scholarly journals Impact of Cross-Tie Properties on the Modal Behavior of Cable Networks on Cable-Stayed Bridges

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Javaid Ahmad ◽  
Shaohong Cheng ◽  
Faouzi Ghrib
Keyword(s):  
Analytical Model ◽  
Design Parameters ◽  
Reference Base ◽  
Cable Network ◽  
Cable Networks ◽  
Modal Behavior ◽  
Stiffness And Damping ◽  
Main Cables ◽  
The Impact ◽  
Selection Of

Dynamic behaviour of cable networks is highly dependent on the installation location, stiffness, and damping of cross-ties. Thus, these are the important design parameters for a cable network. While the effects of the former two on the network response have been investigated to some extent in the past, the impact of cross-tie damping has rarely been addressed. To comprehend our knowledge of mechanics associated with cable networks, in the current study, an analytical model of a cable network will be proposed by taking into account both cross-tie stiffness and damping. In addition, the damping property of main cables in the network will also be considered in the formulation. This would allow exploring not only the effectiveness of a cross-tie design on enhancing the in-plane stiffness of a constituted cable network, but also its energy dissipation capacity. The proposed analytical model will be applied to networks with different configurations. The influence of cross-tie stiffness and damping on the modal response of various types of networks will be investigated by using the corresponding undamped rigid cross-tie network as a reference base. Results will provide valuable information on the selection of cross-tie properties to achieve more effective cable vibration control.

Deployment of Live Audio Services on FTTx Networks

2012 ◽  
pp. 227-248
Author(s):  
Sergio Cabrero ◽  
David Melendi ◽  
Roberto García ◽  
Xabiel G. Pañeda ◽  
Victor García
Keyword(s):  
Just In Time ◽  
Network Technology ◽  
Cable Network ◽  
Cable Networks ◽  
Underlying Network ◽  
Video Services ◽  
Audio Video ◽  
The Impact ◽  
Second Chance ◽  
Selection Of

Most live audio/video services deliver information which is produced just-in-time; thus, the deployment of these services is very challenging: there is never a second chance to broadcast the contents. Therefore, aspects such as the selection of the most suitable architecture or the impact of the underlying network technology need to be carefully studied. This chapter presents an evaluation of different architectures that may be used to deploy a live audio service on cable networks. This evaluation has been performed thanks to the development of a model of a real service that accurately reflects the behavior of the users, devices, and protocols involved in the service. The results of the evaluations can be applied to any deployment planned on a real cable network.

The Impact of Modelling Air Compressibility in the Selection of Optimal OWC Design Parameters in Site Specific Wave Conditions

2019 ◽  
Author(s):  
Irene Simonetti ◽  
Lorenzo Cappietti
Keyword(s):  
Fluid Dynamic ◽  
Experimental Tests ◽  
Design Parameters ◽  
Dynamic Simulations ◽  
Regression Approach ◽  
Wave Conditions ◽  
A Site ◽  
The Impact ◽  
Period Wave ◽  
Selection Of

Abstract The importance of properly modelling the effects of air compressibility in the selection of the optimal design parameters for an Oscillating Water Column wave energy converter is investigated. For this purpose, a wide dataset of capture width ratios, obtained from both experimental tests and Computational Fluid Dynamic simulations, is used to formulate an empirical model able to predict the performance of the device as a function of its basic design parameters (chamber width and draught, turbine damping) and of the wave conditions (wave period, wave height). A multiple non-linear regression approach is used to determine the model numerical coefficients. The data used to formulate the model include the effects of air compressibility. The impact of considering such effects on the selection of the optimal geometry of the device is evaluated and discussed by means of the model application for the optimization of a device to be installed in a site located in the Mediterranean Sea (in front of the coast of Tuscany, Italy).

Aesthetic Design for Akashi Kaikyo Bridge

1996 ◽  
Vol 1549 (1) ◽  
pp. 12-17
Author(s):  
Hiroyuki Fujikawa ◽  
Yoshitaka Kishimoto ◽  
Seigo Nasu
Keyword(s):  
Suspension Bridge ◽  
Careful Consideration ◽  
Aerodynamic Stability ◽  
Aesthetic Design ◽  
Scale Models ◽  
The Aesthetic ◽  
Light And Shadow ◽  
Main Cables ◽  
The Impact ◽  
Selection Of

The Akashi Kaikyo Bridge, part of the Honshu-Shikoku bridge project, is a suspension bridge with a center span of 1990 m. When completed in the spring of 1998, it will be the longest suspension bridge in the world. The bridge is expected to be an attractive addition to the highly urbanized area of Kobe. Therefore, the aesthetic design needed careful consideration. A suspension bridge consists of horizontal stiffening trusses, gently curving main cables, a pair of vertical towers, and anchorages. Aerodynamic stability is important in its structural design. For the Akashi Kaikyo Bridge, five types of towers were compared using 1:500 scale models. Given the fabrication and erection work for the structure, a basic truss-type design was chosen. Structural concerns dictated the shape of the stiffening trusses and the main cables. In the selection of color, the surrounding environment was studied. Further research using computer graphics and scale models and site appearance tests was carried out. Greenish-gray was finally chosen from among 30 candidate colors. To lessen the impact of the immense concrete anchorages, light and shadow effects were utilized, and vertical and horizontal indentation was adopted on the surface. The result will be structural beauty and optimum harmony of the bridge with its surroundings.

scholarly journals Analytical Breakdown Voltage Model for Partial SOI-LDMOS Transistor with Buried Oxide Step Structure

