Research On Protective Characteristics Of Shipboard Structures And Equipment Subjected To Underwater Contact Explosion

The protective design has been an effective measure to enhance a large warship 's capacity of anti-shock.Especially,the battle field nowadays has been gradually transited from land to ocean,so the power of naval warfare also indicates the combat capability and the economic strength of a country.In addition,with the development of new weapons,the threat of ship structures is more and more serious.In this paper,the protective characteristics of warships subjected to underwater contact explosions are studied in the terms of structural forms,the material types and the integration between the warship and its equipment,which aims to provide some references for the warship design.Based on the foundation laid by the previous scholars,the current situations on the damage and protection of stiffened plates,ship structures and equipment have been reviewed.Then,the pressure of shockwaves in free field is simulated and compared with that from the Zamyshlyayev equation.Furthermore,the underwater contact explosions of a bare plate and a simple stiffened plate are simulated.The results are verified by experiment so as to prove the effectiveness of the present ALE method.In terms of structural forms,the mode of the ship compartment is firstly analyzed by the ABAQUS software to test the reasonability of the numerical model,then the whole process of underwater explosions is simulated with ALE ranging from the charge detonation to the propagation of shock waves and the pulsing of bubbles.What's more,regarding the typical and latest design for the large warship,two types of the broadside structures,i.e.the wave type plate and the arc plate are established and the responses of the above two types of structures are considered from the views of damaged hole size,the area of the plastic zone and the energy absorption.Finally,the improved design is made to promote the protection capacity.In terms of the material selection,the composite laminated plate is taken as an example.Firstly,the simulations of a spherical and a cylindrical punch respectively impact on a sandwich composite plate and a conventional composite plate is carried out to test the constitutive relation provided by LS-DYNA.Then the sandwich composite plate is applied in the main longitudinal bulkhead to replace the common steel plate and the protective effectsare enhanced.Finally,the characteristics of the carbon fiber laminated plate under different layer modes are examined and the excellent one of[0,45,-45,X]x is found.In terms of the integration of ship and machine,the damage mechanism of the integration subjected to different explosion loads is conducted.On this basis,the shock environment is designated to reduce from the two aspects of new energy material and the shock absorber.The above studies aim to improve the protective performance and enhance the anti-shock ability.