Hub Design Research Articles

Design of an 8-speed internal gear hub with a rotary control mechanism for bicycles

Design of an 8-speed internal gear hub with a rotary control mechanism for bicycles

Description and Computer Modeling of a Ball-and-Socket Hub That Enables Teetering for Three-Bladed Wind Turbines

A horizontal axis wind turbine with a ball-and-socket hub is disclosed. The hub enables horizontal axis turbines with two or more blades to teeter in response to wind shear gradients. Computer modeling was done using existing and modified fast code in order to compare the new hub design with existing designs. Results show that a three-bladed turbine with the ball-and-socket hub provides very significant reductions in out-of-plane bending loads applied to the main shaft in comparison to a three-bladed turbine with a rigid hub. Results also show that the new hub design provides significant reductions in the out-of-plane loads applied to the blades. A blade fatigue study using a rainflow counting of multi-axial torque contributions at the blade root was performed in order to assess the impact of these reductions, and results show that the three-bladed turbine equipped with a ball-and-socket, teetering hub provides for very significant reductions in lifetime blade damage in comparison to existing wind turbine designs due to a combination of factors. The first factor is that teetering largely eliminates the cyclic variations in out-of-plane torque on the blades that are observed with rigid hubs. Here, the fatigue study shows that the three-bladed wind turbine with a teetering hub provides for an approximate sixfold reduction in lifetime blade damage in comparison to a three-bladed turbine with a rigid hub. The second factor is that the addition of a third blade reduces the load on each blade by one-third. Here, the fatigue study shows that a three-bladed turbine with a teetering hub provides for an approximate fourfold reduction in lifetime blade damage in comparison to a two-bladed turbine with a teetering hub.

Robust hub design to prevent mechanical contact between the hub and sleeve of FDBs in an HDD due to disc clamping force

We investigated the rotational harmonic source of the runout in a 2.5? hard disk drive (HDD) with a height of 5 mm, especially at low rotating speeds. After disassembling the HDD, circumferential scratches between the upper thrust surface of the hub and sleeve were observed. Through a finite element static analysis of the hub, the deflection resulting from disc clamping force was identified as a source of mechanical contact between the rotating hub and the stationary sleeve. This was determined to generate large-amplitude harmonics in the runout and flying height lower than design values. To prevent mechanical contact between these components, we propose a robust hub design in which the hub thickness radially decreases between the inner and outer thrusts. And HDD spindle motor was prototyped with the proposed hub. Experiments showed that the flying height is increased almost same as design value and the harmonics of the runout were significantly reduced, even at low rotating speeds. After disassembling the prototyped HDD spindle motor, we confirmed that there were no scratches on the surface of the thrust bearing.

Benefits of Nonaxisymmetric Endwall Contouring in a Compressor Cascade With a Tip Clearance

This paper describes the design of a nonaxisymmetric hub contouring in a shroudless axial flow compressor cascade operating at near stall condition. Although an optimum tip clearance (TC) reduces the total pressure loss, further reduction in the loss was achieved using hub contouring. The design methodology presented here combines an evolutionary principle with a three-dimensional (3D) computational fluid dynamics (CFD) flow solver to generate different geometric profiles of the hub systematically. The resulting configurations were preprocessed by GAMBIT© and subsequently analyzed computationally using ANSYSFluent©. The total pressure loss coefficient was used as a single objective function to guide the search process for the optimum hub geometry. The resulting three dimensionally complex hub promises considerable benefits discussed in detail in this paper. A reduction of 15.2% and 16.23% in the total pressure loss and secondary kinetic energy (SKE), respectively, is achieved in the wake region. An improvement of 4.53% in the blade loading is observed. Other complimentary benefits are also listed in the paper. The majority of the benefits are obtained away from the hub region. The contoured hub not only alters the pitchwise static pressure gradient but also acts as a vortex generator in an effort to alleviate the total pressure loss. The results confirm that nonaxisymmetric contouring is an effective method for reducing the losses and thereby improving the performance of the cascade.

Optimal Design of Multicarrier Energy Systems Considering Reliability Constraints

An energy hub, which receives, converts, stores, and delivers different energy carriers by means of a variety of energy converters and/or storage elements, is one of the most important concepts in multicarrier energy systems. For cost-effective and reliable supply of energy to loads in multicarrier energy systems, the problem of selecting different components forming the hub (referred to as hub design) and their operation is of great importance. In this paper, a comprehensive linearized model for optimal design and operation of energy hubs considering reliability constraints is proposed. Adequacy indices and maximum-allowable loss of load probability (LOLP) in case of single contingency are checked and different reliability constraints are introduced in the optimization process to satisfy the required level of reliability for different load types. Finally, the proposed method is applied on a test case considering electrical and thermal loads. The obtained results show the ability of the proposed method in meeting energy demand while respecting reliability constraints.

