Investigations On Anti-Explosion And Anti-Shock Performance Of Large Surface Warships

In modern naval warfare,the ship has become the major combat platform,and its antiknock performance research is increasingly concerned by naval powers.The manufacturing technology of modern ships and weapons systems are complex and costly.If can't meet the requirements,not only affects the full play of operational performance but also brings huge economic losses.The underwater explosion of real ship is the most direct way to assess the ship's antiknock ability,but the experiments of real ship need to spend a lot of funds,so the difficulty of test is relatively large.Therefore,it is important to carry out the method study on impact assessments of local and overall strength for different functional ships.This has a great significance in establishing the assessment system and enhancing the design level of ship structures.A lot of work has been done on the underwater explosion shock loads,shock response of ship structure and equipment,and a number of simulation methods have been proposed in our country.But in improving the performance and impact of ship antiknock vitality,the various naval powers in Europe and America have invested a lot of manpower and resources to conduct research.Many explosion experiments of real ship have been conducted and a lot of valuable environment data of local intensity and shock environment is accumulated.Moreover,China's underwater explosion experiments carried out relatively small,to a certain extent,it limits the enhancement of design capabilities of ships in explosion and shock resistance.In the research of ship survivability,foreign countries have special numerical simulation software of underwater explosion,and this professional simulation software is embargoed on China.Therefore it requires an independent study of underwater explosion simulation field.Since there is still a gap for China in impact research areas of ship and shipboard equipment compared to other naval powers,it is particularly important to compare different types of ship and carry out studies on impact strength and shock environment of hull structure subjected to underwater explosion.According to China's naval combat power to choose two types of ships: the auxiliary ship and the surface combat ship.The auxiliary ship main task is to transport supplies and the surface combat ship is the main fighting force during combat.The functions of two kinds of ships are different.But because they are military vessels,their strength and shock environment should have a more stringent requirement than normal vessels.In the past research of ship shock resistance,there is little to analyze the impact strength and shock environment for specific function of ship,and the contrast of strength and shock environment for different functions of ships is even scarcer.Based on the study situation of anti-explosion and anti-shock performance of ships at home and abroad,a series of numerical simulation analysis on strength and shock environment of our auxiliary ship and the surface combat ship subjected to blast loadings were carried out,and structural strength and shock environment of two ships were compared.Setting a series of different conditions including far field,near field and contact underwater explosion,the shock response,damage,local strength,overall strength,residual strength and shock environment of the auxiliary ship and the surface combat ship were analyzed and studied.It aimed at making a comprehensive analysis on aspect of impact strength for our main combat force and logistical support force,which can provide a reference for the research of ship survivability and structural design of hulls.This paper first started with the main dimensions and other parameters of the auxiliary ship and the surface combat ship,combining the longitudinal strength specification of CCS(China Classification Society),GJB4000-2000 and check criteria of LR(Lloyd's Register of Shipping),a calculation criterion of overall strength assessment for two ships was proposed.It described the theoretical analysis process of the ship's shock environment,which established a theoretical basis for analysis of the shock environment of the auxiliary ship and the surface combat ship under explosion.In accordance with the drawings of the auxiliary ship and the surface combat ship,the three-dimensional finite element models of two ships were established.According to the set conditions of underwater non-contact explosion,the impact response of two ships was numerical simulated and forecasted,and the longitudinal strength was studied.The validity of computing method for ship structural strength subjected to underwater contact explosion is verified by underwater near-field explosion test of real scale hull partial plate frame structure.Then setting different conditions,the local damage of the auxiliary ship and the surface combat ship subjected to underwater contact explosion was analyzed.A checking criteria and computing method of residual strength under contact explosions was put forward,and the residual strength of two ships was checked and analyzed comparatively.The numerical simulation method was applied to calculate the structural strength of the auxiliary ship and the surface combat ship under different conditions of air explosion,and the crevasse and plastic zone was analyzed.Meanwhile,applying the LR military regulations,the residual strength of two ships under air explosion was checked.And the local strength of two ships was compared.Finally,the impulse response of the auxiliary ship and the surface combat ship subjected to underwater far field,near field and cabin explosion was calculated.The shock environment of two ships under the explosion at stem,midship and stern was carried out a series of calculations and analysis,and shock environment of the auxiliary ship and the surface combat ship was compared.At the same time,the distribution rule of shock environment along the length of ship and the vertical direction was studied.In conclusion,in this paper,the overall strength,the local strength,the residual strength after damage of the explosion and the shock environment of the auxiliary ship and the typical surface combat ship were carried out a series of research and analysis,including the conditions of underwater far field,near field and cabin explosion which were the likely to be attacked.The analysis results can give a reference for the assessment of the ship's own strength and shock environment.According to the calculation model of the auxiliary ship and the typical surface combat ship herein,the research achievements can also provide guidance for the design of other types of military vessels.