The Slipstream In 400km/h High-speed Railway Tunnel And Its Influence On Aerodynamic Fatigue Of Catenary Support Device

Catenary support device,as an essential equipment of electrified railway,bears complex and diverse loads.In the high-speed railway of 350 km/h,some catenary support devices appear serious fatigue damage after less than 3 years of use.Slipstream is the main aerodynamic load of catenary support device.When the train speed increases to 400 km/h and the existing tunnel cross section is 100 m²,slipstream will significantly deteriorate and seriously affect the safety performance of catenary support device.Therefore,it is of great significance to study the influence of slipstream on catenary support device aerodynamic fatigue in 400 km/h high-speed railway tunnel.In this paper,the influence of flow field and train/tunnel parameters on slipstream in tunnel is investigated.The evolution and distribution of slipstream in tunnel are clarified.The transformation method of slipstream to standard wind load in tunnel is put forward.The structural strength and aerodynamic fatigue life of catenary support device under aerodynamic load are analyzed.The main results are as follows:（1）The influence of flow field and train/tunnel parameters on slipstream in tunnel and its evolution were investigated.When the compression wave is in the same direction as the train,the slipstream speed will increase;when it is in the opposite direction,the slipstream speed will decrease;when the expansion wave is on the contrary.There are two strong vortex structures in train wake,and the intensity increases alternately.The slipstream reaches the maximum in the middle of the tunnel,and the vertical and transverse distributions of the positive peak values gradually decrease with the increase of the distance from the train.When the transverse distance from the track center line exceeds 7.5m and the vertical height exceeds 6.0m,the positive peak values basically remain unchanged,and the negative peak values of the slipstream at different positions are basically the same.The slipstream in the tunnel increases with the increase of train marshaling length and train speed,and the tunnel length has little influence on the slipstream.（2）A method to convert the slipstream to standard wind load in tunnel is proposed.The wind vibration coefficient=1.56.The shape coefficient=1.42,and the standard wind load isω_k=1.56×1.42ω₀=2.22ω₀.The relationship between the maximum stress on different parts of catenary support device and train running speed is proportional to the power of 2.1.When the train passes through a 100 m²high-speed railway double-track tunnel at 400 km/h,stress concentration will occur at the connection position between the transverse wrist arm and catenary spreader and the limit locator,and the maximum stress is1.838×10⁸ Pa and 9.256×10⁷ Pa respectively,meeting the allowable stress requirements of the equipment.（3）The aerodynamic fatigue characteristics of catenary support device are analyzed.With the increase of train speed,the aerodynamic fatigue performance of catenary support device decreases significantly.When the train passes through 100 m² high-speed railway double-track tunnel at 400 km/h,the aerodynamic fatigue life of the limit positioner position is the shortest,and its aerodynamic fatigue life is 8.24 years.More attention should be paid to the influence of wind load on overhead catenary support device in the structural design of high-speed railway tunnel.82 Figures,17 Tables,102 References...