Abstract: Stretch forming is the basic method for aircraft skin. Defects in sheet metal stretch forming are analyzed. In order to get reasonable parameters, the idea of combing finite element analysis and optimization algorithms is adopted, and response surface method is suggested to improve the efficiency of the retrieval. Based on the analysis of the mechanism of springback in double curve skin stretch forming, the reasonable pre-stretch rate is found through the numerical simulation and NPQLP optimization algorithm under the restrictive of maximal thickness strain. According to the result both numerical simulation and experiment have verified that the strain uniformity is improved and springback is reduced 21.87%.

Key words: optimization theory, skin, stretch forming, numerical simulation