◽  
Phase Inverter ◽  
Voltage Inverter ◽  
Three Phase ◽  
Open Switch ◽  
Simulation Results ◽  
A New Technique ◽  
Three Phase Inverter

In this paper, a new technique for diagnosing multiple open switch fault in three phase voltage inverter feeding induction motor is presented. It is based on the so-called the Lissajous curve of an auxiliary winding voltage Park components. For this purpose, expressions of the inserted winding voltage and its Park components are presented. Simulation results curried out for non defected and defected inverter show the effectiveness of the proposed method.

Efficiency Metallic Leading Edge Structure Bird Strike Resistant Design

2011 ◽  
Vol 338 ◽  
pp. 84-89 ◽  
Author(s):  
Mei Ying Zhao ◽  
Jing Jing Li
Keyword(s):  
Numerical Simulation ◽  
Absorption Rate ◽  
Leading Edge ◽  
Experimental Results ◽  
Structural Quality ◽  
Bird Strike ◽  
Edge Structure ◽  
Simulation Based ◽  
Simulation Results ◽  
Resistant Structure

This article investigated a new metallic leading edge bird strike resistant structure, using corrugate board as its enhanced component to absorb more bird kinetic energy. This structure was called as Corrugate Board Leading Edge (CBLE) structure. To verify the structure’s bird strike resistant ability, numerical simulation based on the LS-DYNA was carried out, and succeeding experiments were performed. However, the experimental results were not exciting. They were not as the simulation results we expected. The reasons were analyzed through this article. Finally a rivet-relative model was created considering the influence of riveting. This model was proved to be accurate by comparing with experimental results. Based on the analysis above, an Optimized CBLE (O-CBLE) structure was used to optimize the bird strike resistant ability, the energy absorption rate of O-CBLE structure increased 11.4% while the structural quality was only slightly increased.

scholarly journals On the Broadening of Single-Layer Metasurface Bandwidth by Coupling Resonances

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2063 ◽  
Author(s):  
Humberto Fernández Álvarez ◽  
María Elena de Cos Gómez ◽  
Fernando Las-Heras Andrés
Keyword(s):  
Equivalent Circuit ◽  
Equivalent Circuit Model ◽  
Single Layer ◽  
Circuit Model ◽  
New Technique ◽  
Unit Cells ◽  
Simulation Results ◽  
A New Technique ◽  
Bandwidth Broadening

In this contribution a new technique to increase the bandwidth of metasurfaces without increasing their profile is presented. This work takes advantage of the potential multiresonant behavior of a metamaterial whose unit cells comprise nested metallization geometries in the same layer. The novelty stems from the possibility of overlapping these resonances for increasing the bandwidth (instead of obtaining a multiresonant metasurface). Several guidelines to achieve the aforementioned bandwidth broadening, which are applicable to all metasurface designs, will be provided. An equivalent circuit model will be used to better explain the presented technique; then, it will be applied to several metasurface absorbers (MTAs), showing not only a bandwidth broadening but also an absorption reinforcement. Measurements will be also presented to corroborate the simulation results.

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