The single allocation hub location problem: a robust optimisation approach

Design of hub–and–spoke networks or the hub location problem is one of the most important problems in operational research and has many applications in different areas of transportation, logistics, and telecommunications. In this paper, a relatively new version of the single allocation hub location problem is addressed, in which quantity of the commodity flows between pairs of customer nodes are of stochastic nature. The objective here is to determine the number, location, and capacity of the hubs and also to allocate the customers to these hubs in such a way that transferring all the commodities in the network is ensured with a very high probability (capacity constraints associated with the hubs are not violated). At the same time, total expected system–wide costs will be minimised. A robust optimisation approach is employed to model the problem with a standard optimisation package being used to solve it. Results obtained via numerical experiments show the capability of the presented robust model to immunise the system against violation of capacity constraints with a relatively small cost increase, known as the robustness cost. [Received 14 October 2012; Revised 16 September 2013; Accepted 21 September 2013]

A Sustainable Planning Approach to Resolving Transportation Hub Problems in Egyptian Cities “Proposed Measurement Matrix”

The research study discusses the environmental aspects of automated and pedestrian transport that need to be addressed when devising general and detailed urban plans, particularly for new urban conglomerations. It describes the adverse effects resulting from motor vehicles dominating roads and highways, including environmental hazards such as air and noise pollution, and identifies environmental concerns to be taken into account in the planning of automated and pedestrian traffic routes and parking spaces and underlines the need for upgrading transport and traffic policies in new urban conglomerates. The study focuses on environmental issues that can be resolved through the application of laws, policies and implementation mechanisms. It also identifies environmental considerations that should be included in all general urbanization plans, pointing out that the review of these issues by environment experts (before and during plan implementation) is a key developmental approach to resolving transportation hub problems in Egypt. In addition, the study presents an account of the components and basic principles of transportation hub design and the international criteria used in assessing the sustainability of transport routes. Local and international examples of sustainable transportation hubs are used as a reference to help in formulating the principal findings and conclusions that constitute the developmental approach to resolving this problem.

Process and Property of Superplastic Mould Forged AZ80 Wheel Hub

Automobile wheel hub of Mg alloy with single-step extrusion-forging process was developed, and the microstructure and mechanical properties after heat treatment were investigated. The forged hubs have a hub wall of as thin as 3mm, and 4-7kg lighter than that of Al alloy wheel hub with a same size and design of each wheel hub, that would lead remarkable reduction of fuel consumption. The tensile strength larger than 308 MPa, good corrosion fatigue and impacting resistance sampled from the hubs obtained.

Physics-Based Modeling of Maneuver Loads for Rotor and Hub Design

A hybrid Navier–Stokes free-wake computational-fluid-dynamics methodology, coupled with a multibody dynamics analysis code, has been applied to the UH-60A rotor to study the loads developed during a severe diving turn maneuver (flight counter 11680) characterized by a mean advance ratio of 0.388 and a mean load factor of 1.48. The helicopter undergoing flight counter 11680 experiences the most severe pitch-link loads and root torsional moments recorded in the NASA/Army UH-60A Airloads Program. The feasibility of a quasi-steady loosely coupled approach for predicting severe maneuver loads was explored for predicting critical aerodynamic and aeroelastic phenomena. The structural model is first validated through measured airloads, which helps in decoupling the physics of structural dynamics and aerodynamics. The blade aeromechanical loads, push-rod loads, and harmonic content of blade structural loads for a rotor revolution characterized by peak load factor (revolution 12) have been examined in detail. The prediction of advancing blade-stall phenomena unique to severe maneuvers and the extensive occurrence of stall are examined using contours plots of sectional airloads and through comparisons of surface pressure values.

Design of a six-speed transmission hub with an integrated brushless permanent-magnet motor used for electric bicycles

Purpose – The electric motor and multi-speed transmission hub are essential components for an electric bicycle. Traditionally, these two devices have been designed and manufactured independently. The purpose of this study is to propose a novel electromechanical device that artfully integrates an exterior-rotor brushless permanent-magnet (BLPM) motor into a transmission hub to become a compact structural assembly. Design/methodology/approach – A novel design that integrates a three-phase, 20-pole/18-slot exterior-rotor BLPM motor with a multi-speed transmission hub composed of a six-link, two-degrees-of-freedom (2-DOF) compound planetary gear train (PGT) is presented in this study to overcome inherent drawbacks of existing designs. An analytical approach, based on fundamental circuits, is developed to synthesize the clutching sequences and numbers of teeth of all gears of the PGT. Findings – The integrated device provides six forward speeds, including two underdrives, two direct drives, and two overdrives, as well as two drive modes: the motor-drive mode and the human-drive mode, for electric bicycles. The main feature of the proposed design is the spur gear teeth merged with the pole shoes of the stator to dramatically minimize the detent torque, which is an oscillatory torque that always induces vibration and acoustic noise of the BLPM motor. Originality/value – The gear teeth on the pole shoes of the stator provide functions not only for transmission, but also act as dummy slots for adjusting the magnetostatic field of the BLPM motor to effectively reduce the detent torque. The peak value of the detent torque of the integrated design is only 9 percent of the original BLPM motor with identical magnet properties and motor dimensions. Such a feature is contributive in suppressing the vibration and acoustic noise of the electric bicycle's BLPM motor. A BLPM motor rated at 310 W and 250 r/min for the integrated device is presented and analyzed by using the commercial finite-element package Ansoft/Maxwell 2D Field Simulator.

