ABSTRACT
This chapter illustrates the computation of the numerical strain values of plies embedded in standard oil pipes under internal pressure. The embedded plies move together and take the equilibrium strains as the laminate cools from peak temperature (PT) to operating temperature. The preservation of circularity ensures that all plies have the same global equilibrium strain. The analysis of durability requires the strains in the local ply frame. The computation of the residual hydric strains on ± 55 plies follows the same protocol to compute the residual thermal strains. The reader may wonder why the residual thermal and hydric strains have opposite signs. The reason is simple and obvious. In the thermal case, the laminates shrink from a high stress-free temperature PT whereas in the hydric case they expand from a stress-free dry condition. The non-anchored pipeline is pressurized to develop a 2:1 loading, meaning the hoop force resultant is twice as large as the longitudinal force resultant.
