Research on hydro-forming of spherical shells with different preform types

Zhang, R.; Zhang, W.W.; Shi, Yuan

doi:10.1007/s00170-017-0350-x

Cited by 11 publications

(2 citation statements)

References 11 publications

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“…However, it was recognized that, unlike cylindrical shells, spherical shells were more suitable for using as junction elements because the highly symmetrical structure of a spherical shell facilitated hole opening. In addition, surface stress was evenly distributed on spherical shells [14][15][16]. The surface of a spherical shell experienced less stress compared with other structures under the same external pressure in [17].…”

Section: Introductionmentioning

confidence: 98%

Numerical and Experimental Buckling and Post-Buckling Analyses of Sphere-Segmented Toroidal Shell Subject to External Pressure

Zhang

Wang

2022

Metals

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This study determined the buckling characteristics of sphere-segmented toroidal shells subjected to external pressure. The proposed toroidal vessel comprises six spheres and six rings. Two laboratory models with the same nominal dimensions were manufactured, measured, tested, and evaluated. To investigate whether sphere-segmented toroidal shells are imperfection-sensitive structures with closely spaced eigenvalues, the subspace algorithm was applied to evaluate the first 50 eigenmodes, and the modified Riks algorithm was used to obtain post-buckling characteristics. The results indicated that the deviation between the results of the experimental and numerical analyses was within a reasonable range. The proposed sphere-segmented toroidal shells were highly imperfection-sensitive structures with closely spaced eigenvalues. Subsequently, imperfection sensitivity analysis confirmed this conclusion. In numerical analyses, the first eigenmode could be considered as the worst eigenmode of sphere-segmented toroidal shells. The trend of the equilibrium path of sphere-segmented toroidal shells was consistent with spherical shells, revealing instability. In addition, ellipticity and completeness exerted a negligible effect on the buckling load of sphere-segmented toroidal shells.

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Section: Introductionmentioning

confidence: 98%

Numerical and Experimental Buckling and Post-Buckling Analyses of Sphere-Segmented Toroidal Shell Subject to External Pressure

Zhang

Wang

2022

Metals

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“…Yuan [3] further expanded upon this technology. Zhang and his co-researchers [4] achieved the formation of spherical shells through hydroforming technology using various preformed structures. Some scholars [5,6] went a step further, successfully producing a double-layer spherical shell.…”

Section: Introductionmentioning

confidence: 99%

Wrinkling of Toroidal Shells in Free Hydroforming

Liu,

Zhang,

Zhan

et al. 2024

JMSE

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In this study, we investigated toroidal shell wrinkling in free hydroforming. We specifically focused on toroidal shells with a regular hexagonal cross-section. Membrane theory was used to examine the distribution of stress and yield load in both preform and toroidal shells. The wrinkling moment was then predicted using an empirical formula of shell buckling. In addition, the wrinkling state was investigated using a general statics method, and the free hydroforming of toroidal shells was simulated using the Riks method. Subsequently, nonlinear buckling and equilibrium paths were analyzed. A toroidal preform was manufactured, and free hydroforming experiments were conducted. Overall, the experimental results confirmed the accuracy of the theoretical predictions and numerical simulations. This indicates that the prediction method used in the study was effective. We also found that wrinkling occurs during hydroforming in the inner region of toroidal shells due to compressive stress. Consequently, we improved the structure of the toroidal shells and performed analytical calculations and numerical simulations for the analysis. Our results indicate that wrinkling can be eliminated by increasing the number of segments on the inner side of toroidal preforms, thereby improving the quality of toroidal shells.

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Influence of welding distortion of preform shell on shape variation during hydro-forming process of ellipsoidal shell

Zhang

Shi

2017

Int J Adv Manuf Technol

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Research on hydro-forming of spherical shells with different preform types

Cited by 11 publications

References 11 publications

Numerical and Experimental Buckling and Post-Buckling Analyses of Sphere-Segmented Toroidal Shell Subject to External Pressure

Numerical and Experimental Buckling and Post-Buckling Analyses of Sphere-Segmented Toroidal Shell Subject to External Pressure

Wrinkling of Toroidal Shells in Free Hydroforming

Influence of welding distortion of preform shell on shape variation during hydro-forming process of ellipsoidal shell

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