The Study On Hull Strength Of Small Boat Of High Density Polyethylene

As the country's emphasis on environmental protection and sustainable development issues,the old hull,high energy consumption,heavy pollution of small ship is replaced schedule step by step.Because of construction and maintenance of existing problems,it become resistance in the process of glass fiber reinforced plastic to replace wooden ship,because of its special performance,high density polyethylene ships is gradually began to emerge..Dalian Blue Flag Ship Co.,Ltd.took the lead in building HDPE as hull construction material,had built a series of boats with high density polyethylene which used for farming and fishing.This paper takes high-density polyethylene open boat which build by Dalian blue flag shipping co.,LTD.To as the research object,using the finite element analysis was carried out on the open boat hull strength and modal analysis;After using the finite difference method to strengthen boat body to solve the modal sensitivity,find out the most sensitive hull plate for modal frequency component,modify its size parameters properly,and to validate the strength calculation.The method and the results for subsequent give some reference to design and manufacture of high density polyethylene ships.The main contents of this paper include:Firstly,testing the mechanical properties of high density polyethylene sheets,using the mechanical properties of high density polyethylene plate to statistical processing of data from finite element analysis and calculation for the follow-up to provide a more accurate material mechanics performance data,to make the results more close to the testing result performanceSecondly,established High density polyethylene open boat three-dimensional finite element model,using the finite element analysis on the hull strength and modal analysis.From the calculation result,the boat hull strength and rigidity is good,can meets the requirement.Finally optimizing the structure of the finite element model,use the limited difference method to optimize the model of hull modal sensitivity analysis,find out the most sensitive component of modal frequency and plank,modify Finite element model for the optimized corresponding parts of the plate thickness the modal analysis and strength calculationThrough the study of the paper,the conclusions were as follows:First the boat stress and deformation nephogram result is get by the finite element static analysis carried out on the open boat,the calculation result shows that the strength of the hull meet the requirements.Find structure stiffness weak spot from Hull modal cloud,to strengthen it,after finite element static analysis and calculation to get the corresponding stress and deformation cloud,found that the model maximum stress after strengthening lower than the original model.Second using local strengthening modal sensitivity analysis on the open boat to find out the most sensitive of modal frequency of hull plate,then to modify its size accordingly.The finite element static analysis,find out that the modified model of maximum stress than the original model has been greatly reduced,the hull modal frequency is increased greatly.It proved that this optimizing method is feasible.Through this study proved that the high density polyethylene open boat can meets the requirement.The method and the results for subsequent give some reference to design and manufacture of high density polyethylene ships.