2021 ◽  
Author(s):  
Jagamohan Sahoo ◽  
Rajat Mahapatra
Keyword(s):  
Electric Field ◽  
Analytical Model ◽  
Breakdown Voltage ◽  
Point Of View ◽  
Silicon On Insulator ◽  
Oxide Semiconductor ◽  
Design Parameters ◽  
Drift Region ◽  
Two Dimensional ◽  
The Impact

Abstract We have developed a simple physics-based two-dimensional analytical Off-state breakdown voltage model of a PBOSS Silicon-On-Insulator Lateral Diffused Metal Oxide Semiconductor (SOI-LDMOS) transistor. The analytical model includes the expressions of surface potential and electric field distributions in the drift region by solving the 2D Poisson’s equation. The electric field at the Si-SiO2 surface is modified by creating additional electric field peaks due to the presence of the PBOSS structure. The uniformly distributed electric field results in improving the breakdown voltage. Further, the breakdown voltage is analytically obtained via critical electric field concept to quantify the breakdown characteristic. The model exploits the impact of the critical device design parameters such as thickness and length of the PBOSS structure, doping, and thickness of the drift region on the surface electric field and the breakdown voltage. The proposed model is verified by the results obtained from ATLAS two dimensional simulations. The analytical model is of the high potential from a physical and mathematical point of view to design high voltage SOI-LDMOS transistors for power switching applications.

Analysis of vibrations for a vibrating jaw crusher when interacting with material

2021 ◽  
pp. 26-31
Author(s):  
A. E. Shokhin ◽  
G. Ya. Panovko ◽  
I. P. Lyan
Keyword(s):  
Vibration Mode ◽  
Excitation Frequency ◽  
Design Parameters ◽  
Operating Modes ◽  
Jaw Crusher ◽  
Stable Periodic ◽  
The Impact ◽  
Excitation Conditions ◽  
Main Operating ◽  
Selection Of

A model of a vibrating jaw crusher (VJC) with self-synchronizing unbalanced vibration exciters is considered with account of the impacts between the jaws and the material being processed. Numerical modeling is used to establish the influence of the initial gap between the jaws and the material and of the velocity recovery factor upon impact on the synchronization of vibration exciters rotation and jaw vibrations, on the excitation frequency ranges of stable periodic vibroimpact regimes, and on the impact velocities between the jaws. The analysis results indicate that a change in the conditions of contact between the jaws and the material being processed leads to a change in the frequency ranges of the stable antiphase synchronization of vibration exciters rotation, as well as in the excitation frequency ranges of steady single-period vibroimpact regimes for the motion of the system, considered as the main operating modes of the VJC. The impact-like nature of the interaction between the jaws and the material being processed suggests the possible multimodality of the system, which explains some of the effects observed in practice and manifested in changes in the periodicity of the vibroimpact regime and in the vibration mode of the jaws at a constant excitation frequency. Therefore, the vibroimpact-based model proposed for the VJC and its dynamics analysis results may be used to design and improve vibrating jaw crushers with the selection of reasonable design parameters and the most effective vibration excitation conditions. The work was carried out with the financial support of the RFBR, project No. 18-08-01491_a.

scholarly journals Model Updating and Global Eigenvalue Analysis of a Tie-Bolt Rotor Using Zero-Length Contact Elements under Different Preloads

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pu Li ◽  
Qi Yuan
Keyword(s):  
Model Updating ◽  
Contact Stiffness ◽  
Great Influence ◽  
Modal Testing ◽  
Linear Spring ◽  
Modal Behavior ◽  
Stiffness And Damping ◽  
The Impact ◽  
Contact Parameters ◽  
Rotor Model

Tie-bolt rotors are composed of several disks fastened by tie bolts where contact properties have a great influence on the modal behavior. In this work, a linear spring-damper element is used to consider the contact stiffness and damping in a tie-bolt rotor. A tie-bolt rotor model is developed using the beam element and the zero-length contact element. Experimental modal testing is performed under different preloads of tie bolts. Model updating is carried out to tune the contact parameters using the Particle Swarm Optimization algorithm. Furthermore, a global eigenvalue evaluation is carried out to demonstrate the impact of the lumped spring-damper element on the modal results. Results show that a larger pretension reduces the influence of contact damping on modal parameters. Compared to antisymmetric modes, symmetric modes are more sensitive to the change of contact damping.

scholarly journals The reduction of the reaction torque of a straight four-cylinder four-stroke engine

2010 ◽  
Vol 142 (3) ◽  
pp. 82-87
Author(s):  
Ryszard MOSAKOWSKI
Keyword(s):  
The State ◽  
Propulsion System ◽  
Design Parameters ◽  
Complete Elimination ◽  
Engine Operation ◽  
Vehicle Propulsion ◽  
The Impact ◽  
Reaction Torque ◽  
Stroke Engine ◽  
Selection Of

The paper presents both the exact and simplified relations on the course of the reaction torque of a single and multi-cylinder engine, which is transmitted to the vehicle frame or foundation. The formula for the distance between the balance shafts along the vertical axes ensuring a complete elimination of the impact of the forces of inertia on the course of the reaction torque in four-stroke four-cylinder engines is derived in the paper. The criteria for selecting the optimum value of the distance are also derived in the paper. The dependence of the optimum value of the distance on the state of the engine operation and design parameters of the vehicle propulsion system is indicated in the paper. The paper proposes the selection of the optimum shafts distance, for a given type of vehicle, in areas of the engine most frequently used operating states.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Effiecency criterion for selection of design parameters of aerospace system

2016 ◽  
Vol 22 (2(99)) ◽  
pp. 48-51
Author(s):  
D.S. Kalynychenko ◽  
◽  
Ye.Yu. Baranov ◽  
M.V. Poluian ◽  
◽  
...  
Keyword(s):  
Design Parameters ◽  
Selection Of
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