Design And Strength Analysis Of Movable Ship Launching Support System

Mobile ship launching means that the ship will be built on the horizontal berth,which will be transported to the floating dock by the module car,and then the floating dock will complete the launching operation.In recent years,shipyards have made full use of existing resources to seek ways to improve efficiency.At the same time,this launching method has emerged as the times require,which can reduce unnecessary resource occupation for shipyards.The mobile ship launching method is to move the ship through the support system.Therefore,the support system is the guarantee for the safe launching of the ship.In order to ensure the safety of the ship and enable it to be launched smoothly,it is necessary to carry out the design and strength analysis of the mobile ship launching support system.In this thesis,the support system of a car carrier launching is taken as the research object.The main research contents are as follows :(1)Read and sort out the domestic and foreign literatures related to ship launching methods,cushion wood material properties and support structures in recent years.This thesis introduces the mobile ship launching process,expounds the equipment selection and preparation matters of the process,analyzes the launching process,and summarizes the main risk points of the launching process.(2)The moisture content test of the marine padding wood in the launching support system was carried out,and the mechanical constitutive relationship of the test material was obtained.The elastic modulus,strength and other performance parameters of the padding wood under different moisture contents were obtained.Based on the finite element software ABAQUS,the sample model of cushion wood was established,and the samples with different moisture contents were numerically simulated to analyze the influence of moisture content on the mechanical properties of cushion wood.On this basis,based on the cushion wood sample with a moisture content of 14.1 %,the performance of the cushion wood containing defects(openings)was analyzed,and its effect on wood performance was studied by changing the opening position and size.(3)According to the ship ’s gravity distribution and structural design criteria,the NASTRAN software is used to calculate directly,and the strength analysis of the beams and piers in the support system is carried out respectively.The spring element is used to simulate the cushion wood,and the height of the cushion wood on the beam is adjusted to realize the stiffness optimization,and the distribution of the support system is preliminarily determined.By simulating the pier of the ship,the self-weight load is applied for finite element calculation,and the strength of the hull and support structure is checked according to the relevant specifications and standards to meet the safety requirements.(4)The strength analysis of the hull and support structure is carried out for the ship displacement condition.On the basis of the designed support system in the research content(3),the diagonal brace is added to ensure the safety of the movement.Considering the two factors of the maximum load of the floating dock hull girder and the maximum pressure load of the floating dock,the strength of the floating dock hull structure under the barge condition is checked to verify whether it meets the requirements of the specification.In this thesis,aiming at the structural strength of the mobile ship launching support system,the performance of the supporting cushion wood in the support system is deeply studied,and the influence law of the performance of the cushion wood on the bearing capacity is obtained.At the same time,the strength analysis of the supporting structure is carried out under the premise of ensuring the safety of the hull by the finite element calculation method.The research results have certain engineering value and guiding significance for the existing mobile ship launching method.