Measurement and Characterization of the Initial Geometric Imperfections in High Strength U-ing, O-ing and Expanding Manufactured Steel Pipes

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Muntaseer Kainat ◽  
J. J. Roger Cheng ◽  
Michael Martens ◽  
Samer Adeeb
Keyword(s):  
High Resolution ◽  
Manufacturing Process ◽  
Pipe Wall ◽  
Initial Imperfection ◽  
High Strength ◽  
Geometric Imperfections ◽  
Pipe Wall Thickness ◽  
Steel Pipes ◽  
Initial Geometric Imperfections

The geometric imperfections in high strength U-ing, O-ing and expanding (UOE) manufactured pipes are investigated in this paper using a high-resolution 3D surface scanner, and a reverse engineering and inspection software. The geometric analyses show that the initial imperfection patterns in the UOE manufactured pipes are not at all random, although the magnitudes of imperfections may vary across specimens. These patterns of outside radii and pipe wall thickness imperfections consistently appear along the length of the specimens regardless of their D/t ratios and manufacturer. The sources of these imperfections can potentially be traced back to the UOE manufacturing process.

Effects of the Initial Geometric Imperfections on the Buckling Behavior of High-Strength UOE Manufactured Steel Pipes

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Muntaseer Kainat ◽  
Meng Lin ◽  
J. J. Roger Cheng ◽  
Michael Martens ◽  
Samer Adeeb
Keyword(s):  
High Strength ◽  
Sensitivity Study ◽  
Element Analysis ◽  
Geometric Imperfections ◽  
Geometric Imperfection ◽  
Steel Pipes ◽  
Buckling Behavior ◽  
Measurement Results ◽  
Buckling Resistance ◽  
Initial Geometric Imperfections

The effects of the initial geometric imperfections on the buckling response of grade X-100 UOE manufactured pipes are studied through finite element analysis (FEA). The initial geometric imperfections had been previously measured and quantified in terms of deviations in outside radius (OR) and wall thickness. The measurement results are used to develop imperfection models to be incorporated into buckling analysis. The OR deviation is seen to have insignificant effects on the buckling behavior, while the effects of thickness deviation are seen to be profound for both unpressurized and pressurized pipes. The geometric imperfection models are further investigated through a sensitivity study to isolate the most influential imperfection aspects on the buckling resistance of UOE pipes. A parametric study is carried out using these models and shows that excluding geometric imperfections will always result in overprediction of buckling capacity irrespective of D/t ratios.

API 5L X80 ERW Pipes: TenarisConfab and Usiminas Development

2006 ◽  
Author(s):  
Juliana E. Roza ◽  
Marcelo C. Fritz ◽  
Marco A. Tivelli ◽  
Ronaldo C. Silva ◽  
Lu´cio S. Miranda ◽  
...  
Keyword(s):  
Pipe Wall ◽  
High Strength Steels ◽  
High Strength ◽  
Mechanical Resistance ◽  
Electric Resistance ◽  
Pipe Wall Thickness ◽  
High Toughness ◽  
Operation Costs ◽  
Electric Resistance Welding ◽  
Hot Rolled

The utilization of high strength steels can decrease, both, installation and operation costs of a new pipeline, since the increase of mechanical resistance can reduce the pipe wall thickness and, consequently, the weight of the pipe. For this purpose, the manufacture of electric resistance welding (ERW) pipes is recent, and it comes as an opportunity for gas pipelines, mainly onshore projects. As a function of their larger productivity, ERW pipes are more economically attractive than those produced by seamless and SAW processes. TenarisConfab and Usiminas, through studies and investments in manufacturing processes, have been working to increase their skills, in order to supply API 5L X80 ERW pipes. The steel elaborated by Usiminas is low C, high Mn, Nb, V and Ti microalloyed, and with additions of Cr and Mo, aiming to produce hot rolled coils with acicular microstructure, achieved as a combination between its chemical composition and higher cooling rates after hot rolling. The results in φ18” (457 mm) × 0,469” (11,91 mm) pipes are presented in this article. High toughness values reached at very low temperatures suggest that X80 ERW pipes developed by TenarisConfab and Usiminas may be an excellent option of choice for onshore projects that request pipes in diameters up to 20” (508 mm) and thickness up to 0.500” (12.7 mm).

