Multi-component friction testing of full-scale drill pipe specimen

Aluminum alloys are among the most promising materials for manufacture of drill pipes for deepwater and ultra-deepwater drilling in corrosive environment. Aluminum drill pipes are made with steel tool-joints to increase the number of connection makings-and-breakings. One of the major concerns of aluminum drill pipe operation in deepwater complex profile wells is the fatigue of their connection. This paper presents the results of study of fatigue properties of aluminum alloy 1953T1 Light Alloy Drill Pipes of Improved Dependability (LAIDP) 147×13 mm that are most extensively used in Russia. During assembly, the pin and box of steel tool-joint are heated and screwed on the tubular ends. After cooling, this assembly provides a reliable permanent connection. The study includes experimental determination of the S-N curve of small-scale specimens of aluminum tubular, FEA of the connection with the SCF determined and fatigue testing of the full-scale LAIDP connection. FEA is based on 3D model. The material properties of tubular are modeled as elastic-plastic. The distribution of hot-assembly stresses is considered in detail. Alternating bending load is applied by several semi-cycles. The results of analysis of Stress Concentration Factor (SCF) at various axial loads, bending moment ranges, friction factors of contact surfaces and interference of connection are given. Full-scale fatigue testing of connection specimen is carried out to verify the results of analysis.

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Full Scale VIV Response Measurements of a Drill Pipe in Gulf of Mexico Loop Currents

Volume 5: Materials Technology; CFD and VIV ◽

10.1115/omae2008-57610 ◽

2008 ◽

Cited By ~ 2

Author(s):

Pierre Beynet ◽

Roy Shilling ◽

Mike Campbell ◽

Elizabeth Tellier ◽

Hugh Howells

Keyword(s):

Gulf Of Mexico ◽

Drill Pipe ◽

Cross Flow ◽

Surface Current ◽

Acoustic Doppler Current Profiler ◽

Full Scale ◽

Loop Current ◽

Loop Currents ◽

Set Up ◽

Current Loading

In September 2004 BP retrieved a Gulf of Mexico drilling riser due to excessive loop currents. Whilst waiting for the currents to diminish an impromptu full scale riser Vortex Induced Vibrations (VIV) test was carried out using the drilling riser standalone monitoring system. A 6-5/8 inch drill pipe was instrumented and deployed under the drilling vessel to a depth of 1,000ft. The drilling vessel drift was varied relative to the loop current to produce a range of current profiles and surface current speeds. Current loading along the length of the drill pipe was measured using the on-board acoustic doppler current profiler (ADCP). The paper describes the test set-up and measured VIV response. It includes observations of cross flow VIV, in-line VIV and additional response at higher frequencies not currently predicted with industry VIV analysis tools.

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Experimental and Numerical Evaluations of Aluminum Drill Pipes Under Cyclic Loads

Volume 3: Safety and Reliability; Materials Technology; Douglas Faulkner Symposium on Reliability and Ultimate Strength of Marine Structures ◽

10.1115/omae2006-92160 ◽

2006 ◽

Author(s):

Marcelo Igor Lourenc¸o ◽

Theodoro A. Netto ◽

Neilon S. Silva ◽

Paulo Emi´lio Valada˜o de Miranda ◽

Joa˜o Carloes Ribeiro Pla´cido

Keyword(s):

Drill Pipe ◽

Fatigue Tests ◽

Full Scale ◽

Experimental Program ◽

Small Scale ◽

Strain Stress ◽

Drill Pipes ◽

Aluminum Pipe ◽

Tool Joint ◽

Joint Assembly

Experimental program and numerical analyses were carried out to investigate the fatigue mechanisms of aluminum drill pipes designed and manufactured in compliance with ISO 15546. Material mechanical properties, including S-N curve, were determined through small-scale tests on specimens cut from actual drill pipes. Full-scale experiments were also performed in laboratory. Initially, the tool-joint assembly procedure was actually performed to monitor the resulting strain/stress level in selected points of the aluminum pipe. Three full-scale aluminum drill pipe specimens were then fatigue tested under combined cyclic bending and constant axial tension. In parallel, a finite element model of the tool-joint region, where two drill pipe specimens failed in the fatigue tests, was developed. The model was first used to reproduce the tool-joint assembly. Then, the physical experiments were simulated numerically in order to obtain the actual stress distribution in this region. Good correlation between full-scale and small-scale fatigue tests was obtained by adjusting the strain/stress levels monitored in the full-scale tests in light of the numerical simulations.

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Relation of Statistically Significant, Abnormal, and Typical WAIS-R VIQ-PIQ Discrepancies to Full Scale IQs

European Journal of Psychological Assessment ◽

10.1027//1015-5759.16.2.107 ◽

2000 ◽

Vol 16 (2) ◽

pp. 107-114 ◽

Cited By ~ 3

Author(s):

Louis M. Hsu ◽

Judy Hayman ◽

Judith Koch ◽

Debbie Mandell

Keyword(s):

Graphical Method ◽

The United States ◽

Full Scale ◽

True Score ◽

Absolute Value ◽

Normative Population ◽

The Us ◽

The Mean ◽

And Performance ◽

Quadratic Models

Summary: In the United States' normative population for the WAIS-R, differences (Ds) between persons' verbal and performance IQs (VIQs and PIQs) tend to increase with an increase in full scale IQs (FSIQs). This suggests that norm-referenced interpretations of Ds should take FSIQs into account. Two new graphs are presented to facilitate this type of interpretation. One of these graphs estimates the mean of absolute values of D (called typical D) at each FSIQ level of the US normative population. The other graph estimates the absolute value of D that is exceeded only 5% of the time (called abnormal D) at each FSIQ level of this population. A graph for the identification of conventional “statistically significant Ds” (also called “reliable Ds”) is also presented. A reliable D is defined in the context of classical true score theory as an absolute D that is unlikely (p < .05) to be exceeded by a person whose true VIQ and PIQ are equal. As conventionally defined reliable Ds do not depend on the FSIQ. The graphs of typical and abnormal Ds are based on quadratic models of the relation of sizes of Ds to FSIQs. These models are generalizations of models described in Hsu (1996) . The new graphical method of identifying Abnormal Ds is compared to the conventional Payne-Jones method of identifying these Ds. Implications of the three juxtaposed graphs for the interpretation of VIQ-PIQ differences are discussed.

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A Modification of the Payne-Jones Method of Identifying Abnormal Differences in WISC-R Performance and Verbal IQ's

European Journal of Psychological Assessment ◽

10.1027/1015-5759.12.1.27 ◽

1996 ◽

Vol 12 (1) ◽

pp. 27-32 ◽

Cited By ~ 1

Author(s):

Louis M. Hsu

Keyword(s):

Full Scale ◽

True Score ◽

Verbal Iq ◽

Score Difference ◽

The Difference ◽

And Performance

The difference (D) between a person's Verbal IQ (VIQ) and Performance IQ (PIQ) has for some time been considered clinically meaningful ( Kaufman, 1976 , 1979 ; Matarazzo, 1990 , 1991 ; Matarazzo & