Papers by Keyword: Irregularity

Abstract: taking the rail spectrum of high-speed railways suggested by the China Academy of Railway Sciences for example. maked spectrum estimation of sample space using the equivalent method based on power spectrum in frequency range and obtains the power spectral density of rail irregularity through Matlab programming. Results show that the smaller the mean square value is, the smoother the rail is. For v=200km/h, the simulated peak values of rail irregularity are all smaller than 12mm; when the high-speed train travels at 350km/h, the sensitive wavelength that causes strong vibration of the body can reach 100m.

Abstract: Critical speeds are the important indicators when evaluating the dynamic performance of the rail vehicle. In this paper, the whole multi-body dynamic model of the rail vehicle was proposed based on the theory of multi-body dynamics in the software of Simpack. And the linear and nonlinear critical speeds of the whole rail vehicle inspirited by the track spectrum were simulated. This will provide a basis for analyzing on the whole rail vehicle.

Abstract: Kiewitt dome structure is commonly used in spatial structures, on which many researches have been carried out. However, few researches focus on irregular dome structure. The mechanical performance of an irregular Kiewitt dome structure, cut by two vertical planes from a semi-sphere dome structure to form two openings supported by beams for architectural gates, is studied. The analysis and comparison of the dome structures with the opening or not, as well as the parametric analysis of section of the supporting beam, are conducted by SAP2000. Finally, nonlinear analysis is done by ANSYS. The results show that the existence of openings decreases the integrity of the structure and the members near the opening need to be strengthened. The stiffness of the arch beam has great effects on the vibration characteristics, the axial force distribution of the members, and the buckling modes of the structure. Proper arch beam section is recommended to meet the requirement of the structure.

Abstract: A new technique is present in this paper that transforms the railway track irregularity power spectral density of left and right rails into the excitation power spectral density of wheelset of train, compared with the railway track irregularity spectrums of left and right rails which are not the direct inputs of simulation dynamic model of trail. A parameter model is chosen as the model of excitation spectrum and parameters fitting result shows that this model is suitable for the excitation spectrums of traversing, floating and head shaking, and the method present in this paper is effective.

Abstract: In a mechanical system that has periodically repeated subcomponents, premature failures or malfunctions often occur. Due to slight irregularities of parameters of periodic systems, maximal frequency responses of a few subcomponents become often significantly larger than those of other subcomponents. These phenomena, called frequency response localization, need to be comprehended for reliable designs of the periodic systems. In the present study, the effects of parameter distribution patterns on the frequency response localization are investigated. Probabilistic results of the frequency response localization characteristics with two distinct parameter distribution patterns are exhibited.