Hotpipe project: Capacity of pipes subject to internal pressure, axial force and bending moment

Several studies have been performed in order to better understand the local buckling of pipes subjected to internal pressure, axial load and bending moment. Experimental tests have been carried out and simplified analytical solutions have been developed in order to predict the pipe bending moment capacity and the allowable level of deformation. In recent years, the comparison of experimental tests and Finite Element Analysis (FEA) results, obtained with standard finite element structural codes available on the market such as ABAQUS, ADINA, ANSYS, etc., has demonstrated the capability of FEA to give robust and reliable results. Therefore, in the present study finite element methods have been used to create a "numerical testing laboratory" with the following advantages with respect to experimental tests: a better control of the relevant parameters affecting the pipe behaviour, an accurate monitoring of the loads and deformations along both the pipe axis and pipe circumference, a larger amount of information as regards both the stresses and the strains on the pipe model, a cheaper cost. This paper describes the main findings of the study performed in the HOTPIPE project aiming at establishing the failure mechanisms and limit state formulations of pipes subjected to internal pressure, bending moment and axial compression.