Simulation And Optimization Analysis On Structural Response Of High-speed Composite Craft With Slamming

Fiber reinforced composites is widely used in structural parts,such as hull,superstructure,propellers and offshore wind generator blades,etc.in shipbuilding and offshore industry because of its high specific stiffness and strength,low weight,anti-corrosion properties.Currently,the study on composites and its application in marine and offshore industry has become a hot topic.There will be large amplitude heave and pitch motions of ship in complex sea conditions.Under the effort of the motions,the hull bottom will enter and exits from water at a very high frequency,which will be prone to result in slamming.Composite hull uses elastic deformation and destruction to absorb energy under slamming load.Although there is no visible damage or deformation to the surface of ship structure,the internal structure has delamination and debonding.Research of composites vessels in structural response to accidental loads is necessary to ensure vessels safety in complex marine conditions.Smoothed particle hydrodynamic(SPH)method is an element-free methods(EFM),which takes particles as the basic numerical calculation elements.There is no fixed topology relation between numerical calculation elements,hence SPH method can effectively avoid large deformation and distortion of elements.Currently,SPH method is widely used in the fields of water-entry impact,liquid sloshing and high speed impact.The article first applies SPH method to composite ship slamming in order to probe into this complicated non-linear problem.Firstly.SPH method is presented to simulate the process of water entry impact and experimental results are shown to verify the effectiveness of using SPH method to simulate two-dimensional and three-dimensional structure slamming.The impact to calculation accuracy for slamming by different feature length of particles is discussed in this article.Secondly,the article studies the low velocity impact on composite laminated plates by using the macro-mechanical properties of the composites and Hashin damage criterion and analyzes the impact resistance performance of structures from different aspects,such as stacking-sequence of composite laminate plates,impact location of punches and structural form of the stiffened composite panel.Finally,based on SPH method and damage criterion of composites,the influence of different backbone,thickness of steel plates and section feature of aggregates on slamming resistance of composite craft is studied.This article proposes a structural optimization scheme based on study result and provide guidance to the design of composite high speed craft with strong slamming resistance.