“…In this way, we obtain the coefficients A j , B j , C j , D j by using the boundary conditions on the stress (2.2); the condition w(b, z) = 0 is automatically verified while, the radial displacement u A (b, z) (where the superscript A refers to the problem A) is obtained from (3.19). The solution of problem A gives so rise to an infinite sum of terms, each of them generating displacement fields w(r, z) and u(r, z) satisfying the so called semi-inverse Levinson assumptions defined in Levinson (1985) and generalized, for cross section of arbitrary shape, in Nicotra et al (1999). Hence, we define the problem B with the following boundary conditions: free loading ends,…”