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Mechanical principles of dynamic engineering systems
Published in Alan Darbyshire, Charles Gibson, Mechanical Engineering, 2023
Alan Darbyshire, Charles Gibson
For one revolution of the wheel and axle, the effort moves a distance equal to the wheel circumference and the load is raised through a distance equal to the axle circumference (Figure 2.68). VR=Circumference of wheelCircumference of axle=πD1πD2VR=D1D2
Simple Machines
Published in G. Boothroyd, C. Poli, Applied Engineering Mechanics, 2018
A wheel and axle consists of a wheel attached to a smaller-diameter shaft or axle which turns with the wheel. A door knob, a steering wheel, and a screwdriver bit in a brace are common examples of a wheel and axle. Figure 6.5 shows a free-body diagram for a wheel and axle. The force applied to the wheel is denoted by Fp, while the load force applied to the shaft is denoted by Fι. For static equilibrium, the sum of the moments about the axis of the wheel and axle must be zero, so that Fla=Fpb
Investigation of a wheel-rail roller rig for wheel-track defect detection
Published in Vehicle System Dynamics, 2023
Jianbo Li, Hongmei Shi, Qiyao Guo
The wheel module of the wheel-rail roller rig is composed of the wheel, axle, axle box, end covers, springs, cross beam and connecting rod. The wheel diameter is 230 mm, and it is made of 55 steel, which is medium carbon steel with high strength and good wear resistance in China National Standard. The wheel is mounted on the axle by a flat key. The bearings of the wheel axle are deep groove ball bearings that are suitable for small friction resistance and high-speed revolving conditions. There are four springs fixed by bolts between the axle box and the cross beam, which simulate the primary suspension system of the vehicle. The connecting rod mechanism is used to fix the position of the axle box. It should be noted especially that the end cover of the wheel axle box can be disassembled to facilitate the replacement of the wheel with different defects. The axle box and the cross beam in the wheel module are connected by springs and bolts, and the axle of the wheel has a lateral degree of freedom in the axle box, as a consequence, the wheel has a lateral movement. The special shape of the wheel can also restrict the lateral movement of the wheel.
Optimisation of wheel profile of variable gauge high-speed trains
Published in Vehicle System Dynamics, 2023
Yayun Qi, Huanyun Dai, Feng Gan, Hao Gao
The variable gauge high-speed trains are mainly accomplished by the mechanism on the wheelset, which consists of the wheelset axle, the wheels, the sleeves and the spline keyways, with the wheel over-fitted on the sleeve and the sleeve fitted to the axle with clearance. The torque is transmitted via the spline keyway between the sleeves and the axle, as shown in Figure 1(a). When the gauge changes, the wheel and the sleeve lateral move together. The wheelset is modelled by the axle and the two wheels independently, considering the clearance between the axle and the sleeve, and considering the sleeve and the wheel as a single unit. While the variable distance between the backs of wheel flanges requires separate modelling of the left and right wheel and axle. Piecewise linear spring-damped parallel force elements were used to model the sleeve and wheel axle clearance, including axial (lateral) and circumferential (rotational), which is shown in Figure 1(b). The displacement replaces the clearance between the wheel axle and the sleeve. The force replaced the force between the wheel axle and sleeve. The entire wheelset is modelled as shown in Figure 1(c). The wheelset model is built and imported as a substructure into the full vehicle dynamic model. The detail is referred in [20].
Optimization of vibration absorbers for the suppression of rail corrugation in the sharp curved section with Cologne-egg fasteners
Published in Vehicle System Dynamics, 2023
Jia Xu, Xiaolu Cui, Haohao Ding, Pengyu Bao, Tong Li, Chuanping Tang, Xiangyang Xu
According to the dynamic characteristics of the vehicle-track system obtained by the dynamic simulation in the sharp curved section, the finite element model of the wheel-rail system in the sharp curved section with Cologne-egg fasteners is built in Figure 3. It should be noticed that the leading wheelset is mainly constructed here, in which the LM wheel profile is adopted and the rolling radius is 0.42 m. The interference fit is set between the wheel and axle. The vertical and the lateral suspension forces can be determined by the dynamic analysis. Besides, the rail length is selected as 31.25 m and rail ends are pinned, where the wheel is set in the rail mid-position to avert the boundary effects [30]. The wheel-rail contact is set as ‘hard’ contact and ‘penalty’ friction formulation, and the friction coefficient is 0.4 [31]. Moreover, the Cologne-egg fasteners are simulated by spring-damper units and the fastener spacing is set as 625 mm.