Fluid-Structure Coupling Response Of A Large Ship Hull Under Wave Slamming Loads Based On VOF Method

When a ship travels in rough seas,it will impact the sea water because of the large relative motions between the ship and the wave surface,this impulse loads with high pressure peaks called ‘slamming'.This slamming event is related to the nonlinear and transient characteristic of the free surface,and when dealing with this complex event,a powerful tool should be developed to handle the hydro-elastic analysis of marine structure and the fluid-structure coupling,so the slamming problem has always been one of the hot topics in the field of marine engineering research.Slamming can have a significant contribution to the structural loading and masty transient vibration,and in order to avoid the damage induced by the slamming event and enhance the safety of the ship structure,the slamming loads and the subsequent whipping response should be accounted in the design of the ship.This article is based on the high-tech ship project of the Ministry of Industry and Information Technology.Numerical simulations of the wave slamming problems were performed in an available Fluid Structure Interaction(FSI)tool.This tool used an interaction partitioned coupling scheme between CD-adapco's STAR-CCM+(STAR),a CFD solver involving the VOF method to track the free surface deformation,and Abaqus finite element structural solver.This available FSI tool is used to simulate the structural flexible response during the slamming impact phases.First,taking the simplified structure water entry as the research object,the experimental design and numerical simulation are carried out,and the validity of the numerical model is verified by comparing the two.Then,the slamming phenomena of the hull model in the experimental tank are simulated numerically,and compared with the vertical slamming loads in the literature to verify the validity of the numerical model which coupled wave slamming response.Last,a large oil ship navigates in rough seas is modeled to observed the complex response.The slamming phenomena of ship hull under different working conditions are analyzed.The slamming load characteristics and structural stress-strain distribution characteristics are analyzed,which provides a foundation for the analysis of coupled slamming response of ship structure.This dissertation is presented in the following structure:(1)The numerical methods consists of finite volume method?VOF model?finite element method and the structural rigid response method are given,especially the numerical simulations of the wave based on the VOF method and the co-simulation procedure of commercial codes STAR and Abaqus.Based on this,a numerical model for coupling response of hull structure under wave slamming load is established.The effect of regular wave,the flexible response of the ship model,the ship speed and the incident wave parameter are discussed.(2)A 2D wedges water entry experiments with varying deadrise angeles are designed and carried out,and the pressure distribution on the wedge are analyzed.Then,a numerical simulation is conducted using the FSI tool,and good agreement is found between the solution predicted in STAR and Abaqus and the experimental results.Last,the influence law of slamming load and structural deformation under different parameters is analyzed.(3)An experiment with an aluminum model in reference is used to validate the current FSI tool.Regular head waves are used to investigate the slamming impact,and the experiments were carried out for two occasions: zero speed case and forward speed cases.The total heave force is compared to validate the slamming load forecasting method.Then,the free surface morphology change,load distribution characteristics and slamming response of ship model structure under experimental conditions are analyzed,which provides a foundation for the design of slamming load of ship hull structure.(4)This chapter takes a large oil ship as the numerical model,and based on the established numerical simulation technique for the coupled response of structures in slamming scenarios,the finite element model is built and the prediction of the structure response due to the wave slamming is analyzed.The slamming load,slamming phenomenon and structural response of different speeds are compared and analyzed.The hull structural response characteristics are discussed in detail,including the hull motion characteristics and structural stress distribution.Study provide a foundation for dynamic coupled response analysis of large ships under wave slamming loads.