As a component of servicing car body, the internal interfaces of aluminum alloy carbody include all connections of equipments hanged under floor and mounted on roof, which are expected to form the weak coupling relationship. For an imported prototype with primary hunting phenomenon, a dynamical design methodology of speeding-up bogies was proposed. The analysis graph of full-vehicle stability properties and variation patterns is used to clarify a self-adaptive improvement direction, i.e., λeN ≥ λemin, and λemin = (0.03–0.05). Therefore, the central hollow tread wear can be self-cleaned in time or regularly by crossing over the dedicated lines of different speed-grades. The modified strategy with strong/weak internal interface transaction of servicing car body was furthermore formulated based on the dynamical condensation method of component interface displacements. The causal relationship between bogie vibration alarm and car body fluttering phenomenon was then demonstrated by using techniques of rigid-flex coupling simulation. The self-excited vibration of traction converter intersects with the unstable hunting oscillation, ca. 9.2/9.3 Hz, which is consistent with the conclusions of tracking-test investigations on two car body fluttering formations. The technical space to promote the construction speed is thereby lost completely because of ride comfort decline, unsafe vibration of onboard electrical equipments, and weld fatigue damage of aluminum alloy car body. However, the rigid-flex coupling simulation analyses of trailer TC02/07 confirm that the safety threshold of bogie vibration warning can be appropriately increased as long as the lateral modal frequency of traction converters is greater than 12 Hz, preferably close to 14 Hz.
HSRS is taken as a typical research case of large-scale complex nonlinear systems, and the re-innovation of associated imported technologies needs to be combined with the particularities of Chinese HSR practices, seeking a more suitable dynamic design methodology to conduct the self-adaptive improved design. Different from the troublesomeness of the primary hunting phenomenon, the self-adaptive improved design can decrease considerably the impact of car body instability on ride comfort merely by applying the semiactive damping technique between intervehicles, to promote scientifically the limit and construction speeds under the rational conditions of wheel-rail matching, i.e., λeN ≥ λemin, λemin = (0.03–0.05). The researching viewpoint of hunting kinematics makes the investigations on the geometric nonlinearity of the wheel-rail contacts contrary to the hypothesis of small creepage and no spin. Since the technical prototype of German ICE3 serial bogies has the design default of the primary hunting phenomenon, the improved design of the wheel-rail relationship has simply abandoned the high-quality technical resources of wheel-rail matching conditions at low conicity. On the contrary, the dynamic simulation analyses of MC01-TC02-MC03 three-vehicles trainset show that the semiactive damping technique between intervehicles takes advantage of Izz >> Ixx to improve the impacts of car body instability on ride comfort, and the self-adaptive improved design has consequently the ability to achieve the technical goal of uniform wear at low conicity. On the premise of meeting the requirements of crossing over different speed grade dedicated lines and realizing the running operations on three-speed levels of 160/250/350 km/h, the self-adaptive higher-/high-speed bogies can conditionally satisfy the economic reprofiling requirements of wheelsets through the optimal routing planning.
For hi-tech manufacturing industries, developing large-scale complex nonlinear dynamic system must be taken as one of basic works, formulating problems to be solved, steering system design to a more preferable direction, and making correct strategic decisions. By using effective tools of big data mining, Dynamic Design Methodology was proposed to establish technical platform of Multidiscipline Design Optimization such as High Speed Rolling Stock, including three key technologies: i) Analysis graph of full-vehicle stability properties and variation patterns, providing instructive guidance on optimal parameter configuration of self-adaptive improved design for higher speed bogies to reduce track force; ii) Improved transaction strategy of flexible body to MBS interface, making boundary loading treatments more subtle to implement weak coupling interface of aluminium alloy car body to equipment cabin under floor frame; iii) Seamless collaboration with weldline fatigue damage assessments, ensuring structure integrity via correct Modal Stress Recovery. Steel rail profession unilaterally initiated improved design of wheel-rail relationship, which is proved to be unfavourable to commercial applications for Chinese High Speed Rails. On first fluttering phenomenon of service car body, contrastive analyses of line tracking tests and rigid-flex coupling simulations show that internal lateral coupling resonance of such as traction converter has been one of main restrictive factors that determine cost effectiveness. Whilst self-adaptive improved solution is one of more favourable options. Comprehensive evaluations show that only under rational conditions of wheel-rail matching, i.e. 0.10 ≥ λeN > λemin and λemin= (0.03–0.06), can this low cast solution achieve three goals of low track conicity, optimal route planning and investment benefit maximization.
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