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Wheels and Tyres
Published in Andrew Livesey, Basic Motorsport Engineering, 2012
These are circular hollow rubber rings with a valve. The inner tube is used on vehicles fitted with wire-spoked, three-piece and two-piece wheels, to prevent air leakage. The inner tube is inflated inside the wheel and tyre assembly. With wire-spoked wheels a rim tape is fitted between the inner tube and the rim, to prevent puncturing by the sharp edges of the spokes. In an emergency, punctures in inner tubes can be repaired with patches; these are larger versions of bicycle patches. However, this practice is not advised and should not be carried out on high-speed vehicles.
Method of Measurement of Admittance of Composite Solid Propellants Using Impedance Tube Technique
Published in Combustion Science and Technology, 2023
S. Ganesan, S. R. Chakravarthy, B. S. Subhash Chandran
A rotary valve is designed to act as an acoustic driver to generate the standing wave inside the inner tube and is designed to work at the pressure up to 12 MPa. It consists of a stator, a rotor, set of good quality rotary seals made of poly-tetra-fluoro-ethylene (PTFE) material, two single-row ball bearings and a DC electrical motor (Figure 2). Stator is a cylindrical body with two through holes across its diameter. A rotor shaft which has 20 holes in it of diameter 4 mm is assembled exactly to match and align with the stator holes such that whenever the holes align while the rotor rotates, a continuous flow line is established for the gases to flow through it. A nitrogen cylinder is connected to the rotary valve at its one end of stator and the opposite end is connected to the inner tube where the standing wave is to be generated. The periodic alignment and misalignment of rotor holes with the stator holes, connected with the high-pressure nitrogen cylinder, pumps in the gas periodically to the inner tube which in turn generates a forward running wave. This gets reflected from the boundaries and a backward running wave is generated. These two waves collide with each other to form a standing wave which is directly measured using the pressure transducers. Now upon propellant burning, there is a slight change in the standing wave structure which is captured by the array of pressure transducers. Upon comparing with the theoretical standing wave and the experimentally obtained standing wave and minimizing the error, the admittance is measured.
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.
A new nonlinear displacement-dependent parametric model of a high-speed rail pantograph hydraulic damper
Published in Vehicle System Dynamics, 2020
Wenlin Wang, Zirong Zhou, Weihua Zhang, Simon Iwnicki
During the extension stroke of the damper, as shown by Figure 3(a), the check valve in the piston assembly is closed, while the check valve in the foot valve assembly is opened. Thus, high pressure is built up in the extension chamber, and the high-pressure oil is displaced to the reservoir through the orifice in the inner tube and to the compression chamber through the orifice array in the rod. However, with extension of the damper, the orifices in the rod become sequentially obstructed by the guide seat, causing the pressure in the extension chamber to increase; when all the orifices are shielded, the oil at maximum pressure can only be forced through the orifice in the inner tube. Simultaneously, the oil in the reservoir flows into the compression chamber with very low resistance to compensate for volume expansion of the compression chamber.