Study On Reliabilityof Hcsr Ship’s Ultimate Strength Based On Nonlinear Hydroelastic Theroy

With the increasing of the ship’s main scale and speed,the impact of nonlinear factors such as slamming and sea going on the ship is increasing da y by day.The traditional rigidity theory is no longer applicable,so it is necessary to treat the ship as an elastic body for nonlinear analysis.Based on the hcsr,this paper studies and analyzes the ship’s ultimate strength verification,and proposes a kind of calculable method And the three-dimensional nonlinear hydroelastic method of convolution and slamming force is used to predict the wave load.The hcsr code value is used to calculate the reliability of the ship’s ultimate strength to verify the rat ionality of the hydroelastic method.The main research contents are as follows:1.Based on the newly revised hcsr,the ultimate strength of ship girder is studied and analyzed,including the ultimate bearing capacity of ship hull,the load of ship hull(vertical wave load,vertical still water bending moment)and the checking formula of ship girder.The bearing capacity of midship section of a bulk carrier is calculated by the theory of progressive damage method Yes.2.To study the influence of nonlinear hydroelastic theory on the ship’s external loads,especially the wave loads.By considering the nonlinear factors such as slamming on the waves,a three-dimensional nonlinear hydroelastic method is proposed,which can take into account the convolution and slamming forces.The calculated value of this method under regular waves is compared with the traditional linear wave load prediction method and the experimental value to verify the nonlinear factors on the waves The influence of wave load can not be ignor ed.Through the finite element modeling of a bulk carrier,the nonlinear design wave method is used to predict the long-term ship motion and wave load,and the hcsr value under the hcsr code is calculated at the same time.Through comparative analysis,it is proved that the nonlinear hydroelastic method is more effective.3.Based on the principle of mathematical analysis and probability statistics,comparing the commonly used reliability analysis methods,by simplifying the variable types of limit state equation,comparing the Monte Carlo method and the first-order second moment method,choosing the reliability analysis method which can be applied to the total longitudinal ultimate strength of ships.4.In order to verify the practicability of the wave load under the nonlinear hydroelastic method in the calculation of ship ultimate strength,the reliability of ship ultimate strength under the method is analyzed.Combined with probability statistics and reliability theory,the limit state equation of the ship ’s ultimate bearing capacity is established.The statistical eigenvalues of each random variable in the limit state equation are calculated.Based on the reliability theory,the reliability check analysis of the ultimate strength of the ship’s beam under t he nonlinear hydroelastic method is carried out,and the hcsr code value is compared,which provides a reference for the hcsr code on the prediction of wave load.