Model Method Of Shock Environment In Ship Far-field Underwater Explosion

Based on far-field noncontact underwater explosion, there are some uncertain problemsin modeling the ship structure and external flow field. In order minimizing human error andimproving simulation precision, analysis the influence of different modeling andsimplification method in ship shock response, and put forward a set of standardizationmodeling method. This paper proceeds as follow.First, this paper summarize the method that described shock environment and ship shockresponse in underwater explosion, and then analyze the application scope of various methods.Secondly, establish simplified model of surface warship to simulate the shock responsebased on far-field underwater explosion. By changing the region、element size、element shapeand gradual rate of external flow field, analyze the low and high frequency response of thestructure and then summarize a set of standardization modeling in external flow field.Thirdly, establish the tanker model in detail which include bracket and cutout(man-hole、lightening hole) and make contrast analysis on shock response with the simplified model. Thepaper analyzes the effect of local structure simplification in shock environment from low andhigh frequency response, and effect of local structure simplification in stress wave attenuationfrom peak stress. Further, shock response regulation is gained based on numerical results.Fourthly, simulate the response of shipboard equipment in far-field noncontactunderwater explosion. Through plenty of numerical calculation, the paper discusses the effectof different equipment modeling method and simplified method in shock input. According theequipment quality and connection method of equipment, summary the modeling method ofshipboard equipment.Fifthly, it is excessively detailed to define beam direction through orientation key pointin the process of modeling ship three-dimensional finite element.This paper make a waycalled “far-point” method to simplify the definition method of beam element. Investigate theeffect of “far-point” method on structural stiffness and summarize the usage of “far-point”method.