The Analysis Of Dynamic Responses And Safety Of Torpedo Structure Subjected To Underwater Explosive Shock Wave Load

With the development and upgrading of anti-torpedo weapons,the role of torpedo in naval warfare has been limited to a certain extent.Torpedo's unique function is reflected in its huge explosion power,high search accuracy and superiority in sailing depth,voyage and speed against submarines or large surface ships.In order to more effectively resist the attack of intercepting bombs and play the specific role of torpedoes,it is necessary to study the structural response of torpedoes under the shock wave load of underwater explosions.Compared with the ship structure,the torpedo structure has more uncertainty,and the current research on the dynamic plastic response of the torpedo is mostly limited to the plastic deformation damage of a single shell structure subjected to shock wave load,and the related research is still incomplete and cannot meet the requirements of comprehensive evaluation of torpedo safety in engineering practice.Therefore,mainly based on the numerical method,the law of structural response and safety evaluation of torpedo subjected to underwater explosion load in different segments and different structures are systematically studied in this paper.The main research contents include the following parts:Firstly,the basic theory of underwater explosion is briefly described,and the calculation accuracy of the acoustic-solid coupling method used in this paper is verified by a simple thin plate structure.From the comparison of center deflection and deformation condition,it is pointed out that the influence of material strain rate must be considered in numerical simulation.Secondly,the overall structure and function of torpedo are introduced in detail,and a simplified model of torpedo structure and the basis for selecting torpedo parameters are determined on this basis,which lays a model foundation for the study of torpedo dynamic response under explosion load.The concrete contents include the shape and size of the torpedo,the form of the ring ribs,the layout of the rudder and fins in the rear section of the torpedo,the simplified way of the propeller,the position of the bearing platform of the control equipment,and the basis for selecting the material parameters,etc.At the same time,the establishment method of the flow field model is given.Based on the above model,the plastic response of torpedo under underwater explosion load is studied in this paper.Firstly,aiming at the problem that the contact surface between the flow field and the propeller structure cannot be defined in the software,the explosion load on the propeller is applied through the pressure test data of the double-sided back water plate.Secondly,the failure mechanism of the main shell structure is introduced,and seven typical working conditions are determined,taking into account different detonation distances,different angles,single and double shots,simultaneous explosions or sequential explosions separately,etc.Then,the nonlinear finite element software ABAQUS was used to simulate the underwater explosion condition,and the response characteristics and damage laws of different torpedo segments(fuse segment battery segment and rear segment)and different structures(shell appendages and electronic equipments)were analyzed and summarized.Subsequently,the local structural stress and dynamic plastic response of the torpedo segment connection structure are analyzed separately through the axisymmetric model created by the solid element.At the same time,the problem of power failure caused by torpedo entering explosion bubble is discussed by theoretical derivation.At last,the paper summarizes the torpedo's failure mode and puts forward a method to divide the torpedo's damage level.On this basis,the safety radius of the torpedo is determined so as to realize the purpose of systematically evaluating the torpedo's safety and provide a reference for engineering practice.