scholarly journals The substantiation of design parameters of circular curves on high-speed railways

2020 ◽  
Keyword(s):  
High Speed ◽  
Design Parameters ◽  
Circular Curves

Aerodynamic and aeroacoustic performance investigations on modified H-rotor Darrieus wind turbine

2021 ◽  
pp. 0309524X2110039
Author(s):  
Amgad Dessoky ◽  
Thorsten Lutz ◽  
Ewald Krämer
Keyword(s):  
Wind Turbine ◽  
High Speed ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
3D Models ◽  
Power Coefficient ◽  
Design Parameters ◽  
Second Phase ◽  
Vertical Axis Wind Turbine ◽  
Guide Vanes

The present paper investigates the aerodynamic and aeroacoustic characteristics of the H-rotor Darrieus vertical axis wind turbine (VAWT) combined with very promising energy conversion and steering technology; a fixed guide-vanes. The main scope of the current work is to enhance the aerodynamic performance and assess the noise production accomplished with such enhancement. The studies are carried out in two phases; the first phase is a parametric 2D CFD simulation employing the unsteady Reynolds-averaged Navier-Stokes (URANS) approach to optimize the design parameters of the guide-vanes. The second phase is a 3D CFD simulation of the full turbine using a higher-order numerical scheme and a hybrid RANS/LES (DDES) method. The guide-vanes show a superior power augmentation, about 42% increase in the power coefficient at λ = 2.75, with a slightly noisy operation and completely change the signal directivity. A remarkable difference in power coefficient is observed between 2D and 3D models at the high-speed ratios stems from the 3D effect. As a result, a 3D simulation of the capped Darrieus turbine is carried out, and then a noise assessment of such configuration is assessed. The results show a 20% increase in power coefficient by using the cap, without significant change in the noise signal.

The Engagement of Hybrid Ultra High Space Division Multiplexing with Maximum Time Division Multiplexing Techniques for High-Speed Single-Mode Fiber Cable Systems

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
P. G. Kuppusamy ◽  
Ahmed Nabih Zaki Rashed ◽  
P. Jayarajan ◽  
M. R. Thiyagupriyadharsan ◽  
...  
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Design Parameters ◽  
Control Parameters ◽  
Data Rates ◽  
Fiber Optic Communication ◽  
High Space ◽  
Optic Communication

AbstractHigh-speed single-mode fiber-optic communication systems have been presented based on various hybrid multiplexing schemes. Refractive index step and silica-doped germanium percentage parameters are also preserved during their technological boundaries of attention. It is noticed that the connect design parameters suffer more nonlinearity with the number of connects. Two different propagation techniques have been used to investigate the transmitted data rates as a criterion to enhance system performance. The first technique is soliton propagation, where the control parameters lead to equilibrium between the pulse spreading due to dispersion and the pulse shrinking because of nonlinearity. The second technique is the MTDM technique where the parameters are adjusted to lead to minimum dispersion. Two cases are investigated: no dispersion cancellation and dispersion cancellation. The investigations are conducted over an enormous range of the set of control parameters. Thermal effects are considered through three basic quantities, namely the transmission data rates, the dispersion characteristics, and the spectral losses.

Parameter study and optimization design of a hat oblique tunnel portal

2021 ◽  
pp. 095440972110140
Author(s):  
Zijian Guo ◽  
Tanghong Liu ◽  
Wenhui Li ◽  
Yutao Xia
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Pareto Front ◽  
Optimization Problem ◽  
Optimization Method ◽  
Design Parameters ◽  
Parameter Study ◽  
Buffer Structure ◽  
Tunnel Entrance ◽  
The Ideal

The present work focuses on the aerodynamic problems resulting from a high-speed train (HST) passing through a tunnel. Numerical simulations were employed to obtain the numerical results, and they were verified by a moving-model test. Two responses, [Formula: see text] (coefficient of the peak-to-peak pressure of a single fluctuation) and[Formula: see text] (pressure value of micro-pressure wave), were studied with regard to the three building parameters of the portal-hat buffer structure of the tunnel entrance and exit. The MOPSO (multi-objective particle swarm optimization) method was employed to solve the optimization problem in order to find the minimum [Formula: see text] and[Formula: see text]. Results showed that the effects of the three design parameters on [Formula: see text] were not monotonous, and the influences of[Formula: see text] (the oblique angle of the portal) and [Formula: see text] (the height of the hat structure) were more significant than that of[Formula: see text] (the angle between the vertical line of the portal and the hat). Monotonically decreasing responses were found in [Formula: see text] for [Formula: see text] and[Formula: see text]. The Pareto front of [Formula: see text] and[Formula: see text]was obtained. The ideal single-objective optimums for each response located at the ends of the Pareto front had values of 1.0560 for [Formula: see text] and 101.8 Pa for[Formula: see text].

