A computational strategy for the analysis of damage in composite pipes

The aim of this work is the determination of the influence of manufacturing defects on the behavior of composite pipes. We present an efficient numerical tool to solve this problem which relies on a strategy dedicated to pipes. Since most of the harmful manufacturing defects are located at the ends of the pipes, a complete 3D calculation is not necessary and only the ends are analyzed finely. The center of the pipe is modeled as an elastic beam and the ends as 3D nonlinear zones. The connection between the beam model and the end models is carried out using the Saint-Venant solution of the elastic problem, so that no spurious effects occur near the connection zone. This Saint-Venant solution is built from the exact beam theory. The nonlinear end problem is solved by a traditional method (secant Newton), but each elastic stage benefits from a particular treatment. In order for each 3D elastic problem to be solved efficiently, it is uncoupled into a set of dedicated 2D problems using a Fourier series expansion. Transfer between the 2D and 3D states is achieved using fast Fourier transform.