Research on the influence of loading frequency, material elasticity, and geometric parameters on mechanical characteristics of the new mesh-type high damping rail pad for fastening system

Abstract

The dynamic stiffness (DS) curve of the rail pad (RP) is related to its damping performance. In a vibration period under the action of a sinusoidal load, the energy consumed by the damping force of the RP is equal to the energy generated by the applied load. The theoretical derivation found that the DS curve area of the RP is proportional to its damping ratio (DR) and loading frequency, and the accuracy of the theoretical derivation is verified by establishing a finite element model of the fastening system. The finite element calculation (FEC) found that the larger the loading frequency, the larger the DS curve area of the RP. The larger Young’s modulus of the RPs, the smaller the area of its DS curve. The prismatic rail pad (PRP) and mesh-type high damping rail pad (MTHDRP) are respectively assembled in the fastening system, and the static/dynamic stiffness (S/DS) curves of the two RPs are compared through the FEC, it is concluded that the MTHDRP has lower S/DS, and its linearity of the SS curve is better, indicating that the MTHDRP has better stability and stiffness retention. Meanwhile, the area of the DS curve of the MTHDRP is significantly larger than that of the GRP, indicating that it has better damping performance. The S/DS tests of the two RPs verified the accuracy of the FEC. Finally, taking the elasticity of the damping block (DB), the height of the DB, and the meshes numbers as the research variables, the law of their influence on the S/DS and DR of the MTHDRP is studied. It is concluded that by increasing the elasticity of the DB, the S/DS of the MTHDRP will increase, and the DR will decrease. The S/DS and DR of the MTHDRP will increase with the increase of the height of the DB. As the meshes numbers increase, both the S/DS and DR of the MTHDRP will decrease.