scholarly journals Reliability Evaluation of Fan-Out Type 3D Packaging-On-Packaging

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 295
Author(s):  
Pao-Hsiung Wang ◽  
Yu-Wei Huang ◽  
Kuo-Ning Chiang
Keyword(s):  
Finite Element ◽  
Thermal Cycling ◽  
Glass Substrate ◽  
High Speed ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Design Parameters ◽  
Time To Failure ◽  
Wafer Level ◽  
Fine Pitch

The development of fan-out packaging technology for fine-pitch and high-pin-count applications is a hot topic in semiconductor research. To reduce the package footprint and improve system performance, many applications have adopted packaging-on-packaging (PoP) architecture. Given its inherent characteristics, glass is a good material for high-speed transmission applications. Therefore, this study proposes a fan-out wafer-level packaging (FO-WLP) with glass substrate-type PoP. The reliability life of the proposed FO-WLP was evaluated under thermal cycling conditions through finite element simulations and empirical calculations. Considering the simulation processing time and consistency with the experimentally obtained mean time to failure (MTTF) of the packaging, both two- and three-dimensional finite element models were developed with appropriate mechanical theories, and were verified to have similar MTTFs. Next, the FO-WLP structure was optimized by simulating various design parameters. The coefficient of thermal expansion of the glass substrate exerted the strongest effect on the reliability life under thermal cycling loading. In addition, the upper and lower pad thicknesses and the buffer layer thickness significantly affected the reliability life of both the FO-WLP and the FO-WLP-type PoP.

Development of High-Speed Response Electromagnetic Linear Actuator Using for Pneumatic Control Valve

2014 ◽  
Vol 532 ◽  
pp. 41-45 ◽  
Author(s):  
Myung Jin Chung
Keyword(s):  
Optimal Design ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Design Method ◽  
Control Valve ◽  
Design Parameters ◽  
Linear Actuator ◽  
Analytic Model ◽  
Electromagnetic Linear Actuator ◽  
Quadratic Programming Method

Analytic model of electromagnetic linear actuator in the function of electric and geometric parameters is proposed and the effects of the design parameters on the dynamic characteristics are analyzed. To improve the dynamic characteristics, optimal design is conducted by applying sequential quadratic programming method to the analytic model. This optimal design method aims to minimize the response time and maximize force efficiency. By this procedure, electromagnetic linear actuator having high-speed characteristics is developed.

Peculiarities of the Power Hydrocannon Operation

2003 ◽  
Author(s):  
G. A. Atanov ◽  
A. N. Semco ◽  
O. P. Petrenko ◽  
E. S. Geskin ◽  
V. Samardzic ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Technique ◽  
Design Parameters ◽  
Jet Formation ◽  
Pressure Fields ◽  
Fluid Jets

The paper is concerned with improvement of the devices for formation of super high-speed fluid jets termed hydro cannon. Two modes of the energy injection into the fluid (the piston impact and the powder explosion) are considered and advantages of the use of the gunpowder are determined. A numerical technique for prediction of the jet formation, developed previously by one of the authors is applied for description of the velocity and pressure fields within the hydro cannon. Effect of the design parameters on the fluid acceleration is explored and suggestions for improvement of the hydro cannon design are made.

Airbag Inflators

1999 ◽  
Author(s):  
William G. Broadhead ◽  
D. Theodore Zinke
Keyword(s):  
High Speed ◽  
Motor Vehicle ◽  
Seat Belt ◽  
Design Parameters ◽  
Steering Wheel ◽  
Instrument Panel ◽  
Highway Traffic ◽  
National Highway Traffic Safety ◽  
Column Collapse ◽  
Wide Range

