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Flambage de coques cylindriques minces sous chargements combinés : pression interne, compression, flexion et cisaillement

Abstract : The stability of thin cylindrical shells has been studied for decades, but despite the accumulated knowledge on the subject, important questions remain, in particular regarding the design of such structures. The effect of geometrical imperfections is now well understood, but old design recommandations resulting from purely empirical approaches, are still used. The NASA SP8007 recommendation (1968) is one them, and leads to conservative designs. This rule is used in particular for the design of the Ariane 5 launcher. Indeed, the Principal Cryogenic Stage is made of thin cylindrical shells, subjected throughout the structure’s life cycle to a combination of loadings, and hence prone to possibly disastrous structural instabilities. It is is then necessary to better understand those phenomena in order to improve the design methods for relatively long (1 < L/R < 3) and thin (250 < R/t < 1500) shells. Our work is based on both numerical and experimental approaches. Numerical tools are used, through a relevant choice of the critical imperfections, to build a new design recommendation and study the influence of different parameters (geometrical or material). Experiments took an important place in our research, and the large experimental campaign allowed us to validate the numerical results for different configurations, and to better understand the physics of the problem as well. These two aspects of our study also enabled us to clarify the interaction between different loadings (internal pressure, compression, bending and transverse shear), which is today more or less understood, according to the case.
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  • HAL Id : tel-00782117, version 1

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André da Silva. Flambage de coques cylindriques minces sous chargements combinés : pression interne, compression, flexion et cisaillement. Autre. INSA de Lyon, 2011. Français. ⟨NNT : 2011ISAL0078⟩. ⟨tel-00782117⟩

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