Investigation of Buckling Knockdown Factors for Pressurized Metallic Cylinders Using Various Numerical Modeling Techniques of Initial Imperfections

Nonlinear postbuckling analyses are conducted to investigate the buckling KnockDown Factors (KDF) for pressurized metallic cylinders. The nonlinear analysis code, ABAQUS, is used to the postbuckling analyses. Various numerical modeling techniques are used to represent the initial imperfections of a cylinder. Measured Geometric Imperfection (MGI) and Single (or Multiple) Perturbation Load Approaches (SPLA or MPLA) are considered to model the geometric initial imperfection modeling techniques, and Single Boundary Perturbation Approach (SBPA) is used to represent the boundary imperfection modeling technique. When the internal pressures of 0 and 40 kPa, the SPLA can provide less conservative KDFs. However, the robust KDFs for the cylinder subjected to an internal pressure of 100 kPa are derived using the SBPA. These results show that the initial imperfection modeling must be appropriately selected considering the internal pressure levels of the thin-walled cylinder.