A Plastic Hinge Dynamics Modeling And Collision Behavior Response Research Of High-speed Train

The evolution process of train collision behavior is very complex and changeable,and it is frequently accompanied by various forms of instability such as climbing,derailment,and overturning after derailment,resulting in significant casualties and property losses.Realvehicle collision testing is expensive,so numerical simulation research is essential.It is an important development trend for the train collision numerical simulation method to maximize solving efficiency while meeting engineering application accuracy requirements.The plastic hinge modeling method has a significant advantage in solving highly nonlinear structural collision problems quickly.Therefore,in this study,plastic hinge dynamics modeling and collision behavior response analysis of high-speed trains were systematically carried out at three levels of energy-absorbing structure,single vehicle and multi-vehicle coupling.The main research contents of this doctoral thesis are as follows:The basic idea of elastic-plastic zonal multi-body dynamics modeling for high-speed trains,as well as the basic principle and process of plastic hinge dynamics modeling for energy-absorbing structures,are proposed based on multi-body system dynamics theory.Using the typical energyabsorbing structures of trains as an example,the feasibility and accuracy of the proposed method are validated in terms of practical engineering applications.The plastic hinge dynamics modeling and parameter modification of the anti-climbing energy-absorbing structure are investigated.A multibody dynamics model of an anti-climbing energy-absorbing structure composed of a composite rotation-translate hinge and a nonlinear spring element is developed.Plastic hinge nonlinear stiffness characteristics are obtained and corrected using substructure finite element quasi-static simulation and the computer inverse method.Under the same conditions,the calculation accuracy of the modified plastic hinge dynamics model of the anti-climbing energy-absorbing structure meets the engineering error requirements,and the solving time is only 2.90% of that of the finite element model.The influence mechanism of vehicle collision behavior and the dynamics modeling of the head-car plastic hinge were investigated.The head-car plastic hinge dynamics model,which included the vehicle-track coupled multi-rigid body dynamics model and the vehicle-end energy absorption structure plastic hinge dynamics model,was built on the concept of elastic-plastic zoning modeling.The dynamics model’s accuracy is validated by comparison with the rigid-wall test and the finite element model,and its solving time is only 0.79% that of the finite element model under the same conditions.The mechanism of influence of energy absorption structure parameters,vehicle structure parameters,and suspension parameters on vehicle crash behavior response was thoroughly investigated,and the key influencing parameters were eliminated.The plastic hinges dynamics modeling of the two-car train was performed,and the main causes of the two-car train’s lateral buckling behavior were investigated.The vehicle connection structure was discretized into a multi-body dynamics model linked by a complex universal-translate hinge and nonlinear spring elements,and a two-car train plastic hinge dynamics model was built.The nonlinear mechanical properties of the gas-liquid buffer and the collapse tube were determined using the trolley collision test.The effect of the vehicle connection structure’s initial posture on coupling collision behavior and train marshalling response was investigated.It was found that the initial lateral deflection angle of the vehicle connection structure had a significant influence on the lateral deflection of adjacent train ends,which was the main cause of the lateral buckling behavior of trains.The computer inverse technique was used to get the initial posture of the collision test back.The safety assessment and test verification of the five-car train were performed prior to the crash test.The impact velocity,the impact platform force of the energy-absorbing structure,and the initial lateral deflection angle of the vehicle connection structure were chosen as risk factors in a five-car train plastic hinge dynamics model.For the risk analysis of the five-car train collision test,eight different types of ultimate working conditions were created.According to the safety evaluation results,the improvement measures are put forward,and the collision test of five train lines is carried out smoothly.Compared with the five-car train collision test and finite element model,it is proved that the five-car train plastic hinge dynamics model meets the engineering accuracy requirements,and the solving time is only 0.35% of that of the finite element model.There are 140 figures,35 tables and 185 reference literature in this doctoralthesis.