Equivalent Static Method For Slamming Responses Of Local Structure Of Trimaran

In recent years,due to the maturity of shipbuilding technology,high-performance new ships are increasingly concerned by scholars.Trimaran has always been a research hotspot because of its unique ship type,excellent dynamic performance and excellent combat environment.However,the unique structural characteristics of trimaran bring the advantages of low wave making resistance and high lateral stability.At the same time,the traditional research results of trimaran can’t reflect the real slamming characteristics of trimaran due to the influence of sheet and cross-deck.Therefore,the dynamic response of trimaran cross-deck under slamming load is further studied in this paper.Firstly,according to the basic theory of relative motion prediction between ship and wave,combined with the hydrodynamic grid of trimaran model,the ship motion responses calculated by three-dimensional linear frequency domain method and threedimensional nonlinear time domain method are compared and analyzed,and then a calculation method which is more in line with the principle of engineering safety design is selected.Secondly,a simplified model with similar internal component arrangement and external shape to the trimaran cross-deck is introduced to analyze the transient response of the simplified model under the wave slamming load,and the dynamic response results calculated by direct integration method and modal superposition method are compared and analyzed.In addition,the influence of damping,modal number and other parameters on the calculation accuracy is discussed,and a more efficient and accurate method is selected for dynamic response analysis.Based on this calculation method,the influence of different shape parameters of slamming load on dynamic response is studied.Thirdly,the equivalent static coefficient is introduced to analyze the dynamic response of the structure in the slamming problem,and the relationship between the dynamic response and the static response of the grillage structure under the slamming load is established The influence of transverse separation moment and material nonlinearity on the equivalent static coefficient of grillage structure is analyzed,and the variation law of the equivalent static coefficient with the duration is summarized.The feasibility of using equivalent static method to calculate deformation under slamming load is discussed.Finally,the static response of the trimaran segment model is calculated and analyzed,and the dynamic analysis of the structure is realized through the equivalent static coefficient,and the yield strength under the three equivalent static coefficients is compared and analyzed,and then the applicability of the three equivalent static coefficient calculation methods is discussed.