ELASTIC BUCKLING OF EXTERNALLY-PRESSURIZED IMPERFECT TOROIDAL SHELLS

2001 ◽  
Vol 01 (01) ◽  
pp. 31-45 ◽  
Author(s):  
GERARD D. GALLETLY
Keyword(s):  
Initial Imperfection ◽  
External Pressure ◽  
Elastic Buckling ◽  
Geometric Imperfections ◽  
Buckling Modes ◽  
Initial Imperfections ◽  
Numerical Studies ◽  
Initial Geometric Imperfections ◽  
Sinusoidal Buckling ◽  
Toroidal Shells

This paper summarizes the results of numerical studies into the effects of initial geometric imperfections on the elastic buckling behaviour of steel circular and elliptic toroidal shells subjected to follower-type external pressure. The types of initial imperfection studied are (a) axisymmetric localized ones and (b) sinusoidal buckling modes. The principal localized imperfections studied are (i) circular increased-radius "flat spots" and (ii) smooth dimples. The buckling pressures pcr of circular toroidal shells were not very sensitive to initial imperfections. With elliptic toroids, whether the shell was sensitive to initial imperfections or not depended on the ratio k(≡ a/b) of major to minor radii of the section. The shells on the ascending part of the pcr versus k curve behaved like circular toroidal shells, i.e. they were not sensitive to initial imperfections. However, the behaviour of elliptic toroids on the descending part of the versus k curve was very different. The numerical results quoted in the paper are for limited ranges of the geometric parameters. It would be useful to extend these ranges, to explore the effects of plasticity and to conduct model tests on imperfect steel models to verify the conclusions of the numerical studies.

Characterization of the Welded-Joint of High-Strength High-Toughness Seamless Steel Pipe under High-Cycle Fatigue Condition

2017 ◽  
Vol 896 ◽  
pp. 202-208
Author(s):  
Qing Chao Tian ◽  
Xian Ping Dong ◽  
Hai Chao Cui ◽  
Ke Xu
Keyword(s):  
High Cycle Fatigue ◽  
Welded Joint ◽  
Weld Zone ◽  
High Strength ◽  
Cycle Fatigue ◽  
Steel Pipes ◽  
Fine Grain ◽  
The Matrix ◽  
Bainite Microstructure

The welded joint of a S890QL grade steel pipes containing 1.2% Ni have been prepared to characterize the use performance under high cycle fatigue test. It has been found that the fatigue strength of the welded joint is 290MPa with a fatigue life of more than 10 million cycles, and the obtained Basquin equation is σa=488*(2N)-0.02758 . It is found that the steel exhibits the whole bainite microstructure when the cooling rate is less than 1°C/s. The welded joint is divided into the weld zone, the coarse grain zone, the fine grain zone, the softening zone and the matrix. The fine grain characteristic in the welded area determines the good anti fatigue performance of the investigated steel.

Influence of Girth Weld Flaw and Pipe Parameters on the Critical Longitudinal Strain of Steel Pipes

2012 ◽  
Author(s):  
Celal Cakiroglu ◽  
Kajsa Duke ◽  
Marwan El-Rich ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Wall Thickness ◽  
Tensile Strain ◽  
Critical Strain ◽  
Pipe Wall ◽  
Pipe Wall Thickness ◽  
Strain Capacity ◽  
Steel Pipes ◽  
Tensile Strain Capacity ◽  
Maximum Minimum

The design of steel pipelines against longitudinal loading induced by soil movement and temperature requires an understanding of the strain demand induced by the environment in comparison with the strain resistance of the pipes. Girth weld flaws have been identified as the potential location of failure under longitudinal tensile strains due to being the least ductile. Strain based design for the prediction of the longitudinal tensile strain capacity of steel pipes have been extensively studied by Wang, et al and included in the Canadian standards association code of practice CSA Z662.11 [1]. The extensive track record of tests have culminated into two sets of equations for the critical strain in girth welded pipes with surface breaking and buried defects as functions of the different pipe and flaw parameters. The CSA Z662.11 strain capacity equations were developed using wide plate tests with the obvious limitation of the inability to consider the effect of the internal pressure of the pipe. However, recent studies by Wang et al led to the development of a new set of equations that predict the tensile strain capacity for pipes with an internal pressure factor of 0.72. This paper analyses the two critical strain equations in CSA Z662-11 to understand the effect of different girth weld flaw and pipe parameters on the expected behavior of pipes. Also the critical strain equations developed in [2]have been analysed and compared to the equations in CSA Z662-11. Using the equations in CSA Z662-11, a 34 and 36 full factorial experimental design was conducted for the planar surface-breaking defect and the planar buried defect respectively. For the case of surface breaking defects the dependence of the tensile strain capacity (εtcrit) on apparent CTOD toughness (δ), ratio of defect height to pipe wall thickness (η), ratio of yield strength to tensile strength (λ) and the ratio of defect length to pipe wall thickness (ξ) has been studied. εtcrit has been evaluated at the maximum, minimum and intermediate values of each parameter according to the allowable ranges given in the code which resulted in the evaluation of εtcrit for 81 different combinations of the parameters. The average value of εtcrit at the maximum, minimum and middle value of each parameter has been calculated. The visualization of the results showed that η, δ and ξ have the most significant effect on εtcrit among the four parameters for the case of surface breaking defect. Similarly for buried defects the dependence of εtcrit on δ, η, λ, ξ, and the pipe wall thickness (t) has been studied. The evaluation of εtcrit for all possible combinations of the maximum, intermediate and minimum values of the 6 parameters resulted in εtcrit values for 729 different combinations. The variation of the average εtcrit over the maximum, intermediate and minimum values of the parameters showed that δ, ψ, ξ and η are the parameters having the greatest effect on εtcrit for the case of a buried defect. Further investigations could be carried out to determine suitable upper and lower bounds for the parameters for which no bounded range is defined in the CSA Z662-11 code.

