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Sport Wheelchair Technologies
Published in Franz Konstantin Fuss, Aleksandar Subic, Martin Strangwood, Rabindra Mehta, Routledge Handbook of Sports Technology and Engineering, 2013
Franz Konstantin Fuss, Aleksandar Subic
Wheels are manufactured from lightweight metals or carbon fibres. Balls-sports chairs have two large wheels and racing chairs include an additional smaller front wheel. In essence, wheel technology is adopted from bicycles, focusing on aerodynamics and minimal mass. Three design types of wheels are available for wheelchair sports (Figure 10.1): standard spoke wheels, aero-spoke wheels and disc wheels. Standard spoke wheels have mostly flat spokes with an elliptic cross-section for reducing the aerodynamic drag. Spoke wheels are incredibly light, with a mass of only 0.2 kg and a moment of inertia of 0.0 85 kg m2. In contrast to numerous pre-tensioned metal spokes, three or four carbon-fibre aero spokes provide a continuous connection between rim and hub. Disc wheels are made of carbon fibre and are relatively heavy, with a mass of 1 kg and a moment of inertia of 0.25 kg m2. Disc wheels have an aerodynamic advantage as they generate the least drag force in windless or front-wind conditions followed by aero spokes and standard spokes. In a cross wind, the sequence reverses and disc wheels produce high drag forces, owing to their large projected area. (Jermy et al. 2008). In wheelchair rugby, the wheels are covered with spoke guards, which serve two purposes: protection of the spokes on collision, and replacement of the push rim. Wheels are cambered, which serves two purposes. Cambered wheels make wheelchairs more stable, especially when turning at higher speeds, and allow the athlete to reach the push rim at smaller shoulder angles. The disadvantage of cambered wheels is that their rolling friction coefficient is higher. The camber angle of the rear wheels influences the propulsion cycle efficiency. According to Faupin et al. (2004), higher camber angles increase residual torque, propelling time (powered push phase) and total power but decrease mean velocity.
Wheels and Tyres
Published in G. K. Awari, V. S. Kumbhar, R. B. Tirpude, Automotive Systems, 2021
G. K. Awari, V. S. Kumbhar, R. B. Tirpude
Wheels: Wheel is an most important structural member of the vehicular suspension system that supports the static and dynamic loads generated during various operating conditions of the vehicle. A wheel is a circular device that is capable of rotating on its axis, facilitating movement or transportation while supporting a load.
Application of textile fibres from tire recycling in asphalt mixtures
Published in Road Materials and Pavement Design, 2022
Jorge C. Pais, Caio R. G. Santos, Davide Lo Presti
The application of textile fibres from ground tires was evaluated through laboratory tests on specimens extracted from slabs produced in a laboratory environment. The tests were performed with several asphalt mixtures varying the asphalt binder type and content, and the fibres content. This study was developed through the following phases: The mechanical properties were evaluated through indirect tensile tests, fatigue tests, dynamic modulus, and wheel track tests.Artificial neural network modelling was used for sensitivity analysis of the indirect tensile cracking tests.Results were then used to conduct a design exercise to assess the potential advantages of using recycled tire textile fibres in asphalt mixtures for road pavements.
A novel three-dimensional wheel–rail contact geometry method in the switch panel considering variable cross-sections and yaw angle
Published in Vehicle System Dynamics, 2021
Yu Chen, Jian Wang, Jiayin Chen, Ping Wang, Jingmang Xu, Boyang An
The variable rail profiles are obtained by the analytical method in Section 2.1, then the contact point can be determined based on the variable rail cross-sections. In three-dimensional spaces, searching for the wheel–rail contact point is complex. When rail profiles can be considered as a cylindrical surface, Wang [7] developed a contact locus method to accelerate the progress by transferring the 3D wheel surface to a contact locus. The wheel is considered as a body of a revolving surface and composed of a series of rolling circles with the centerline of the wheel set axle. Each rolling circle only has a potential contact point because of geometric constraints. All potential contact points belong to a spatial curve on the wheel surface. This curve is called the ‘contact locus’.
Numerical Simulation of Water Spray Generated by Aircraft Multi-Wheels
Published in International Journal of Computational Fluid Dynamics, 2021
Xiangshan Guan, Fei Xu, Muqiu Hu, Xuanqi Ren, Xianpeng Zhang
According to the size of the tire, the double-wheels spray model is established in Hypermesh and LS-DYNA. The double-wheels spray model is simplified to double-wheels, runway and water accumulation layer. The wheel is mainly composed of an inner tube, outer tire and rim, where the outer tire is made of mooney-rivlin rubber material, the inner tube is made of elastic material, and the rim is made of rigid body material. The accumulation layer is simulated by the SPH method, where the material is Null material, and the particle spacing is 2 mm. The specific parameters of tires include 1016 mm outer diameter (D), 504 mm inner diameter (Dinner), 354 mm width (w), 100000 N load (z) and 1.22 Mpa inflation pressure (pt). The values of tire spacing (yw) are 620 mm, 720 mm and 820 mm respectively. The geometric dimensions of the water film are as follows: 200 mm width (in the X direction), 1100 mm length (in the Y direction length), and 12 mm/16 mm/20 mm depth (in the Z direction, the symbol is d). The finite element model is shown in Figure 1.