PSI - Issue 79

Abubakr E.S. Musa et al. / Procedia Structural Integrity 79 (2026) 206–216

208

2. Experimental program 2.1. Materials The material used in this investigation is a hollow cylindrical specimen made of carbon steel with a welded square base plate. The following sub-sections describe its geometry and material properties. 2.1.1 Geometry The specimen comprises a hollow circular tube with a uniform and smooth surface. The outer diameter is 127 mm, the inner diameter is 121 mm, and the wall thickness is 3 mm. The cylinder's height is 470 mm. The cylindrical section is welded to a square base plate with a side dimension of 200 mm and 8 mm thickness, welded at the base of the cylinder to achieve a strong connection (See Fig. 1.).

Fig. 1. Steel tube dimensions (in mm)

2.1.2 Material properties The specimen is made of carbon steel, a widely utilized material in structural applications due to its combination of strength, ductility, and affordability. The cylinder and base plate are joined using a welding process, as indicated by the visible weld bead around the joint. The specimens are designed to evaluate the specimen’s buckling behavior under axial compressive loads and for the validation of the FE modeling results. The steel exhibited a yield strength of 358 MPa, an ultimate strength of 387 MPa, and an elastic modulus of 209 GPa based on the measured average values.

2.2. Test matrix Table 1 shows specimens details. The specimens are divided into two main groups: 1. Intact specimens (T1-1, T1-2): with no thickness reduction to be used as reference.

2. Reduced-thickness specimens (T2-1 to T4-2): specimens with varying levels of thickness reduction ( Δ t), ranging from 1.0 mm to 2.0 mm, in increments of 0.5 mm. These were made to simulate the corrosion induced thickness reduction. Two replicates were used for each reduction level. For the reduced-thickness specimens, the area of thickness reduction is localized at the middle section of the tube. The reduced section dimensions are consistent: 100 mm width (B) and 80 mm height (L), as in Fig. 1. The purpose of specimen variation is that the T1 group provides the baseline mechanical response of intact tubes without damage or