Structural Dynamics Optimization Design Based On Surrogate Model Of Panel With Two L Stiffeners

Stiffened plate is an important part of aerospace structure, which will be affected by different forms of random loads in the process of flight. Fully understanding of the dynamic characteristics of stiffened plate is the key to design this kind of structure. On the other hand, improving the structure performance and reducing weight have been an important theme of modern aerospace structural design. The purpose of this paper is to study model updating,structure optimization design of typical stiffened plate, and verify the effectiveness of optimization by experiments.The commonly used experimental design methods, approximate methods and evaluation index of surrogate models are briefly introduced. Combined with typical function, modeling accuracy was compared and the applicability of the various models in deterministic simulation is presented. In addition, uncertainty interference was simulated by introducing the Gaussian white noise to the original experimental design points and the ability of these surrogate models when processing noise was compared.In order to reflect the real structure shape corresponding to each set of iterative parameters in the process of optimization design, a parametric similar structure of stiffened plate with double L stiffener was established based on the parametric modeling function of MSC.Patran. To describe the ganged bolt connection, the elements with Bush and Beam properties were used and structural response error caused by different connection ways of modeling was compared. Modal analysis of stiffened plate similar structure with double L stiffener was conducted. By calculating the frequency error and Modal Assurance Criterion, the similarity between calculating modal analysis and experimental modal analysis was estimated. The sensitivity analysis of five modals with relatively higher MAC to the twenty four primary stiffness parameters was conducted. According to the results of sensitivity analysis, three tangential stiffness was selected as the parameters to update the five modals. The comparing result of the corresponding order frequency error between models before and after updating indicated that model updating can narrow the difference between calculation and test. On the basis of updated model and the interface between numerical calculation and finite element analysis, the surrogate models of constraint function and objective function to design parameters were constructed. Finally, the maximum of stress RMS in the designated area of stiffened plate similar structure with double L stiffener was optimized by using GA and PSO optimum design method on the finite element model and surrogate models. By conducting experimental test of structures before and after optimization and comparing the value and location of the maximum of stress RMS, the feasibility of optimization design scheme is validated.