Effect of rail pad stiffness on the wheel/rail force intensity in a railway slab track with short-wave irregularity

Abstract

In this paper, a two-dimensional numerical model is developed to investigate the effect of rail pad stiffness on the wheel/rail force in a slab track with harmonic irregularity. The model consists of a vehicle, nonlinear Hertz spring, rail, rail pad, concrete slab, resilient layer, concrete base, and subgrade. The rail is simulated using the Timoshenko beam element for considering the effects of high-frequency excitation produced by short-wave irregularity. The results obtained from the model are compared with those available in the literature and from the field to prove the validity of the model. Through a parametric study, the effect of variations in rail pad stiffness, vehicle speed, and harmonic irregularity on the wheel/rail force is investigated. For the slab track without any irregularity, the wheel/rail force is at maximum when the vehicle speed reaches the critical speed. As the rail pad stiffness increases, the critical speed increases. When the amplitude of irregularity is high, wheel jumping phenomenon may occur. In this situation, as the vehicle speed and rail pad stiffness are increased, the dynamic wheel/rail force is increased. In the low-frequency range, the wheel/rail force increases as the rail pad stiffness increases. In the high-frequency range, the wheel/rail force increases as the rail pad stiffness is decreased.

Development of train ride comfort prediction model for railway slab track system

“…By assembling the elements, the slab track matrices of mass ([ ]), damping ([ ]) and stiffness ([ ]) were derived. The governing differential equation of the motion was provided in Khajehdezfuly (2019). The vehicle was simulated as a wagon with ten DOFs (Mosayebi et al 2017).…”

“…Each wheel was characterized by a mass of . The mass matrix ([ ]), the damping matrix ([ ]) and the stiffness matrix ([ ]) of vehicle were defined by equations (2) to (4), respectively (Askarinejad and Dhanasekar 2016, Khajehdezfuly 2019, Mosayebi et al 2017, Sadeghi et al 2016b, 2019…”

“…where is the contact force between the wheel and the rail, ℎ stands for the wheel vertical displacement, is the rail vertical displacement of the wheel-rail contact point, stands for the rail irregularity and is the Hertz spring constant. The stiffness, mass and damping matrices of the whole model were derived by assembling the stiffness, mass and damping matrices of the sub-models (Askarinejad and Dhanasekar 2016, Khajehdezfuly 2019, Sadeghi et al 2016a, 2016b, Sadeghi et al 2019. The vehicle-slab track dynamic interaction equation was solved using Advanced Solution Algorithm (ASA) developed by Sadeghi et al (2016a).…”

“…Altogether, 12 types (cases) of slab tracks with various combinations of rail pads and resilient layers were considered (Table 4). They cover the possible conditions of track properties (Khajehdezfuly 2019, Lei and Wang, 2014, Lei and Zhang 2010, Sadeghi and Esmaeili, 2018. The vehicle characteristics were adopted from Chinese railway vehicle called CHR3 (Lei and Wang 2014, Lei and Zhang 2010, Sadeghi et al 2016b).…”

Numerical Analysis of Vibration Responses in High‐Speed Railways considering Mud Pumping Defect

“…At present, numerical simulation has become an efficient solution to study the dynamic effects of railways with the development of computer science [14,15]. Many studies have been conducted with the vehicle-slab track coupled model including the comparison of two-and threedimensional models [16], the comparison of two-layered and three-layered slab tracks [17], the comparison of linear and nonlinear Hertzian contact theory [18], and the dynamic effects under different irregularities [19][20][21]. Furthermore, many efficient algorithms have been put forward to solve the nonlinear vehicle-track interaction problem [22][23][24][25].…”