Controlling the Change in the Shape of a Cylindrical Shell Subjected to External Hydrostatic Pressure

Analytic and numerical analysis for the initial non-linear elastic stage of changing in the shape of a circular shell subjected to a high-pressure liquid is performed, with the shell being under two rigid constraints: an external cylindrical cavity and/or an internal rod.In this stage, the emergence of alternating bulges and depressions is governed by the balance between the nonlinearity and dispersion effects.In the framework of the Cosserat theory, the dependence of the curvature of the shell cross-section on the external pressure is obtained.Knowing the curvature make it possible to restore the form of the cross section with the methods of the differential geometry.It is shown that unwanted wave-like folds and rigid ribs on the deformed shell surface can be eliminated by suitably selecting the constraints.Cost-efficient ways of producing hollow articles from pipe billets with the hydrostatic pressure method are discussed.