| Railway wagon couplers are subject to accidental unhooking during operation,and the internal parts of the couplers may crack or even break due to fatigue damage,which poses a great threat to the safe operation of trains.Because the hook device belongs to the space gap mechanism,its dynamic characteristics have certain randomness and relatively poor observability,leading to the difficulty of accident recovery.To this end,this paper uses the Recur Dyn multi-body dynamics simulation platform to simulate and analyze the dynamic characteristics of the hook device,and to investigate the reliability and fatigue life prediction of the hook device under different impact effects.Firstly,in order to describe the specific conditions of the hook device at different life stages in actual operation,three types of virtual prototype models based on the original design parameters of the hook device,the overhaul-to-limit parameters and the failure of the anti-jump components are studied and constructed.The simulation results show that the hook device is more sensitive to vertical impact.Among the three models,the locking iron rise in the overhaul-to-limit prototype model was higher than the maximum displacement of the locking iron in the original design parameter model,which was less than 28 mm and did not reach the unlocking position.The maximum displacement of the locking iron for the failure model and the wear model were close to each other.By adding a simple harmonic vibration condition of the hook,the impact of the vibration shock on the reliability of the hook device under the sensitive direction was further tested.The simulation results showed that the design model with the locking iron displacement reaching the unlocking amount was in the shock condition with an oscillation amplitude of 1° and a frequency of 25 Hz,while the failure model was in the shock condition with a vibration amplitude of 91.8mm and a frequency of 10 Hz.Finally,for fatigue damage in the hook unit,a rigid-flexible coupling dynamics analysis was carried out on the hook tongue,which has the lowest design strength in the whole vehicle unit,and the dynamic stress cloud showed that the S-shaped surface of the hook tongue is a high stress area,which is the same as the actual situation.The fatigue life prediction analysis was carried out on the high stress damage prone area of the hook and the results showed a life of 2.2 years,which is consistent with the actual results of 2-3 years in the field.The above research results provide a theoretical reference for the further improvement of the hook design and application specification,and help to enhance the safety of the hook device operation. |
