Analysis on multi-layered and functionally graded spherical pressure vessels

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Analytical models are presented for both multi-layered and functionally graded thick walled spherical pressure vessels that are subjected to uniform internal or external pressure. A double recursive algorithm is used for the n-layered vessel of which the modulus of elasticity and yield stress are assumed to change stepwise from one layer to another. In the model intended for the continuously graded one, these properties are assumed to vary in radial direction according to a power law. The elastic behaviors under the same loading conditions for such heterogeneous vessels, and the homogeneous ones alike, have been compared. The relationships between the elastic limit load (according to the yield criterion of von Mises) and the grading indices or number of layers have been investigated. As a result, it has been observed that although the difference between elastic limit load of the functionally graded and that of 2-layered pressure vessels is 70%, this difference decreases to 2% for the 32-layered one. Moreover, yielding may emerge at the inner or outer surfaces of the graded vessel depending on the load and grading parameter however it occurs at (𝑟𝑛−1)𝑡ℎ interface coordinate in the multi-layered one.

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Heterogeneous spherical pressure vessel , FGM , Multi , layered material , Elastic limit , Von Mises yield criterion

Pamukkale University Journal Of Engineering Sciences

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Pamukkale University Journal Of Engineering Sciences