Study on Influencing Factors of Passenger Transfer and Transfer Volume in Comprehensive Passenger Transport Hub

Comprehensive passenger transport hub, the intersection of various means of transportation, its main function is to achieve "zero distance" transfer among different transportation means, meet travelers needs for efficient, safe, convenient and comfortable transfer, and maximize the services level of urban passenger transport. This paper conducts a research on influencing factors of passenger transfer in comprehensive passenger transport hub and the transfer volume of different transportation means. The result not only provides technical support for design of comprehensive passenger transport hub in future, but also shows application value in optimizing facilities of hub, and improving pedestrian traffic and self-organization science.

Design and Enhancement of Radiofrequency Cannula (RC) for Chronic Pain Management

The purpose of this paper is to give an overview of radiofrequency procedure, the main components of the procedure, critical issue concern with existing cannula design and proposed methodology in design and enhancement. The literature on radiofrequency procedure has been reviewed. The main issue or problem in existing design related to placement of cannula to target nerves which are ability to firmly hold the cannula and adjustment of the cannula to the target nerve. This study proposes the fabrication prototype cannula hub using Fused Deposition Modeling (FDM) machine. Essentially, this study may benefit a lot in providing alternative design of the cannula hub while promising a better performance of RF cannula.

A Compact Planar Inverted-F Antenna for Octa-Band Operations of Smart Handsets

This paper applies planar inverted-F antenna (PIFA) to design a smart handset antenna in accordance with octa-band operations, as GSM 850 (824-894 MHz), GSM 900 (880-960 MHz), GSM 1800/1900, DCS 1800 (1710-1880 MHz), PCS 1900 (1850-1990 MHz), UMTS (1920-2170 MHz), IEEE 802.11b WLAN (2400-2484 MHz) and LTE (700 MHz/2300 MHz/2600 MHz) band operations for S11 -6 dB. The entire antenna is 75 × 22 × 5.8 mm3 with one-quarter wavelength design of hub. With the inter-coupling between dual branch circuit radiation and multiple branch circuit radiation, the wideband for GSM 1800/1900, DCS, PCS, UMTS, IEEE 802.11b WLAN and LTE 700/2300/2600 is generated. When integrating with mobiles, the designed ground plane area is also taken into consideration. In this case, the ground plane area can be increased in accordance to the system motherboard.

Life Estimation of Hub Bearing Unit Based on Test Load Spectrum

In the paper, the steady-state steering dynamics model of the cars is firstly established. Then, three degree of freedom model of double row angle contact ball bearing is established. Based on the mathematical model and load spectrum, wheel hub bearing unit service life is calculated and estimated. The analysis results of the service life influencing factors have an important guiding significance for the design and use of hub bearing unit.

Water Tunnel Flow Diagnostics of Wake Structures Downstream of a Model Helicopter Rotor Hub

A scaled model of a notional rotor hub design was tested at one-third- and two-thirds scale Reynolds number with reference to a large helicopter at an advance ratio of 0.2 in the 48” Garfield Thomas Water Tunnel (GTWT) at the Applied Research Laboratory (ARL) at Penn State University. The main objectives of the experiment were to understand the spatial- and temporal content of the unsteady wake downstream of a rotor hub up to a distance corresponding to the empennage of a large helicopter. Measurements included total hub drag and flow diagnostics involving PIV, SPIV and LDV at several locations downstream of the model rotor hub. Computations of the rotor hub flow were also performed by Sikorsky Aircraft and compared with the experimental results. Various flow structures were identified and linked to geometric features of the hub model. The most prominent structures were two-per-revolution (scissors) and four-per-revolution (main hub arms) vortical structures shed by the hub. Both the two-per-revolution and four-per-revolution structures persisted far downstream of the hub, but the rate of dissipation was greater for the four-per-rev structure. This work provides an extensive dataset for enhanced understanding of the fundamental physics underlying rotor hub flows and serves as validation data for future CFD analyses in the rotorcraft community.

