Research On Deformation And Damage Of Welded Steel Plate Under Underwater Explosion

In order to further improve the underwater anti-explosion and impact resistance of the ship.Based on the near-field underwater explosion load damage ship welding plate structure,this paper aims to illustrate the plastic dynamic response and impact damage characteristics of welded plates under multiple near-field underwater explosion loads.It not only provides reference for the establishment of damage assessment and protection design methods for surface ships,but also has important engineering guiding value and strategic significance.Based on the theory of plastic deformation strain field of plates under blast loading,the method of numerical simulation and experiment is used to study the deformation and failure of steel plates and welded plates under multiple near-field underwater explosion loads.Firstly,this thesis summarizes the research status of near-field underwater explosion load and its dynamic response to marine steel plates and welded plates.Aiming at the dynamic plastic deformation and impact damage of marine steel plates and welded plates under multiple near-field underwater explosion loads,the quasi-static and dynamic mechanical properties of a typical marine welded steel plate,weld and heat affected zone materials were tested.The static and dynamic mechanical properties of the three materials were obtained,and the Johnson-Cook constitutive model of each part of the typical marine welded steel plate was fitted according to the mechanical property test results.Then,the underwater explosion finite element model of welded plates is established by Autodyn,and the numerical simulation of the dynamic response of welded plates and steel plates under near-field underwater explosion loads is implemented.According to the simulation results,the near-field underwater explosion loads and test plates are analyzed.The fluid-solid coupling mechanism is used to obtain the impact response law of marine welded plates and steel plates.The dynamic plastic deformation laws of near-field underwater explosion loads are analyzed from the aspects of velocity,deflection and thickness reduction of welded plates and steel plates.Finally,based on the underwater explosion bulging test,the impact damage characteristics of welded plates and steel plates under multiple near-field underwater explosion loads are studied.The plastic deformation of welded plates and steel plates under multiple near-field underwater explosion loads is obtained by analyzing the test results.The impact damage characteristics of welded plates and steel plates under multiple near-field underwater explosion loads are analyzed from the aspects of deflection,strain and thickness reduction.On this basis,based on the tensile strain hypothesis,the failure mode of the welded plate and the steel plate under multiple near-field underwater explosion loads is analyzed,and the dynamic fracture ultimate strain of the welded plate is obtained.