Statistical Energy Analysis of Subway Wheel/Track Noise

2013 ◽  
Vol 423-426 ◽  
pp. 1563-1566
Author(s):  
Xiao Feng Zhang ◽  
You Gang Xiao ◽  
Yu Shi ◽  
Wu Yang Zeng

Dividing wheel-track system of subway into a series of sub-systems, the statistical energy analysis (SEA) model of wheel/track system is established. The factors affecting the wheel/track noise, such as modal density, damping loss factors, coupling loss factors, are gotten by theoretical analysis combined with experiments. The calculated results show that the track noise is about 4.5 dB(A) higher than the wheel noise at 160 km/h, and the wheel noise is reduced by 2.8 dB(A) at 160 km/h and by 2.3 dB(A) at 90 km/h by attaching damped layer plates to the wheels, but the total reduction is only 0.9 dB(A) at 160 km/h and 0.4 dB(A) at 90 km/h, so the attempts to reduce the total noise should exert noise control measures on the track, not on the wheel.

Statistical energy analysis SEA formulates the dynamic response of a system in terms of power and energy variables. The SEA parameters include power inputs; damping loss factors; which control the power dissipated within the system; and coupling loss factors, which control the power transmitted between coupled subsystems. One of the great difficulties in using SEA is the calculation of these parameters. In this paper sea parameters are formulated using general mobility functions. Simplifications that result from averaging the parameters either over frequency or over an ensemble of dynamic systems are presented. These simplifications make it possible to apply SEA to very complex structural-acoustic systems.


2011 ◽  
Vol 130-134 ◽  
pp. 824-828
Author(s):  
Lin Ji ◽  
Zhen Yu Huang

A simple technique is introduced to estimate the inter-modal coupling relations of two Statistical Energy Analysis (SEA) subsystems connected via an arbitrary interface. Based on a subsystem modal approach, the dynamic stiffness matrix of a generic built-up system is derived analytically. The coupling stiffness terms between any pair of subsystem modes can then be determined in explicit expressions. Under the proper SEA conditions, e.g. each subsystem has a high modal density and the couplings between SEA subsystems are sufficiently weak, these inter-modal coupling stiffness expressions can be greatly simplified. The results can then be easily accommodated within the standard SEA modeling procedure to predict the SEA response of generic built-up systems in a simple manner. Theoretical applications are made to estimate the SEA coupling loss factors between two subsystems connected by two rigid points.


2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Lin Ji ◽  
Zhenyu Huang

In statistical energy analysis (SEA) modeling, it is desirable that the SEA coupling loss factors (CLFs) between two continuously connected subsystems can be estimated in a convenient way. A simple SEA modeling technique is recommended in that continuous coupling interfaces may be replaced by sets of discrete points, provided the points are spaced at an appropriate distance apart. Consequently, the simple CLF formulae derived from discretely-connected substructures can be applied for continuous coupling cases. Based on the numerical investigations on SEA modeling of two thin plates connected along a line, a point-spacing criterion is recommended by fitting the point- and line-connection data of the two plates. It shows that the point spacing depends on not only the wavelengths but also the wavelength ratio of the two coupled subsystems.


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