Structure Strength Assessment Of Warship Based On Nonlinear Design Wave Approach

Warships with high speed and complex structure navigate under the abominableconditions, and the design wave approach has been extensively used in the structural strengthassessment. However, slamming and other factors may bring about the non-linear shipmotions and wave loads obviously, which cause serious threat on hull structure. So thenonlinear design wave approach has been adopted to consider the nonlinear factors What’smore, the analysis of structural responses included quasi-static method and transient responseanalysis method, and the vessel is in the dynamic motion under different sea conditions. Inorder to reflect the dynamic effect, the structural response analysis is often advised to usetime domain dynamic manner. Therefore, based on the nonlinear design wave approach, shipstructural strength assessment has certain practical significance by using the transientresponse analysis method.The main contents of this paper are as follows:1. Firstly, based on the basic principle and process of nonlinear design wave approach,the basic parameters of waves and wave loads design value of the target vessels aredetermined under the cruising and extreme condition. Then the results are compared withlinear methods.2Then the nonlinear ship wave loads and pressure are calculated under differentconditions by the three-dimensional nonlinear hydroelastic method. Three different loadingcalculation of quasi-static method have been studied and and reflected the total intensityinfluence of slamming loads on vessels.3. To consider the nonlinear slamming load, the dynamic calculation method has beenimplemented. The nonlinear wave load calculation and method of applying have been studied.Finally, based on the modal transient response analysis method, the structural dynamicresponses are computed in the condition of the nonlinear wave loads.4. Finally, non-linear design wave approach and nonlinear loads applying methods havebeen applied in naval ship structural direct calculation, which provided more reliable resultsfor structural design of naval vessels.