Research On Local Damage Of Warship Structure Subjected To Contact Underwater Explosion

It is a complicated physical process of the interaction between ship structures and contactexplosion load, which involves three phase change of solid-liquid-gas. The local damagecharacteristics of structure have caused intentions as the contemporary guidance technology’ smature leads to the incremental possibility of the superstructure、bottom and shipboardunderwater attacked by anti-ship missile and torpedo. So based on simplification processingin this paper the local damage effect of large navy ships bearing the explosive loading isstudied by numerical method、theoretical derivation and empirical formula, which haveimportant significance for the improvement of the protective performance.Firstly, common weapons native and abroad have been summarized and analyzed, andtypical attack weapons have been chosen. Air antiknock strength of large navy shipssuperstructures under different working conditions have been carried out through numericalcalculation with the detailed design of superstructure in deepening scheme. The damage effectof the superstructures subjected to typical anti-ship weapons has been analyzed from theaspects such as the deform characteristics、failure mode、crevasse size and affected areaSecondly, based on theory study of the predecessor, the damage of multilayer frameworkunder the contact explosion load have been analyzed by the energy method throughsimplifying model and referring to the compacted phenomenon of underwater explosionexperiment. The effectiveness of calculation method in this paper have been verified througha series of work. With the petals cracking effect considered and the energy calculatingmethod corrected, breach size of structures at each floor is obtained and the whole absorbingenergy is discussed by comparing it with related experiment data.Furthermore, the underwater explosion of the damage mode and the shielding propertyof typical double-shell structures bearing load have been studied based on the verification ofthe fluid-solid coupling method’s effectiveness by free field and breach empirical formula,and the damage mode and characteristics of structures have been analyzed. Stress-strain’sresponse characteristics at typical location have been extracted, and energy absorptioncharacteristics and proportion of structures at each floor have been analyzed at the view ofenergy. All of these provide the reference of the design of ship shield. Then, the speed and length of bubbly jet acting on structures have been derived byempirical formula, and the accuracy of jet model have been verified through the study ofinteraction between bubbly jet and plate by numerical method. The deform characteristics ofcomplicated double-bottom structure under the bubble jet load have been analyzed and itsdamage characteristics of destroyed structure attacked by contact explosion loading andbubbly jet have been further considered, which provide a feasible method to study thecomplicated underwater explosion phenomenon.At last，based on the widely investigation of the style of protective structure betweenshells，the protective design analysis between shells has been carried out. In this paper antiunderwater-contact-blast ability of different protective styles as X、Y and I has beencalculated by numerical method. with the comparison of different protective structures’deformation damage effect and dynamic performance have been analyzed， and theperformance improvement through structure optimization have been estimated. Finally，thestructure style with excellent impact resistance and economic performance have been chosen.