Buckling of internally-pressurized spiral-welded steel pipes under bending

Abstract

The mechanical behaviour of spiral-welded large-diameter steel pipes is simulated, with the purpose of defining their bending deformation capacity against local buckling. The steel pipes are candidates for hydrocarbon onshore pipeline applications with diameter-to-thickness ratio D/t equal to 53 and 69, and are subjected to longitudinal bending under internal pressure levels ranging from zero to 75% of the nominal yield pressure. Initial geometric imperfections are considered in the form of shortwave axial wrinkles and girth weld misalignment, whereas residual stresses are taken into account as computed from a special-purpose finite element simulation of the spiral bending process, which also accounts for both decoiling process and hydrotesting. The sensitivity of critical bending curvature on the level of internal pressure is examined, the value of buckling wave length is discussed and the effects of hydrotesting after spiral forming on structural performance are also investigated. Finally, the value of critical bending curvature is compared with analytical and empirical equations, widely used in pipeline design applications. The results of the present study determine the main parameters affecting the buckling deformation capacity of large-diameter spiral welded pipes in a strain-based design framework, and indicate that these pipes can be used in demanding pipeline applications, such as in geohazard areas.

The effect of spiral cold-bending manufacturing process on pipeline mechanical behavior

“…The paper is aimed at examining numerically the effect of manufacturing process on the structural (buckling) performance of spiral welded pipes, used in demanding onshore applications, and in moderately deep offshore environment. The numerical simulations account for the effects of spiral cold forming process and their material behavior, with emphasis on their compressive strain capacity under bending and pressure loading conditions, extending the work presented in [13] [14].…”

Seismic fragility assessment of high-rise stacks in oil refineries

“…Past research (Karamanos 1996;Diamanti et al 2011;Papadaki et al 2018) suggests that the effect of typical operating pressure on the elastic stiffness of pressure vessels is negligible and was thus disregarded in the structural model developed for estimating the seismic response of the process tower. The tower is 30m high, having an internal diameter equal to 2.6 m. The shell thickness of the tower was defined on the basis of the internal pressure and not its buckling strength.…”

Investigation of fatigue strength evaluation of welded structure on spirally welded tank wagon via finite element analysis

“…Spirally welded pipes, or also known as "HSAW" pipes, have become industrially remarkable for hydrocarbon transport under high pressure [12,13]. Metallurgical structure improvements and mechanical performance enhancement, as well as developments in the production process, have further increased the utilization of such pipes [13]. It is a more economical and effective method in the production of thin-walled and large-diameter pipes.…”