Overall Design And Structural Strength Assessment Of Trailer Suction Dredger

At present,engineering ships used for underwater dredging in our country are mainly cutter suctic dredger,drag suction dredger,floating grab dredger,chain-bucket dredger,etc.Drag suction dredger is flexible,have strong ability to resist wind and high working efficiency,can be used to dig hard soil and soft soil underwater.Because drag suction dredger can operate in single and needs less auxiliary equipments.It can dredge in the process of sailing and have small impact on surrounding sailing ships,so it is one of our world's most advanced and highest-tech vessel in current.The method to combine afore suction dredging and drag suction dredging together is benefitial to work in different bed material,different waterways widths and different depth environments respectively,makes maximize use of equipments and saves one-time investments.However,the slot in forward part of drag suction dredger is used to place dredging equipments and has a very negative impact on overall strength of the hull.Based on the project of self-propelled trailer suction dredger in water transport planning and design institute of Heilongjiang province,the paper introduces rationality and necessary of the project in the aspect of channel status quo,ship selection and main parameters.After considering several factors,the design which sucker was placed in the front of ship,hull form type of wide draft and the function of self-propelled trailing suction hopper were choosed.And provides a set of design plan which meets design acquirement at the same moment.Then,the MSC.Patran/Nastran software is used to build the hull of the finite element model,and wave pressure under various conditions is calculated by SESAM.Besides,the yield and buckling strength assessment of the hull is completed,and we need to focus attention on stress distribution of the slot in forward part of trailer suction dredger under influence of waves in different directions.In this process,a set of buckling strength assessment program is developed according to CCS rules,and the results are fully consistent with CCS official plugin calculation software-CCS Tool,so the program makes preparation for developing buckling strength program of other major classification societies in the future.According to calculation results,the hull design meets the specifications of yield and buckling strength.Firstly,the yield stress results in opening on the deck and forhead of ship are dangerous,this needs our extra attention.Secondly,deck hull,bottom and aspect bulkhead plate are easy to fail in buckling assessment.More attention are need to pay on the first portion of the notch of vertical and horizontal bulkhead plate stiffened panels,the buckling results of the location is more dangerous in the each wave conditions.Finally,because of corner deck openings,fatigue damage are particularly noticeable at 180 degrees and 30 degrees nearly by studying spectral fatigue analysis of deck openings.