Research On Dynamic Characteristics And Vibration Optimization Of The Large Caliber Naval Gun Launch System

With the development of national defense,the naval gun gradually are developing to a larger caliber,which puts forward higher requirements for the shooting accuracy and shooting stability of the large caliber naval gun.The excitation source of naval gun has the characteristics of high intensity and instantaneous impact,and the vibration and impact during launching will make the performance of naval gun weapon system worse,such as the reduction of shooting accuracy and shooting stability.Therefore,the problem in the design of the inherent quality characteristics of large-caliber naval gun equipment becomes the focus of the research on the launch system of naval gun.Aiming at the above problems to be solved,this paper firstly made a theoretical analysis of the launch system dynamic problem of large-caliber naval gun.According to the actual physical structure,the kinematics equations of the launch system are derived by taking the kinematics of typical components of the launch system as variables.On the basis of the kinematics equation,the dynamic equation of the system is derived by using the principle of virtual power.Secondly,considering the influence of shear deformation of beam section,the dynamic model of the flexible variable section beam is obtained based on the Timoshenko beam theory,and the rigid-flexible coupling dynamic model of the body tube is established.Then the rigid-flexible coupling dynamic equations of the whole gun with barrel flexibility and constraint relations are obtained by Timoshenko theoretical derivation.In this paper,the vibration theory analysis of typical components of large-caliber naval gun is carried out and its vibration characteristics are explored.The vibration numerical analysis method of structural beam is studied,and the simplified vibration theoretical model is established by simplifying the structure of the naval-gun rolling frame and bracket,the natural frequencies and modal shapes of typical components are calculated by numerical method.Then the vibration response of the shaking frame and the bracket is analyzed by applying the actual excitation load to the model and introducing generalized coordinates.The modal analysis of two typical components of naval gun launching system is carried out by using Ansys software,and the natural frequencies of the typical components and the corresponding modal modes of each natural frequency are obtained,which verifies the correctness of the theoretical vibration model.On the basis of theoretical analysis,the dynamic simulation of the launch system with contact collision is carried out.According to the simplification principle,the 3d solid model of a certain type of naval gun launch system is established,and the connection relation,contact problem and excitation load of each part are defined.Ansys was used to make the barrel flexible,and the rigid-flexible contact between the end of the barrel and the gun tail was explained.The rigid-flexible coupling simulation is carried out by using Adams to obtain the kinematics characteristics of the gun body of the naval gun launching system and the vibration in two directions of the muzzle position,and the contact force analysis is carried out for each contact position.Based on the dynamic simulation results of the launch system,the structural dynamic response of the muzzle vibration was optimized.Firstly,the parameterized finite element model of naval gun launch system was established,and the kriging approximation model was constructed by using the optimal Latin hypercube test design method.The NSGA-II algorithm was selected to optimize the constructed approximate model to obtain the Pareto front of the objective function.The sample points which improved the parameters of the test output response were selected in the Pareto solution set to realize the optimal matching of muzzle vibration.