Investigation on Safety Assessment of Ship Launching with Airbags
REN Hui-long,LI Chen-feng,CHEN Zhan-yang(College of Shipbuilding Engineering,Harbin Engineering University,Harbin 150001,China)
Launching based on airbags is new technology of ship launching.However,there is no feasible method for quantitative assessment of the strength of hull girder and safety of airbags during launching process.With increase in light weight of ships,the risk of launching becomes more severe.With the nonlinear rigidity of air-bags and forces equilibrium condition of hull girder being considered during launching,a method based on entire hull FEA is put forward to assess the strength of ship structure and the safety of airbags in this paper.The main contents are as follows.(1) Considering nonlinear rigidity of airbags,a calculation method of rigidity of airbags is studied.(2) A method of calculating ship motion and forces on ship hull is studied with the nonlinear rigidity of elastic foundation being considered.(3) The stress of hull structure and the forces on airbags are calculated by entire hull FEA.(4) Comparison with common assessment methods shows that the safety of ship launching by airbags is estimated better and that the reliability of the calculation method presented in this paper are verified.