A 3D coupled Timoshenko beam-thin plate model with Green’s functions framework for broadband vibroacoustic analysis of steel-spring floating slab tracks

Abstract

Although steel-spring floating slab tracks (SSFSTs) effectively suppress mid-to-low frequency vibrations, their performance is constrained by inadequate noise control, component vulnerability and limitations of conventional models in broadband response prediction. This study develops an innovative model integrating a three-dimensional (3D) double-rail coupled Timoshenko beam-thin plate theory with a Green’s functions framework. This approach establishes a complete track model under asymmetric wheel-rail excitation, eliminating conventional symmetry assumptions. Specifically, an analytical Green’s functions framework for the floating slab is constructed using modal superposition and bidirectional beam function, enabling efficient calculation of broadband vibration responses from 0 to 4000 Hz. Subsequently, vibration data computed via the Fourier transform are employed within a 2.5D boundary element method to quantify track sound radiation characteristics. The model’s validity is demonstrated experimentally using hammer impact tests and wayside noise measurements. The results indicate that traditional simplified single-rail models yield non-negligible errors under asymmetric excitation. Furthermore, the proposed 3D coupled Timoshenko beam-thin plate method more accurately characterizes the low-frequency vibration coupling between rails and the floating slab, as well as wheel-rail noise generation. Notably, the double-rail model achieves significantly higher accuracy in the 0–300 Hz range than its single-rail counterpart, preventing underestimation of coupled vibrations. A parametric analysis revealed that reducing the isolator stiffness to 5–6 kN/mm significantly attenuates the floating slab noise in the 1–10 Hz and 70–134 Hz bands but amplifies rail (20–70 Hz) and floating slab noise radiation (134–180 Hz). Additionally, non-uniform isolator arrangements reduce responses and induce anti-resonance effects between 8 Hz and 50 Hz. The proposed approach provides a precision model for predicting broadband vibroacoustic behavior of SSFSTs, revealing nonlinear relationships between isolator parameters and vibration energy transfer paths.