Study of plastic deformation and quality of flexible medium forming of bionic egg-shaped shell

Aiming at the problems of large deviation of plastic machining accuracy and different buckling instability loads of bionic egg-shaped shells under different flexible medium forming technologies, it is proposed to adopt unidirectional loading rubber bulging and granular medium bulging technologies of bionic egg-shaped shells. By comparing the plastic machining accuracy, geometric accuracy, and strength of bionic egg-shaped shells with different flexible mediums, the machining accuracy and overall quality of bionic egg-shaped shells can be improved. In order to explore the stress and strain conditions at different stages and in different regions of the egg-shaped shell flexible medium forming technologies under the ideal case considering the thick directional stress conditions, a mechanical analysis of the egg-shaped shell flexible medium forming technologies is carried out. The combination of numerical analysis and experiment is used to analyze the forming process of egg-shaped shell under the action of different flexible mediums, and the accuracy of the numerical analysis model is verified. And then, through the study of the influence of different flexible medium forming technologies on the plastic processing accuracy, geometric accuracy, and strength of the egg-shaped shells, the plastic deformation and quality of the egg-shaped shell is mastered by the influence law of the flexible medium forming technology. The study shows that the results of the numerical analysis of the egg-shaped shell flexible medium forming technology have an average error of no more than 11% with the test, and the numerical analysis model can be considered accurate. Moreover, the plastic machining accuracy of egg-shaped shell process parts and egg-shaped parts with granular medium is better than that of rubber medium. The geometric accuracy deviation of the egg-shaped part of the egg-shaped shell with the granular medium is 10% smaller than that of the rubber medium, and the process parts are also superior to the rubber medium. The buckling load of the egg-shaped shell process parts under granular medium are higher than that of the rubber medium, while the egg-shaped parts are slightly smaller. Considering the experiment error and the overall buckling load distribution, the overall strength of the egg-shaped shell is higher under the action of granular medium.