Ultimate strength of locally damaged steel stiffened cylinders under axial compression

Abstract

a b s t r a c tThis paper focuses on the load-carrying behaviour of large diameter thin-walled stiffened cylinders with local damage when subjected to axial compressive loading. The case considered in this study corresponds to the residual strength assessment of columns of floating offshore structures with damage resulting from collisions with supply vessels. Numerical simulations of axial compression tests, which examine the collapse behaviour and the ultimate strength of ring-and orthogonally stiffened cylinders dented by a knife-edged indenter, are presented. The behaviour of eight small-scale ring-stiffened cylinders and four orthogonally stiffened cylinder specimens is analysed. Finite element analyses were performed using the ABAQUS FEA software package, and a close agreement between the experimental test results and the numerical predictions was achieved. To assess the factors influencing the reduction in ultimate strength under axial compression and to clarify the progressive collapse behaviour, further analyses were performed on design examples of ring-and orthogonally stiffened cylinders, considering both intact and damaged conditions.

Dent damage identification in stiffened cylindrical structures using inverse Finite Element Method

“…To demonstrate the capability of iFEM for damage prediction, a longitudinally and transversely stiffened thin-walled cylindrical structure, which was previously considered by Cerik [39], was analysed after introducing local dent damage. The length of the cylindrical structure is 10 m and it has a circular cross-section with a radius of 3 m. There are 12 longitudinal stiffeners with a web height of 200 mm at the inner surface.…”

“…The structure can be considered as a thin-walled cylinder and the thickness of the cylinder including the stiffeners is 25 mm. There is an initial geometrical defect representing the local dent with a width of 1 m and a depth of 0.1 m [39]. The material degradation approach [47] is utilized to represent the pre-existing damage in a rather simple way.…”

“…The results show that iFEM can be simply and efficiently used for the SHM of ship structures with robust, fast and reliable results. Stiffened thin-walled cylindrical structures are one of the most common structural components of floating offshore installations [39][40][41][42][43]. Fig.…”

A Useful Manufacturing Guide for Rotary Piercing Seamless Pipe by ALE Method

“…From the beginning of the introduction, the advantages of seamless pipe (i.e., increased pressure ratings, uniformity of shape, and structural strength and fatigue under load) were highlighted. Especially, uniformity of geometry and material properties of the seamless pipe may help to reduce the possibility of stress concentration, initial deflection, and welding-induced residual stress [54] which can lead age-related structural damage [55], such as fatigue cracking and its propagation, localized dents [56], corrosion [57,58], and combined corrosion-fatigue [59,60] or corrosion stress and deformation issues [61,62]. In particular, seamless pipe is used for the drilling, rigid-production riser, and small size piping systems by considering fatigue and structural capacities subjected to various types of environmental loadings.…”

Ultimate strength characteristics of unstiffened cylindrical shell in axial compression

“…Ghazijahani and Showkati [22] developed an interaction formula to evaluate the ultimate strength of cylindrical shells under combined bending moment and external pressure. Cerik [23] reported a numerical study on the residual ultimate strength of ring-stiffened and orthogonally stiffened damaged cylindrical shells under axial compression. Eigenvalue analysis was adopted to determine the initial imperfection shape, while the imperfection magnitude was determined based on measurements.…”