Research On Characteristics Of Impact Environment Of SWATH Catamaran

SWATH catamaran has been gradually brought into navy equipment in every country since its first appearance in the 1980s in the U.S.Compared with monohull ship,SWATH catamaran-as a newly-developing warship-has the advantages of fast route speed,good stability and low resistance,which largely depend on the particularity of its structure,however,there're few data about the influences of the big change in the structure on the impact environment.Thus,it's necessary to analyze the characteristics of impact environment before the evaluation of vitality of vessel.To study the impact environment related to SWATH catamaran,the research contents are as follows:1)Numerical simulation is performed to study the effects of bubble pulsation load,computational duration,system damping and filter frequency on the impact environment of the navy vessel,and then the analyses of distribution characters of the impact environment along the hull transverse,longitudinal and vertical directions are made.According to the calculation results,the main load,the best computational duration,filter frequency and key damping parameters can be obtained.Meanwhile,based on the distribution characters along the three directions,weakness of the equipment in the impact environment can be found.2)In view of the physical significances of design shock spectrum in practical applications,a method for the translation from shock spectrum to design shock spectrum is put forward,and a series of parameters are set in the translation process,then a feasible translation parameter suitable for rigid mounting is confirmed through the comparison of the response between integrated equipment and non-integrated equipment.Finally,codes for the recognition process of the parameters are written for the data processing in the impact environment analysis at the time of rigid mounting.3)To eliminate the limits in the traditional shock factors of SWATH catamaran,attention is focused on a new shock factor in this paper,and two simplified mechanical models are put forward on the basis of the underwater structural features of SWATH catamaran.Shadow area of the simplified model from shock wave is calculated,which is compared with the practical shadow area of underwater structure,thus obtaining a simplified model instead of the complex construction.Next,approximate theoretical formula for the calculation of the shadow area enriches the expression for new shock factor,which applies to SWATH catamaran.Through the new shock factor expression,the limits caused by explosion location and explosive distance are expected to be eliminated just with the same impact factor,aiming to obtain fast calculation of new shock factor for engineering application.