Research Of Reasonable Vertical Stiffness Of Elastic Separated Rail Fastening

The sensitivity of the dynamic index of the vertical stiffness under different fastening system is studied by establishing the vehicle-track coupling model using the software ANSYS/LY-DYNA. Therefore, the vibration displacement of the rail, the wheel weight reducing load rate, the vibration displacement of the wheel, the vibration acceleration, the wheel/rail vertical force, as well as the dynamic bending stress of the rail are calculated. Thus, we can get the most reasonable vertical stiffness of the fastening system.The sensitivity of the dynamic index of the vertical stiffness under different fastening system is studied by establishing the vehicle-track coupling model using the software ANSYS/LY-DYNA. Therefore, the vibration displacement of the rail, the wheel weight reducing load rate, the vibration displacement of the wheel, the vibration acceleration, the wheel/rail vertical force, as well as the dynamic bending stress of the rail are calculated. Thus, we can get the most reasonable vertical stiffness of the fastening system.The result shows that the reasonable vertical stiffness of the fastening system is about 30kN/mm.Namely,the reasonable vertical stiffness is ranged from 20kN/mm to 40kN/mm.However,more accurate and reasonable stiffness need a more accurate calculation parameters and should be verified by field test.The study shows that the higher force transmission rate and power flow are both occurred nearby 200Hz by analyzing the force transmission rate curve and power flow curve under different stiffness combination cases.Besides, changing the stiffness of the pad under the iron plate has little effect on the force transmission rate curve and power flow curve when the stiffness of rubber pad under the plate is constant.Thus,compared with the solution "hard on soft down",the solution "soft down hard on" can improve the vibration and reduce the noise effectively.Considering to keep the geometry of the track and the need to improve the effect of vibration damping and noise reduction,the stiffness about 50kN/mm for the rubber pad under the rail and 80kN/mm under the iron plate is suggested finally.