Vibration Mitigation Effect Investigation of a New Slab Track Plate Design

Abstract

This study proposed a novel vibration mitigation slab track plate design to mitigate the vibration induced in urban rail transit operations. The optimal recipe for the newly designed slab track plate is obtained by a series of laboratory tests, and both newly designed vibration mitigation slab track plates and normal slab track plates are fabricated and hereinafter tested. The newly designed slab track plate was examined with a series of laboratory tests in comparison with the normal slab track plate. The PolyMAX method is then adopted for extracting the modal properties, including resonant frequencies, and damping ratios are also determined for both the designed slab and normal slab track plates. A vibration mitigation level (Ls) is defined to address the vibration mitigation performance taking the acceleration response of the normal slab track plate as reference. The newly designed slab track plate demonstrated better dynamic and damping characteristics in comparison with the normal slab track plate. Under the same excitation force, the newly designed slab track plate can mitigate 8.9 dB on average in the frequency range [20, 400] Hz, expressing the feasibility of effective vibration mitigation capacity.

Insights into the Effect of WJ-7 Fastener Rubber Pad to Vehicle-Rail-Viaduct Coupled Dynamics

“…Figure 8 shows the wheel-rail contact forces under five scenarios. From Figure 8, it can be found that: (1) below 20 Hz, the temperature dependent Young's modulus of the fastener rubber pad of the fastener had little effect to the wheel-rail force; (2) in frequency range [20,42] Hz, the amplitude of the wheel-rail force increased sharply as the temperature increased; (3) as the temperature increased, the peaks of the wheel-rail forces for all five scenarios decreased, and so did the dominant frequencies; the dominant frequencies for five scenarios were 74, 51, 47, 43 and 42 Hz, respectively; (4) In frequency range [56, 100] Hz, as the temperature decreases, the wheel-rail forces increased. Figure 9, for all five scenarios, the vertical accelerations of the vehicle had little difference, which suggests that the temperature dependent Young's modulus of the fastener rubber pad had little influence to the vertical responses of the vehicle on such occasion.…”

“…With the available Young's modulus, the stiffness of the structure can be obtained with Equation (20) and is shown in Figure 6b, the complex stiffness can also be determined with Equation (21) and is demonstrated in Figure 6c (absolute values). (20) where kf indicates the stiffness of the fastener rubber pad, Kf means the complex stiffness of the fastener rubber pad, A and h represent the section area, and thickness of the fastener rubber pad, respectively. (a) The temperature dependent Young's modulus of the fastener rubber pad is shown in Figure 6a.…”

“…This study takes the high-speed train CRH380A as example, the parameters are illustrated in Table 2, and the structural parameters for the viaduct are illustrated in Table 3. With the available Young's modulus, the stiffness of the structure can be obtained with Equation (20) and is shown in Figure 6b, the complex stiffness can also be determined with Equation (21) and is demonstrated in Figure 6c (absolute values).…”

“…Ahmad et al [9] studied the temperature-dependent stiffness of the rubber in the dynamic vibration absorber; Zhao et al [10] conducted temperature sweep tests for rubber, and analyzed the temperature-dependent stiffness of rubber material; Wei et al [11][12][13] investigated temperature-dependent stiffness of the fasteners in the subway system, and studied the nonlinear behavior of the temperature dependent stiffness of the fasteners; Liu [14] conducted temperature sweep tests for the fastener rubber pad, and found that at low temperatures, the fastener rubber pad shows low temperature sensitive performance, which further affects the vibration responses of the coupled system. As mentioned above, although certain investigations have been done for the fastener rubber pad-a kind of viscoelastic damping material [15][16][17][18][19], not too many studies can be found for the temperature dependent effect of the fastener rubber pad to the dynamic responses of the HSR system [16][17][18][19][20][21]. For instance, the effect of the rail fastener on the railway vehicle interior noise is investigated in [16], in order to study the temperature dependent stiffness of the fastener rubber pad, which further affects the dynamic responses of the vehicle-rail-viaduct coupling system.…”

“…This study takes the WJ-7B small resistance fastener rubber pad as objective, and Dynamic Mechanical Analysis (DMA) is applied for temperature sweep tests in order to obtain the mechanical properties of the WJ-7B small resistance fastener rubber pad; the dynamic flexibility method is then applied to construct the vehicle-rail-viaduct coupling model, by incorporating with the measured mechanical properties, the dynamic responses for each subsystem including the vehicle, rail, and As mentioned above, although certain investigations have been done for the fastener rubber pad-a kind of viscoelastic damping material [15][16][17][18][19], not too many studies can be found for the temperature dependent effect of the fastener rubber pad to the dynamic responses of the HSR system [16][17][18][19][20][21]. For instance, the effect of the rail fastener on the railway vehicle interior noise is investigated in [16], in order to study the temperature dependent stiffness of the fastener rubber pad, which further affects the dynamic responses of the vehicle-rail-viaduct coupling system.…”