Experimental study on the buckling and post-buckling behavior of thin-walled cylindrical shells with varying thickness under hydrostatic pressure

The application of thin-walled cylindrical shells, as the essential structural members, has been known for engineers and functional duty of them is basic necessaries of modern industries. These structures are prone to fail by buckling under external pressure which could be happened during discharging or wind load. Although the buckling capacity of the shells depends principally on two geometric ratios of "length to radius" (L/R) and "radius to thickness" (R/t), but the effect of thickness variation on the behavior of the shells is complicated to be studied. On the other hand, the buckling strength of thin cylindrical shells is sensitive to the magnitude and shape of geometric imperfections. The effect of thickness variation and geometric imperfections on the buckling and postbuckling behavior of cylindrical shells is experimentally investigated in this paper. Top end of the specimens has conical roof and the bottom end has simply supported conditions. The measured data and obtained results are reported for the specimens under the effect of hydrostatic external pressure. Each specimen has different variation in thickness along its length. The slender parameters of tested shells are L/R = 2, 1, 0.5 and R/t = 500, 600. In addition, the considerable effect of circumferential and vertical weld line on the buckling strength and mode shapes is verified.

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