Research On Bow Flare Slamming Load Forecast Induced By Wave

Slamming is a phenomenon in which the ship's body impacted by waves violently in the process of navigation.Slamming pressure is affected by many factors,such as sea wave characteristics,ship navigation state,structural shape,structural elasticity,air layer,water compressibility,etc.When a wave hits the outer floating area of the bow,it will produce a considerable pulse pressure,and the surface area is large,and the slamming lasts for a long time,which has a greater impact on the strength of the local structure.Therefore,in order to carry out a reasonable safety assessment of the local hull structure,it is very important to accurately predict the slamming pressure that changes with time.On the other hand,with the development of large-scale and high-speed ships,and the wide application of high-performance ships(planing craft,hovercraft,catamarans,etc.),traditional slamming theories and specifications are no longer suitable for engineering practice.New technical methods are needed to study the slamming problem.This article first summarizes the current research status of ship wave slamming pressure at home and abroad;next understands and absorbs both the Lloyd's Register of Shipping rules and numerical simulation methods.Based on the computational fluid dynamics software STAR-CCM+,the ship hull under regular wave environment.The slamming pressure is numerically simulated;the influence of wave environment and navigation conditions on the size and distribution of wave slamming pressure is systematically studied.On this basis,a method of CFD(Computational Fluid Dynamics)numerical simulation combined with ANNS(Artificial Neural Networks,ANNS)for wave slamming pressure prediction is proposed.The specific research work is as follows:(1)This article first discusses the research on vertical water slamming of local structures;then summarizes and summarizes the current research status and research methods of wave slamming;points out the research hotspots and difficulties of wave slamming,and introduces the solutions to the above problems.CFD numerical simulation method;finally discussed the advantages and disadvantages of this method.(2)Introduced the ship slamming theory(two-dimensional effect,three-dimensional effect);using STAR-CCM+ to numerically simulate the cylinder entry experiment in the literature,and compare the results with the experimental values,verifying the reliability of the numerical simulation method in this paper;Finally,the three-dimensional numerical pool was subjected to wave-making test and waveform verification.The time history curve of waveform at the monitoring point was consistent with the theoretical waveform,indicating that the numerical pool was effective.(3)Taking the 3800PCTC(Pure Car and Truck Carrier)ship as the research object,based on STAR-CCM + overlapping grid and six degree of freedom rigid motion model,the effects of regular waves with different wave parameters(wave height,wave period,etc.)on the slamming pressure of bow floating waves are studied,the slamming load and its distribution law are obtained.(4)Based on CFD numerical simulation technology,the slamming pressure of 3800 PCTC ro-ro ship under various wave states and navigation states is simulated,and the slamming pressure of monitoring points in different wave environment and different navigation states(speed and heading)is obtained.Through the sensitivity analysis of dimensionless parameters,the relationship between slamming pressure and wave height,the change trend of wave period and wave steepness are obtained.(5)The strong nonlinearity,randomness of load,coupling effect of multi-parameters,finiteness of data collection,and the time-consuming of CFD numerical simulation of the bow wave slamming problem have taken into account,a fast prediction method of bow wave slamming pressure under regular waves is proposed by combining CFD numerical simulation with artificial neural network.To sum up,this paper forecasts the slamming pressure of the ship in different wave environment based on CFD numerical simulation method;on this basis,the method of combining CFD numerical simulation with artificial neural network model is proposed to predict the slamming pressure of flare out bow under wave conditions.This method has a certain guiding significance for the rapid evaluation of bow wave slamming pressure.