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Research on key technologies for precast concrete bridge piers and bent caps
Published in Joan-Ramon Casas, Dan M. Frangopol, Jose Turmo, Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability, 2022
Z. Yin, L. Zhou, X. Li, J. Peng, X. Yan, Y. Wu
When the bent caps are divided in the transverse direction, the precast segments can be connected by dry or wet joint. For the dry joint, shear keys are necessary to provided sufficient shear resistance between two segments. In general, there are four types of shear keys, including small keyway shear key, big keyway shear key, steel shear key and corbel shear key.
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].
Effects of modification on the strength–weight ratio of standard bevel gears
Published in Mechanics Based Design of Structures and Machines, 2022
In Modification I, the tooth root width of the pinion and gear increased with micro-geometry modification. The tooth root width increased from 6.704 to 7.054 mm in the gear’s rear section (MG1). The root width has also been increased from 6.385 to 6.827 mm (MP1) at the pinion’s rear section (Figure 3). In the first modification total design, a double keyway of 8 × 4 mm was created for the gear. Also, chamfer has been defined on the rear sections of the gears. Gear width was edited from 30.17 to 29.14 mm. Pinion width was edited from 26.92 to 26.61 mm (Figure 4). The outer diameters of the gears are the same as the original standard gear. The amount of raw material required to produce gears is G1R: 1300 g for gear, P1R: 1051 g for pinion. Modified gear (MG1) weight is 432.32 g modified pinion (MP1) weight is 335.27 g.
Multi -source design change propagation path optimisation based on the multi-view complex network model
Published in Journal of Engineering Design, 2021
Ren Haibing, Li Ting, Li Yupeng, Huan Jie
As shown in Table 12, the path 1* that starts with Starter Motor (node 15) with the grey background in the third row is used as an example for result analysis from the viewpoint of reality. The function of Starter Motor (node 15) is to start the diesel engine and make it work. The electrical energy is from Starter Motor (node 15) transmitted to Piston Rings Piston Pin (node 3) and Conn Rod (node 4), which can make piston start to do work and converts electrical energy into mechanical energy. Structurally, some easily separable connections: keyway, chute, etc. exist among Starter Motor (node 15), Oil Filter (node 20), Flywheel Ring Gear (node 14), and Piston Rings Piston Pin (node 3), and the correlation strength are 0.2. Therefore, the change at Starter Motor (node 15) can be propagated to Oil Filter (node 20), Flywheel Ring Gear (node 14), Piston Rings Piston Pin (node 3), and Conn Rod (node 4). Refer to the change database provided by the enterprise, the probability of the change from Starter Motor (node 15) to Flywheel Ring Gear (node 14) is 0.1. According to the component relationship network shown in Figure 13, the criticality of Flywheel Ring Gear (node 14) in the network is 0.22, the initial impact is 0.7, thus, the change propagation intensity of the path 15–14 is 0.325, which is better than the paths from Starter Motor (node 15) to Piston Rings Piston Pin (node 3), from Starter Motor (node 15) to Conn Rod (node 4), and from Starter Motor (node 15) to Oil Filter (node 20). Thus, from the viewpoint of change propagation intensity, we prefer the path from Starter Motor (node 15) to Flywheel Ring Gear (node 14) (as shown path 1*in Table 12). Moreover, due to the differences among the values of various parameters of subsequent nodes, the selection effect of each node will eventually be reflected in the comprehensive performance of the design change propagation path. Therefore, in addition to considering the objective value of a single change propagation step, the overall objective value also needs to be considered, such as the path 2* with the grey background in the second row with the optimal change cost in Table 12. As shown in Table 13, although Starter Motor (node 15) has the lowest cost to propagate to Piston Rings Piston Pin (node 3), the subsequent path involved in propagating to Conn Rod (node 4) is better than that in propagating to Piston Rings Piston Pin (node 3). Therefore, path 2* chooses to propagate to Conn Rod (node 4).