Energy Hub Based on Nuclear Energy and Hydrogen Energy Storage

An ‘energy hub’ comprises of the interactions of different energy loads and sources for power generation, storage, and conversion. This paper presents an energy hub consisting of nuclear plants, wind turbines, solar panels, biomass reactors, electrolyzers, and fuel cells. The hub serves to replace existing coal-based power generating facilities to meet electricity and hydrogen demands for industrial and transportation sectors, as projected in 2030. Equipment sizing and costing analysis for different energy production technologies and hydrogen storage were considered using Matlab/Simulink. Several energy hub designs with various technological combinations were analyzed, and a profitability analysis was conducted to evaluate the feasibility of each energy hub. The proposed models also evaluate the environmental benefits of the future energy hub and outline the best hub configurations. It was found that the most economical energy hub is when nuclear reactor was operated throughout the year at a capacity near...

A prototype catheter designed for ultraviolet C disinfection

Disinfection of the intraluminal space of single-lumen polymer tubes can be obtained by ultraviolet C (UVC) light exposure from an external light source. In existing catheters UVC disinfection is hampered by the design of the catheter hub and tube connector. To demonstrate that it is possible to design a single-lumen catheter with a hub, tube connector and tube parts that can be UVC-disinfected throughout its entire lumen. Two single-lumen catheters were designed: one control and one for UVC exposure. They were contaminated with Pseudomonas aeruginosa (10(4)-10(5) cfu/mL) before UVC light exposure, sampling and plate counting. Two minutes of UVC exposure was sufficient to obtain 4 log10 disinfection for the full-length prototype catheter. This exposure corresponds to ∼40 mJ/cm(2) at the catheter tip and indicates that even shorter exposure times can be achieved. It is possible to design catheters that can be disinfected throughout the entire lumen. UVC light exposure could be useful as a decontamination method for catheters in clinical use.

Design of an energy hub based on natural gas and renewable energy sources

SUMMARY This paper presents a simulation model for an energy hub consisting of natural gas (NG) turbines as the main sources of energy (including both electricity and heat) and two renewable energy sources—wind turbines (WTs) and photovoltaic (PV) solar cells. The hub also includes water electrolyzers for hydrogen production. The hydrogen serves as an energy storage medium that can be used in some transportation applications, or it can be mixed with the NG feed stream to improve the emission profile of the gas-turbine unit. The capacity of the designed hub is meant to simulate and replace the coal-fired Nanticoke Generating Station with a NG-fired power plant. Therefore, the aim of this work is to develop a simulated model that combines different energy generation technologies, which are evaluated in terms of the total energy produced, the cost per kWh of energy generated, and the amount of emissions produced. The proposed model investigates the benefits, both economic and environmental, the technological barriers, and the challenges of energy hubs by developing several scenarios. The simulation of these scenarios was done using General Algebraic Modeling System (GAMS®). Although the software is strongly known for its optimization capability, the mixed complementary problems solver makes it a strong tool for solving equilibrium problems. Excess energy produced during off-peak demand by WTs and PV solar cells was used to feed the electrolyzer to produce H2 and O2. The proposed approach shows that a significant reduction in energy cost and greenhouse gas emissions were achieved, in addition to the increased overall efficiency of the energy hub. Out of the examined three scenarios, Scenario C appeared to be the most feasible option for a combination of renewable and non-renewable technologies as it did not only produce hydrogen, but also provided electricity at relatively lower prices. Copyright © 2013 John Wiley & Sons, Ltd.

Interchange Design of Hub of Zhoukou South in Zhoukou of Daguang Expressway

This study introduces the general situation of Hub interchange design of Daguang highway in the south of Zhoukou and lists 2 design schemes, the best scheme is selected by comparison and it also introduces the design situation of the bridge, it mainly introduces bridge opening layout, technical standards, design main point and structure calculation.

Design and Analysis of a Novel Speed-Changing Wheel Hub with an Integrated Electric Motor for Electric Bicycles

The aim of this paper is to present an innovative electromechanical device which integrates a brushless DC (BLDC) hub motor with a speed-changing wheel hub stored on the rear wheel of an electric bicycle. It combines a power source and a speed-changing mechanism to simultaneously provide functions of power generation and transmission for electric bicycles. As part of the proposed integrated device, the wheel hub consists of a basic planetary gear train providing three forward speeds including a low-speed gear, a direct drive, and a high-speed gear. Each gear is manually controlled by the shift control sleeve to selectively engage or disengage four pawl-and-ratchet clutches based on its clutching sequence table. The number of gear teeth of each gear element of the wheel hub is synthesized. The BLDC hub motor is an exterior-rotor-type permanent-magnet synchronous motor. Two-dimensional finite-element analysis (FEA) software is employed to facilitate the motor design and performance analysis. An analysis of the power transmission path at each gear is provided to verify the validity of the proposed design. The results of this work are beneficial to the embodiment, design, and development of novel electromechanical devices for the power and transmission systems of electric bicycles.