Finite element prediction of the ultimate collapse strength of casings

Accurately predicting the ultimate collapse strength is very important for casing design. For an infinitely long thick-walled casing under external pr essure, a finite element method (FEM) model has been proposed to obtain a b etter understanding of the ultimate collapse strength of a casing. A very c areful comparison with a series of experimental data has been conducted to verify the accuracy and reliability of the proposed FEM model. In addition, the predicted post-collapse behaviour compares well with the experimental test data. The validation proves that, if the material behaviour and imperf ection variables are known, the ultimate collapse strength can be predicted to a satisfactory degree of accuracy. The major factors that affect the ul timate collapse strength of a casing have been fully investigated using the proposed FEM model.