Stuctural Strength Analysis Of Aluminum-alloy Trimaran

As a research hotspot in the field of new ship type in recent years, Trimaran has a broad application prospect in military and civilian aspects because of its special structure and excellent performance. To meet the requirement of lightweight and high performance,trimaran usually use aluminum-alloy as it's hull material, that's puts higher requirements on structure strength. Aluminum-alloy applied to the trimaran can reduce the hull strength. At the same time,the fatigue strength of aluminum-alloy is weak, that makes the aluminum-alloy trimaran's fatigue problem is more serious than ordinary steel mono-hull ship. To solve above problems,this article will combine load and structure characteristics of aluminum-alloy trimaran, explore suitable evaluation method for aluminum-alloy trimaran, the main research contents include:1) Summarize the content about structural strength assessment in the LR rules for trimaran, the main content include: the calculation of trimaran's load, the check of hull girder strength and Cross-deck strength, the analysis of the result.2) The direct calculation method of the structural strength of aluminum-alloy trimaran were studied. first of all, using the wave-design method calculate design load. Then, through the FEM calculate the aluminum-alloy trimaran's stress response. Finally,studying suitable strength assessment criterion for aluminum-alloy trimaran, then checking the yield and the buckling strength of the trimaran.3) The simplified method of study of the fatigue strength of aluminium-alloy trimaran were studied. Content mainly includes: Determining the position of fatigue assessment;Selecting the method of calculation of the fatigue load that suitable for trimaran; Calculating the hotspot stress; According to the result of fatigue test about aluminum-alloy, determining the S-N curve of aluminum alloy material. In the end, Calculating the cumulative fatigue damage and analyzing the result of fatigue assessment.4) Two kinds of direct calculation method of fatigue strength evaluation of aluminium-alloy trimaran is studied(wave-design method and spectral analysis method). First of all,Introducing the principle and process of two method. Later,the two methods were used to assess the fatigue strength of the aluminium-alloy trimaran. Finally, analyzing the assessment results of two methods.