Harmonic analysis of measured initial geometric imperfections in large spiral welded carbon steel tubes

Sadowski, Adam J.; Es, S.H.J. van; Reinke, Thomas; Rotter, J. M.; Gresnigt, A.M.; Ummenhofer, Thomas

doi:10.1016/j.engstruct.2014.12.033

Cited by 28 publications

(11 citation statements)

References 47 publications

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“…In the analysis of thin-walled shells with large values of D/t ratio, initial geometrical imperfections are considered a paramount factor in determining the resistance against local buckling [32]. Although the tubes considered in the present work have significantly lower values of D/t ratio than the shells considered in shell buckling analysis, initial imperfections are expected to have an influence on buckling location and bending moment capacity.…”

Section: Measurements Of Initial Imperfectionsmentioning

confidence: 80%

“…This locally higher ovalisation could induce local buckling at these locations, since the ovalisation increases the local radius of the shell cross section in the compression area of the tube. The fact that the local radius of the shell greatly influences the resistance to local buckling is well known [32]. On the other hand, a locally larger bending curvature at these locations due to differences in yield strength and tube wall thickness over the specimen length can be the underlying cause of both a larger ovalisation and earlier local buckling at these locations.…”

Section: Results Of Ovalisation Measurementsmentioning

confidence: 99%

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Ultimate bending capacity of spiral-welded steel tubes – Part I: Experiments

Gresnigt

Vasilikis

et al. 2016

Thin-Walled Structures

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The present investigation refers to the bending capacity of spiral-welded steel tubes. The first part of this investigation presents the results of a full-scale experimental program, aiming to investigate the structural behavior of large-diameter spiral-welded steel tubes under bending. A companion paper (Part II) is also published which further studies the behavior of these elements numerically, using finite element simulations.The testing program presented in Part I consists of thirteen 42-inch-diameter spiral-welded steel tubes with D/t ranging between 65 and 120. Some of the tubular specimens contain girth welds and coil connection welds, which are shown to penalize the ultimate bending capacity of the tubes. Extensive measurements of initial imperfections and material properties are performed for each tubular specimen. The material properties of the specimens are investigated through both uniaxial tensile and compression coupon tests. A series of large-scale four-point bending tests is performed to determine the structural behavior of the tubes, resulting in local buckling failure of the tubes under consideration.The bending behavior of the thirteen specimens is documented extensively. The study offers information with regard to the ultimate bending resistance of the specimens. In addition, the full moment-curvature equilibrium path is presented, supplemented by measurements on the development of cross sectional ovalisation and tube wall wrinkling during the bending tests.

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Section: Measurements Of Initial Imperfectionsmentioning

confidence: 80%

Section: Results Of Ovalisation Measurementsmentioning

confidence: 99%

Ultimate bending capacity of spiral-welded steel tubes – Part I: Experiments

Gresnigt

Vasilikis

et al. 2016

Thin-Walled Structures

Self Cite

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“…Recent tests on Class 3 and 4 tubes were made at Karlsruhe Institute of Technology and Delft University [6]. The measured imperfections were found to place them mostly in the lowest FQC Class C, though some had even larger local deviations [13,14]. To obtain reasonable predictions of these tests, it is necessary to include the length effects, as illustrated in Fig.…”

Section: Ovalisation and Length Effectsmentioning

confidence: 99%

05.15: Development of circular tube slenderness classifications under axial and bending actions

Rotter

Sadowski

2017

ce papers

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Local buckling in circular tubes differs from that in cross-sections formed from flat plate elements (I, H, RHS etc.) because the latter retain their original shape up to the point of local buckling and plates are not very sensitive to minor geometric imperfections. By contrast, the curved form of the circular tube or cylindrical shell is very sensitive to minor imperfections and under bending is also strongly affected by geometric nonlinearity when the tube is significantly long. The classification of circular hollow tubular sections (CHS) into Classes 2, 3 and 4 is thus more complicated than for flat plate sections. It may be also noted that the "effective section" treatment of flat plates in Class 4 cannot be used for cylindrical shells. These differences, often ignored, have led to a very wide discrepancy in the classification rules for tubes in different international standards. This paper sets out a clear description of the factors behind the development of new classification rules for CHS designed for adoption into EN 1993-1-1 [1]. The effects of length, full and partial plasticity, imperfections and cross-section distortion are all included using individual provisions. It is also believed that these are the first rules to attempt a rigorous treatment of the resistance of Class 3 CHS subject to both bending and axial compression. The fully plastic resistance of tubes under axial force and bending is also treated with great precision. The formulation is novel, so may prove interesting to others who seek to develop similar rules for other structural shapes.

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“…Girth welding is a key procedure used in pipe construction, primarily influenced by welding technology and external environments [ 1 ]. During melting and solidification of metals, some gases are inevitably retained in the metal, resulting in the formation of pore defects [ 2 – 4 ]. Pore defects are a typical volumetric defect observed in pipe girth welds.…”

Section: Introductionmentioning

confidence: 99%

Investigation on size tolerance of pore defect of girth weld pipe

Shuai

2018

PLoS ONE

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Welding quality control is an important parameter for safe operation of oil and gas pipes, especially for high-strength steel pipes. Size control of welding defect is a bottleneck problem for current pipe construction. As a key part of construction procedure for butt-welding of pipes, pore defects in girth weld is difficult to ignore. A three-dimensional non-linear finite element numerical model is established to study applicability of size control indices based on groove shape and softening phenomenon of material in heat-affected zone of practical pipe girth weld. Taking design criteria of pipe as the basis, basic tensile, extremely tensile and extremely compressive loading conditions are determined for pipe stress analysis, and failure criteria based on flow stress is employed to perform stress analysis for pipe girth weld with pore defect. Results show that pipe girth welding stresses of pores at various radial locations are similar. Whereas, stress for pores of different sharpness varied significantly. Besides, tolerance capability of API 5L X90 grade pipe to pore defect of girth weld is lower than that of API 5L X80 grade pipe, and size control index of 3 mm related to pore defect in current standards is applicable to API 5L X80 and X90 grade girth welded pipes with radially non-sharp pore defects.

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Harmonic analysis of measured initial geometric imperfections in large spiral welded carbon steel tubes

Abstract: 26.3.15 KB. Ok to add accepted version, subject to 12 months embarg

Cited by 28 publications

References 47 publications

Ultimate bending capacity of spiral-welded steel tubes – Part I: Experiments

Ultimate bending capacity of spiral-welded steel tubes – Part I: Experiments

05.15: Development of circular tube slenderness classifications under axial and bending actions

Investigation on size tolerance of pore defect of girth weld pipe

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