Optimum Design Study Of Wings Based On Reliability

As we know,weight is a significant factor which influences all kinds of the performances of airplane strongly, among them, structure of airplane has the greatest impact on weight. As an important part of airplane, wings play an important role in improving the performances of airplane, especially in the field of the structure of the quality of light. Reliability is one of the most important indexes which can guarantee the quality of wings as well, the reliability of wings affects not only the performance of airplane, but also the safety of flight. Based on the reliability optimization, the design of wings has a huge amount of benefits such as preventing the catastrophic accidents effectively, reducing the structure quality, improving the performances of airplane, shortening the development cycle, saving the development costs, reducing the repair costs. As a result, more and more aircraft design engineers apply this method in the field of aircraft design. With the development of reliability method and reliability optimization method of structure, people find it time-consuming and hard to convergence that using finite element software to solve the problem by repeating. Therefore, applying the response surface fitting theory into reliability optimization study and using response surface polynomial fitting method to calculates reliability and optimizes reliability results are in line with the engineering requirements in modern society.This thesis puts forward the "average value of absolute error minimization" response surface fitting method based on the response surface fitting method and through with (without) the cross terms of two order response surface fitting two examples are compared with the classical response surface, the results show that the new method has improved the precision. Then by solving the finite element model of a wing structure,obtaining the reliability index of the wing and with the orthogonal design method and the application of response surface fitting method, the reliability response surface approximate model of the wing is established. As the target of minimum the quality of the wing structure and constrain condition of maximum displacement and maximum stress reliability, selecting the thickness of the skin and rib plate thickness as design parameters to establish the mathematical optimization model,using the MATLAB toolbox to solve the problems. Through the comparison of this thesis optimization results and optimization result of ANSYS-workbench shows that the optimization method can be used to reduce the quality of the wing effectively, improve the precision and guide the wing structure reliability optimization in the case of wing strength reliability and stiffness reliability meeting design conditions.