# A New Top-Mounted Shear-Hinge Structure Based on Modal Theory and Rubber-Pad Damping Theory
## 1 Introduction
Their dynamic analyses mainly involved analyses of natural frequency vibration patterns and harmonious responses. Dynamic and static tests were conducted on a certain section of the line fastener, and the results showed that the insertion depth of the elastic strip was inadequate, resulting in resonance between the wave and wear-excitation frequency and the natural frequency, leading to the fracture of the elastic strip. [PERSON] et al. [19] took high-speed rail fasteners as their research object and studied the relationship between wave wear, fastener dynamic characteristics, and fastener dynamic stress. They revealed the cause of fastener sling damage and designed a new damped sling to withstand high excitation frequencies and reduce the vibration peak. Through strength analysis and dynamic characteristics analysis, the authors proved that the new damped sling can effectively reduce the frequency response and cost. [PERSON] et al. [20] investigated the effect of rubber-pad stiffness on the dynamic characteristics of a bridge deck plate using a transfer function, established a bridge model that considers continuous mass distribution in all directions, and analyzed the results obtained without an isolation pad and with different rubber shear moduli. It was shown that the rubber pads could effectively reduce the vertical natural frequency of the deck plate, except for the fundamental frequency, but they had little effect on the horizontal natural frequency. Rubber-pad floating slabs are used extensively on subway lines [21; 22; 23; 24], which proves that rubber can effectively reduce the vibration of floating slabs. The lower the stiffness of the rubber pad under the slab, the lower the natural frequency of the floating slab. In summary, in this paper, we design a new rubber-pad shear-hinge structure based on modal theory and rubber-pad damping theory. The aim is to reduce the natural frequency of the top-mounted shear hinge to the vibration level of the excitation frequency of the floating slab's lower region, and at the same time, reduce the vibration amplitude of the region with a higher vibration level. The damaged area and damage rate of the TMSH structure during the operation are first determined using field survey results. Then, refined models of the existing TMSH and the new TMSH are established, and the ultimate load-carrying capacity of the two structures is verified by determining the SSFST and static equivalent train load. The dynamic characteristics of the two structures are studied, and the natural frequencies and vibration patterns of the TMSH in its assembled state are obtained based on preload modal theory. Frequency-response function analysis of the damaged parts of the TMSH found in the field survey reveals the causes of damage, and the natural frequencies and frequency-response function peaks of the two structures are compared and studied to prove the effectiveness of the new structure from a simulation point of view. The new structure is proven to be effective in lowering the TMSH's natural frequency, reducing the influence of floating-slab excitation and improving the TMSH's fatigue life from two perspectives.