Abstract The design of an airbag restraint system presents a classic engineering challenge. There are numerous design parameters that need to be optimized to cover the wide range of occupant sizes, occupant positions and vehicle collision modes. Some of the major parameters that affect airbag performance include, the airbag inflator characteristics, airbag size and shape, airbag vent size, steering column collapse characteristics, airbag cover characteristics, airbag fold pattern, knee bolsters, seat, seat belt characteristics, and vehicle crush characteristics. Optimization of these parameters can involve extremely costly programs of sled tests and full scale vehicle crash tests. Federal Motor Vehicle Safety Standards (FMVSS) with regard to airbag design are not specific and allow flexibility in component characteristics. One design strategy, which is simplistic and inexpensive, is to utilize a very fast, high output gas generator (inflator). This ensures that the bag will begin restraining the occupant soon after deployment and can make up for deficiencies in other components such as inadequate steering column collapse or an unusually stiff vehicle crush characteristic. The use of such inflators generally works well for properly positioned occupants in moderate to high-speed frontal collisions by taking advantage of the principle of ridedown. When an airbag quickly fills the gap between the occupant and the instrument panel or steering wheel it links him to the vehicle such that he utilizes the vehicle’s front-end crush to help dissipate his energy, thus reducing the restraint forces. Unfortunately, powerful airbag systems can be injurious to anyone in the path of the deploying airbag. This hazard is present for short statured individuals, out of position children or any occupant in a collision that results in extra ordinary crash sensing time. Currently, the National Highway Traffic Safety Administration (NHTSA) is proposing to rewrite FMVSS 208 to help reduce such hazards.

Vibration-Based Early Crack Diagnosis With Machine Learning for Spur Gears

2020 ◽  
Author(s):  
Fatih Karpat ◽  
Ahmet Emir Dirik ◽  
Onur Can Kalay ◽  
Oğuz Doğan ◽  
Burak Korcuklu
Keyword(s):  
Machine Learning ◽  
Fault Diagnosis ◽  
High Speed ◽  
Crack Detection ◽  
Power Transmission ◽  
Calculated Data ◽  
Design Parameters ◽  
Tooth Stiffness ◽  
Vibration Responses ◽  
Root Crack

Abstract Gear mechanisms are one of the most significant components of the power transmission systems. Due to increasing emphasis on the high-speed, longer working life, high torques, etc. cracks may be observed on the gear surface. Recently, Machine Learning (ML) algorithms have started to be used frequently in fault diagnosis with developing technology. The aim of this study is to determine the gear root crack and its degree with vibration-based diagnostics approach using ML algorithms. To perform early crack detection, the single tooth stiffness and the mesh stiffness calculated via ANSYS for both healthy and faulty (25-50-75-100%) teeth. The calculated data transferred to the 6-DOF dynamic model of a one-stage gearbox, and vibration responses was collected. The data gathered for healthy and faulty cases were evaluated for the feature extraction with five statistical indicators. Besides, white Gaussian noise was added to the data obtained from the 6-DOF model, and it was aimed at early fault diagnosis and condition monitoring with ML algorithms. In this study, the gear root crack and its degree analyzed for both healthy and four different crack sizes (25%-50%-75%-100%) for the gear crack detection. Thereby, a method was presented for early fault diagnosis without the need for a big experimental dataset. The proposed vibration-based approach can eliminate the high test rig construction costs and can potentially be used for the evaluation of different working conditions and gear design parameters. Therefore, catastrophic failures can be prevented, and maintenance costs can be optimized by early crack detection.

Design of an adaptive neuro-observer-based feedback controller for high-speed trains with parametric uncertainties

2018 ◽  
Vol 233 (8) ◽  
pp. 765-782
Author(s):  
Meera Patel ◽  
Bhanu Pratap
Keyword(s):  
High Speed ◽  
Upper Bounds ◽  
Formal Proof ◽  
Adaptive Observer ◽  
Stability And Convergence ◽  
Design Parameters ◽  
High Speed Train ◽  
Feedback Form ◽  
Dynamic Surface ◽  
Control Approach

An adaptive observer-based controller design for the nonlinear model of a high-speed train is demonstrated in this paper. A high-speed train belongs to the class of multivariable and coupled dynamic system with a higher degree of nonlinearities and uncertainties. The radial basis function neural network is used for the approximation of these nonlinearities and uncertainties. Using this approximation, an adaptive neuro-observer is designed for the estimation of the unavailable states of the high-speed train for measurement. Using one-to-one nonlinear mapping, the high-speed train plant and the adaptive neuro-observer are remodelled in a pure feedback form without any constraints on states. On the basis of the adaptive neuro-observer, an adaptive dynamic surface controller is designed for the high-speed train system. The upper bounds of the actual controller gains of the high-speed train need not be known whereas the lower and upper bounds of the virtual controller gain require prior knowledge. The tuning of the design parameters has been done online in the proposed observer/controller. The closed-loop stability and convergence have been analysed through a formal proof based on the Lyapunov approach. The enhanced performance of the high-speed train with the proposed controller is compared with the backstepping control approach and demonstrated using simulation studies.

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