Expansion of Thick-Walled Cylinders Fabricated From Cold Bent Plates

The problem of the elastic-plastic expansion by internal pressure of thick-walled cylinders that were fabricated by cold bending initially flat plate is analyzed by the use of the principal shear theory of piecewise linear plasticity. The strain-hardening material may have been initially anisotropic and may have developed inhomogeneity and further anisotropy due to the cold bending. The numerical example which is then solved shows that, even for materials which have similar initial yield properties before bending, there are substantial differences in terms of the pressure at which initial yielding occurs in the cylinder and in terms of subsequent cylinder behavior. Those differences in cylinder behavior occur because the materials which are compared have yield surfaces which behave differently when the material is plastically strained.