Exterior erosion effects on the buckling of pipes under external pressure

This paper presents novel predictions of the collapse pressure of initially circular pipes under external hydrostatic pressure subjected to external erosion and/or corrosion. Models with specific dimensions but varying wear depth along the pipe were created and both linear (eigenvalue) and non-linear buckling analyses using ANSYS APDL with solid shell 190 elements and Workbench with Solid 186 elements were performed. Firstly, the effects of element types on the results were investigated. Then the resulting buckling pressures were compared to investigate the changes in buckling pressure with the variation in the extent of external wear. Nonlinear analyses using ANSYS Workbench Static Structural finite element analyses were then obtained and interpreted. These results enabled the innovative aspect of this work. This was the introduction of a reduction factor to enable the effects of geometry change due to erosion/corrosion on collapse pressures using simpler buckling prediction techniques to be predicted. This unique procedure enables buckling pressures for various external wear depths using Windenburg & Trilling, von Mises and/or design charts to be predicted. This work makes considerable advances towards enabling safe buckling pressures for externally eroded/corroded pipes to be relatively easily and quickly calculated.