Study on the mechanism of unidirectional loading rubber bulging of bionic egg-shaped shell

Shi, Zhengxian; Sun, Zhiying; Shen, Mingting; Zhang, Jian; Zhan, Ming

doi:10.1007/s00170-023-10903-6

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…It has the advantages of simpler sealing and lower equipment requirements compared to thermal gas bulging and hydroforming [15]. After research [16][17], both rubber bulging and granular medium bulging technology can effectively improve the processing accuracy of bionic egg-shaped shells.…”

Section: Introductionmentioning

confidence: 99%

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

sun,

Shi,

Shen

et al. 2024

Preprint

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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. To explore the stress and strain conditions in different stages and regions of egg-shaped shell flexible medium forming technologies under the ideal condition of considering the thickness stress, the mechanical analysis of egg-shaped shell flexible medium forming technologies is carried out. The simulation analysis and experimental verification methods are used to analyze the forming process of egg-shaped shells with different flexible mediums and verify the accuracy of the numerical analysis model. Then, in order to master the influence of flexible medium forming technologies on the plastic deformation and quality of egg-shaped shells, the influence of different flexible medium forming technologies on the plastic machining accuracy, geometric accuracy, and strength of egg-shaped shells is researched. 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 maximum strain of the egg-shaped part is 4% higher than that of the rubber medium, and the maximum thinning rate is 13.9% smaller than that of the 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 loads of the egg-shaped shell process parts with the granular medium are all higher than that of the rubber medium, and the buckling loads of the egg-shaped parts are slightly smaller than that of the rubber medium. However, taking into account the error of the egg-shaped shell flexible medium forming test, hydrostatic pressure test, and the overall buckling load distribution of the egg-shaped shell flexible medium forming process parts, it is considered that the overall strength of the egg-shaped shell with the granular medium is higher than that of the rubber medium.

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Section: Introductionmentioning

confidence: 99%

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

sun,

Shi,

Shen

et al. 2024

Preprint

Self Cite

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show abstract

“…This egg-shaped structure not only provides excellent pressure resistance but also distributes pressure evenly when subjected to external pressure. This improves overall stability [2][3][4][5]. Therefore, in deep-sea engineering, based on the design principle of the egg-shaped structure, scientists have proposed to apply the bionic eggshaped structure in engineering practice [6][7].…”

Section: Introductionmentioning

confidence: 99%

Influence of unidirectional loading pusher head structure on the deformation law of bionic egg-shaped shells in internal high-pressure bulging

Sun,

Shen,

Shi

et al. 2024

Int J Adv Manuf Technol

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A solid particle medium flexible bulging technology is proposed to solve the problems of low molding precision, poor stability, and uneven deformation that may occur when processing bionic egg-shaped shells by the traditional bulging process. By optimizing the mold parameters, such as the angle and height of the pusher head, the flow characteristics of the granular material are improved, resulting in improved machining accuracy and surface quality when molding egg-shaped plastic shells. In this paper, we utilize a ø0.8-1 mm yttria-stabilized zirconia ceramic bead to serve as a pressure-transfer medium during the granular media forming process. Several different shapes of pusher heads with cone angles of 45°, 60°, 75°, and 90° and heights of 10mm, 25mm, and 40mmwere designed and manufactured. The numerical model of simulation was verified by the analysis of strain inhomogeneity coefficient, and the maximum thinning rate at the apex of bulging of the egg-shaped test was measured and calculated. The results show that the maximum thinning rate at the apex of bulging is the largest for the pusher head with 45° cone angle and 25mm height, and the strain distribution is the most uniform and the expansion effect is the best. The study shows that the optimization of the process parameters of the pusher head shape can effectively improve the uniformity of the strain distribution and thickness distribution during the egg-shaped shell forming process, thus improving the machining accuracy of the plastic deformation of the bionic egg-shaped tube test piece.

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“…Tube hydroforming has recently attracted attention in the automotive, aeronautic, and aerospace industries [23,24]. Sun et al presented a novel approach for improving the deformation distribution and processing accuracy of egg-shaped shells by using a flexible rubber medium for unidirectional loading and bulging [25,26]. Nevertheless, the hydroforming process for tubing has the drawback of slow cycle times and necessitates expensive hardware.…”

Section: Introductionmentioning

confidence: 99%

Internal Hydroforming of Large Stainless-Steel Eggshells from Stepped Preforms

Tang

Zhang

Zhan

et al. 2023

Metals

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The internal hydroforming of large stainless-steel eggshells from a stepped preform is investigated in this paper. The nominal major and minor axes of the eggshell were 1537 and 1070 mm, respectively. The stepped preform was fabricated from thin-walled (1.9 mm thick) stainless-steel sheets and comprised twelve conical segments inscribed inside the target eggshell. The preform was then hydroformed, and its wall thickness and shape were measured. The yield load distribution and material hardening of the hydroforming process were investigated analytically. Nonlinear finite-element analyses were employed to further investigate hydroforming behaviors and the effect of weld lines on hydroforming. The experimental, numerical, and analytical results were consistent. The results confirm that, during the hydroforming process, considerable springback occurs for large eggshells, which greatly affects forming precision. However, this effect can be reduced by accounting for the strengthening effect of weld lines.

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Study on the mechanism of unidirectional loading rubber bulging of bionic egg-shaped shell

Cited by 5 publications

References 21 publications

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

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

Influence of unidirectional loading pusher head structure on the deformation law of bionic egg-shaped shells in internal high-pressure bulging

Internal Hydroforming of Large Stainless-Steel Eggshells from Stepped Preforms

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