Optimal method for connecting pipe structure with large openings in cylindrical shells

Abstract

The invention relates to an optimization method for a cylindrical shell large opening connecting pipe structure. The optimization method includes the steps that a BP neural network is constructed with structure characteristic parameters as an input vectors and structural stress responses as output vectors, and the BP neural network is trained to obtain a trained BP neural network; taking the shell middle plane diameter D, the opening ratio rho and the ratio of material allowable stress to internal pressure borne by the structure [sigma]<t> / P as given design parameters, taking the ratio of the effective thickness of a connecting pipe to the effective thickness of a shell delta[et] / delta[e] and an opening parameter lambda as optimization parameters, taking the effects that the structure stress responses output by the BP neural network meets the strength requirement and material for the structure is smallest in usage amount as the optimization objective which is converted into a fitness function, a genetic algorithm is constructed to optimize the wall thickness of the opening connecting pipe, and an optimization result containing delta[et] / delta[e] is obtained. The method not only can obtain the optimal structure parameter proportion meeting the strength requirement and save material, but also is easy to implement, convenient and rapid to use, and high in optimization speed.

Description

technical field [0001] The invention relates to the technical field of structural optimization design of pressure-bearing special equipment, in particular to a method for optimizing the structure of a large-opening connection pipe of a cylindrical shell. Background technique [0002] The optimal design of pressure vessels is mostly a multi-dimensional constrained nonlinear programming problem, and its optimization process is quite complicated, and sometimes it may not be possible to establish a mathematical model for optimal design through theoretical analysis methods. At present, the commonly used methods in the optimal design of pressure vessel structures are: single variable extreme value method, orthogonal design method, statistical analysis method, reliable analysis method, fuzzy design method and finite element method. [0003] In order to obtain the optimal structure, the characteristic parameters related to the structural strength should achieve the best matching rat...

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Problems solved by technology

[0003] In order to obtain the optimal structure, the characteristic parameters related to the structural strength should achieve the best matching ratio, which is difficult to achieve with conventional design methods in the case of multiple parameters. If the above design method is used for optimization, the designer should have High professional knowledge, and the design process is too complicated and cumbersome or impossible to realize, so usually the engineering designers only consider the structure to meet the strength requirements when designing, but fail to fully consider the optimal coordination of structural parameters, resulting in waste of materials, Equipment cost increase

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