| In the wreck salvage project,the lifting force configuration scheme is an important factor affecting the distribution of internal forces(shear force distribution and bending moment distribution).If the internal force is too large,it may lead to hull fracture,especially when there is a damage in the hull,the possibility of its fracture is greatly increased.Currently,the position and size of the configured lifting force mainly rely on engineering experience.This method has disadvantages such as low efficiency,not easy to learn,and the resulting configuration scheme easily makes the internal force of the wreck large.In order to overcome the above shortcomings,a floating crane lifting wreck is used as an example,and based on rigid beam theory,an intelligent optimization algorithm is introduced to optimize the wreck lifting force configuration so that the internal force is as small as possible when the wreck is off the bottom.The main research results can provide reference for the decision of lifting force configuration in the salvage project for small and medium-sized wrecks,which has important theoretical significance and practical engineering value.The main work contents and conclusions are:(1)Calculation method of internal force in shipwreck.Taking the balanced lifting of a wreck off the bottom by a floating crane as an example,the moment when the wreck is under the maximum force in the process of leaving the bottom is taken as the research object.And,its static analysis and simplification are carried out.Then,based on the rigid beam theory,a suitable formula for calculating the internal force is selected by combining the force characteristics of the wreck,and it is realized by programming on MATLAB platform.A calculation procedure with the position and magnitude of the lifting force as input and the internal force distribution of the wreck as output was obtained as the basis for the following work.(2)Optimization and analysis of lifting force configuration for a wreck.Based on the calculation program in(1),the optimization model of lifting force allocation for shipwrecks is established with input as optimization variable and output as optimization target,and a combined algorithm(both the genetic algorithm and the simulated annealing algorithm)is selected to optimize its main difficulties,and the optimal solutions of shear force and bending moment are obtained respectively.Taking the two sets of optimal solutions as initial solutions,the Pareto optimal solution of shear and bending moment are obtained by using an improved bi-objective simulated annealing algorithm for optimization.The final optimized solution is then selected from the solution set and compared with the simulated empirical solution,the comparison show that the peak shear force and peak bending moment of optimized solution are reduced by 10.46% and 30.04%,respectively.(3)Optimization and analysis of lifting force configuration for a damaged wreck.Following the research idea in(2),adding the internal force constraint requirements at the damage regions,and taking two more representative damage states with the damage opening facing upward and the damage opening facing downward as examples,the two types of damaged wrecks were analyzed and optimized respectively,and The optimization results show that: For the wreck with the damaged opening facing up,the optimized shear peak value of the wreck,shear peak value of the damaged part,the bending moment peak value of the wreck and the damaged part decreased by 9.57%,0.02%,18.72% and 20.27%,respectively.For the wreck with the damaged opening facing down,the four internal force peaks after optimization decrease by 9.68%,0.01%,22.75%and 17.89%,respectively.Then,the influence of damage length and location on the optimization results was further explored by optimizing 20 different damage states.Finally,all the research results are summarized and a user-friendly graphical user interface is designed for the optimization procedure. |
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