Stress Analysis And Optimization Design Of AP1000 Temporary Roof Structure

The AP1000 temporary roof is an important protective structure in the nuclear island building structure.Its convenience in daily hoisting has a great influence on the quality and duration of the hoisting construction.The mechanical properties of the structure determine the equipment inside the containment.The degree of protection and the safety of the nuclear island.Improving the structure of the temporary roof cover is of great significance for reducing the operational difficulty,improving the safety protection performance,saving costs and shortening the construction period.In order to solve the problem of AP1000 nuclear power plant construction,this paper takes the AP1000 temporary roof as the research object,and improves the design of the roof structure for the original structure design,such as excessive truss height,insufficient opening area and insufficient wind load capacity.The finite element software ANSYS is used to analyze the stress of the improved structure.Finally,the extended full stress method is used to optimize the section of the structural member.The main research contents are as follows:(1)Optimized the connection truss structure,opening parts,web space truss structure and running structure,reducing the height of the top truss from 6220mm to 3105mm and the opening area from 210.6m~2 to423.8m~2;for transportation and Demolition or loading The whole structure is divided into five sub-modules;and according to the structural characteristics of the top cover,the layout of the lifting points is studied.After comparing the advantages and disadvantages of the two solutions,the layout design of the eight lifting points is finally adopted.(2)Based on the finite element software ANSYS,the hoisting,normal operation and non-operation finite element models are established respectively.The feasibility of the hoisting scheme is verified by analyzing the mechanical characteristics under the hoisting conditions.The roof is analyzed under normal and non-working conditions.Stress,displacement and buckling eigenvalues were compared.The effects of the top cover on the stress and strain of the cylinder under five working conditions were compared and analyzed to verify the rationality and safety of the structural design.(3)All the components of the temporary top cover are divided into 6groups,and the cross-sectional area of the rod is iterative calculated by the extended full stress method.After the requirements of stress,displacement and stability are satisfied,the optimization of the cross-section of the rod is completed.After four optimized design,the total weight of the top cover was reduced from the original weight of86.1t to 59.8t,which reduced the weight by 31%,thereby further reducing its impact on the lower cylinder and saving costs.