Analysis of Ultimate Bearing Capacity and Parameters of Steel Support Cutting Pipe Roofing Structure

2021 ◽  
pp. 036119812110597
Author(s):  
Bo Lu ◽  
Wen Zhao ◽  
Xi Du ◽  
Shengang Li ◽  
Yongping Guan ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Failure Mode ◽  
Wall Thickness ◽  
Pipe Wall ◽  
Ultimate Bearing Capacity ◽  
Steel Pipe ◽  
Pipe Wall Thickness ◽  
Steel Pipes ◽  
Construction Design ◽  
Roof Structure

A new pipe-roof construction method, the steel support cutting pipe method (SSCP), was proposed to improve the construction security and accuracy of pipe jacking as well as underground space usage. The pipe-roof method is one of the underground excavation methods which push multiple steel pipes into the soil, then connect the steel pipes horizontally to form a whole. The proposed structure’s failure mode and force characteristics were determined through theoretical analysis, and then its ultimate bearing capacity and influencing parameters were analyzed through laboratory experiments and numerical simulation. The research results show that the structure’s bearing capacity depends on the steel pipe’s buckling load; the structure’s failure mode is a result of the steel pipe’s buckling. The ultimate bearing capacity of the pipe-roof structure first increases and then decreases with the increase of the steel pipe chord height ratio. The ultimate bearing capacity reaches the maximum when the ratio is 0.33. In addition, the structure’s ultimate bearing capacity is positively related to the steel pipe wall thickness and the pipe section’s length. This can be obtained from the relationship curve showing that the steel pipe wall thickness should be selected according to the engineering requirements and that the pipe section’s length is preferably 2.3 times the diameter of the steel pipe in the construction design.

Micro-Radiography and Tomography for High Resolution NDT of Advanced Materials and Microstructural Components

1990 ◽  
Vol 112 (2) ◽  
pp. 223-226 ◽  
Author(s):  
M. Maisl ◽  
H. Reiter ◽  
P. Ho¨ller
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
High Strength ◽  
Advanced Materials ◽  
Reinforced Composites ◽  
High Resolution Computed Tomography ◽  
Linear Dimensions ◽  
Order Of Magnitude ◽  
Fibre Reinforced Composites

Quality assessment of advanced materials like high strength ceramics and fibre reinforced composites requires detection and characterization of early damage and defects like cracks and pores even with linear dimensions of only 10 μm. Structures of the same size must be distinguishable in components of precision mechanics and electronics. This paper discusses some applications of microfocal X-ray radiography and high resolution computed tomography in nondestructive evaluation of such components. The latter can be looked at as a nondestructive microscopic technique imaging cross sections of an object. Results of investigations using a tomographic unit with a resolution capability of the order of magnitude of 20 μm are presented.

Dynamic Instability and Resonances of Geometrically Imperfect Plates

1997 ◽  
Author(s):  
Germain L. Ostiguy ◽  
Lyne St-Georges
Keyword(s):  
Parametric Resonance ◽  
Dynamic Instability ◽  
Equations Of Motion ◽  
Initial Imperfection ◽  
Temporal Response ◽  
Internal Resonances ◽  
Small Vibration ◽  
Geometric Imperfections ◽  
Linear Behavior ◽  
Initial Geometric Imperfections

Abstract The parametric resonance and other dynamic instabilities of a rectangular plate with initial geometric imperfections acted upon by parametric excitation have been investigated. The temporal equations of motion describing the non-linear behavior of these plates for large oscillations are solved using a direct integration. Results are compared with those obtained from an approximate analytical method. For a structure with a sufficiently large initial imperfection, the soft-spring nature of parametric resonance is confirmed for small vibration amplitudes, followed by a hard-spring behavior for large vibration amplitudes. However, the temporal response of the imperfect structure displays a predominant inward deflection. This phenomenon increases with an augmentation of the imperfection amplitude. Moreover, some resonances not predicted by analytical methods are observed. Besides the possibility of principal parametric resonance, many internal resonances may be observed during a passage through a single parametric resonance.

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