Sequence approximation optimization based thin sheet tension VBHF (Variable Blank Holder Force) uncertainty design method

Abstract

The present invention discloses a sequence approximation optimization based thin sheet tension VBHF (variable blank-holder force) uncertainty design method. According to the method, common defects in the thin sheet tension and formation process are used as optimization targets, a VBHF is used as a design variable, and a friction coefficient is used as an uncertainty parameter. Firstly, the uncertainty parameter is described by using an interval; an uncertainty multiobjective optimization model related to the VBHF and the uncertainty parameter is established; response values of an objective function and a constraint function at an initial training sample point are obtained by using a finite element method; and on the basis, the VBHF approximation model is established by using an RBF neural network; the approximation model is combined with a genetic algorithm to carry out iteration optimization; then a sequence similarity optimization is adopted; according to an optimization result, a training sample point set and the VBHF approximation model are updated; and optimization is carried out again. By the method disclosed by the present invention, according to a design requirement of the VBHF, an optimal VBHF curve with robustness can be efficiently obtained.

Description

technical field [0001] The invention relates to an uncertain design method of thin plate tensile variable blank holder force based on sequential approximate optimization. technical background [0002] In thin plate stretch forming, the design of blank holder force is very important, which has a great influence on the forming quality and forming limit of deep drawing parts. Replacing the traditional constant blank-holding force technology with variable blank-holding force control technology can effectively improve the forming properties of materials, suppress wrinkles, cracks, springback and other defects, and improve forming accuracy. [0003] In engineering practice, due to errors in material processing, mold installation, etc., or the difficulty of accurate measurement, many parameters fluctuate, and precise values ​​cannot be given. Since the optimal solution obtained by the deterministic optimization of variable blank holder force is usually located on the boundary of t...

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Problems solved by technology

[0005] In order to solve the problem of uncertain optimization design of thin plate tensile variable blank holder force under multi-objective and nonlinear conditions in engineering practice, the present invention provides a method for uncertain design of thin plate tensile variable blank holder force based on sequential approximate optimization , and use the RBF approximation model based on sequence update and the two-layer nested optimization algorithm based on genetic algorithm to calculate the objective function interval and constraint interval and optimize the design vector

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