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Roller Rigs
Published in Simon Iwnicki, Maksym Spiryagin, Colin Cole, Tim McSweeney, Handbook of Railway Vehicle Dynamics, 2019
Paul D. Allen, Weihua Zhang, Yaru Liang, Jing Zeng, Henning Jung, Enrico Meli, Alessandro Ridolfi, Andrea Rindi, Martin Heller, Joerg Koch
The yaw damper adds a strong non-linearity in the dynamic force outputs with respect to the excitation and has a significant effect on the vehicle system dynamics. In order to examine this effect, the critical speeds of the vehicle from the rig test and simulations were compared when all eight yaw dampers mounted on the test car were removed. As shown in Figure 19.12b, the bogie hunting appears at quite a low speed, with large lateral movement of the wheelset. The simulated limit cycle of lateral movement of the wheelset resulting from the Polach model is much closer to the test results, followed by the S.H.E. model, while the FASTSIM model predicts a lower critical speed. The solid markers in Figure 19.12b present the results when increasing the vehicle speed, while the hollow markers correspond to the cases when slowing down the vehicle. It is seen that the vehicle experiences similar stability performance at a certain speed regardless of using the increasing speed and slowing down method, which means the hollow and solid markers merge with each other at some speeds.
Practical control law design for aircraft using multivariable techniques
Published in Mark B. Tischler, Advances in Aircraft Flight Control, 2018
James D. Blight, R. Lane Dailey, Dagfinn Gangsaas
Occasional ride discomfort was reported during early passenger service of the Boeing 767 commercial jet transport. It was due to a small-amplitude, sustained yawing oscillation that occurred only during high altitude cruise flight when both the yaw damper and lateral autopilot were engaged. The yaw damper increases the damping of the dutch roll mode (involving yaw and roll angle oscillations) of the aircraft using the rudder as a single control. The yaw damper is normally engaged both in manual and automatic flight. During automatic flight, the lateral autopilot is engaged and it controls heading or track angle using the combination of left and right ailerons as a single control.
Research on the Characteristics of Wheel Hollow Wear and Suppression Measures of High-Speed Trains
Published in Tribology Transactions, 2023
Yayun Qi, Huanyun Dai, Ye Song, Fubing Zhang, Sisi Lu
The anti-yaw damper parameters have an important influence on vehicle dynamics, while the anti-yaw damper can have some influence on wheel wear. This section focuses on two parameters of damping characteristics and nodal stiffness. First, wheel wear is analyzed for three different damping characteristic curves (T50, T60, T70), and the damping characteristic curves for T50, T60 and T70 are shown in Fig. 11(a). The unloading force gradually increases and the unloading speed gradually decreases. Wheel wear of different damping characteristics is shown in Fig. 11(b), (c), (d), and (e), where the depth of wheel wear decreases as the damping characteristics increase. The wheel wear depths of three damping characteristics are 1.072 mm, 1.047 mm, and 0.99 mm, respectively, with an operation mileage of 200,000 km. The damping characteristics of the anti-yaw damper can effectively suppress wheel hollow wear. The evolution of wheel wear was calculated for different nodal stiffnesses (4 MN/m, 6 MN/m, and 8 MN/m) of the anti-yaw damper, as shown in Fig. 12. As the nodal stiffness increases, the wheel wear increases, and with the operation mileage of 200,000 km, the wheel wear depths at the three nodal stiffnesses are 0.979 mm, 1.06 mm, and 1.099 mm, respectively. This is mainly when the node stiffness increases and the vehicle stability is further improved, which leads to a further reduction in the amplitude of the wheel hunting motion and thus a further increase in wheel hollow wear.
RSFT-RBF-PSO: a railway wheel profile optimisation procedure and its application to a metro vehicle
Published in Vehicle System Dynamics, 2022
Yayun Qi, Huanyun Dai, Pingbo Wu, Feng Gan, Yunguang Ye
The MBS model of a B-type metro vehicle operating on a Beijing Metro line is established in this section. In the muti-rigid model, the vehicle includes four wheelsets, four axleboxes, two bogie frames, and one carbody. These rigid bodies are connected with the first and second suspensions. The suspensions consider three translation directions’ stiffness and damping. There is no yaw damper in this B-type vehicle. The axlebox considers one rotation movement (around -axis), the sleeper considers 3 degree of freedoms (DOFs), other rigid bodies consider 6 DOFs. Totally, the MBS model of the vehicle has 62 DOFs. The wheel-rail normal force is calculated by Hertzian contact [18] and the tangential force by FASTSIM [19]. The mass properties of the vehicle are listed in Table 1. The applied track irregularities are the AAR5 track spectrum. The rail profile used in the model is a profile widely used in China metro lines, named CHN60. The vehicle speed used in this work is 60 km/h. The friction coefficient between the wheel and the rail is set as 0.4. The final model of the B-type metro vehicle simulated in SIMPACK is shown in Figure 1(a). The adaptive solver SODASRT2 with a tolerance of 10−5 is chosen for the dynamic calculation.
On the problems of lateral force effects of railway vehicles in S-curves
Published in Vehicle System Dynamics, 2022
To compare the simulation results with the experimental (measured) data, a synchronisation of the relevant signals had to be done at first. For this purpose, the signals of the vertical acceleration on the first wheelset were used. In these signals, a transition of wheels 11 and 12 over both turnout frogs in the investigated track section is detectable (see graphs 1 and 2 in Figure 14). Subsequently, it is possible to compare the time behaviour of damper deformation of the instrumented yaw dampers (D2L and D2R) with relevant simulation results. The comparison is performed in graphs 3 and 4 in Figure 14. It is evident that the measurement and the multi-body simulation provide similar results from the point of view of their shape as well as the reached values. A smoother character of the simulation results is related to the fact that the simulation was performed on the track without irregularities. Besides to the yaw damper deformation, the difference between the deformation of the left and the right yaw damper was also evaluated. The yaw damper deformation difference is just the quantity which can be used for the on-board detection of curve radius. The results presented in graph 5 in Figure 14 show a good correspondence between the measurement and the simulation again.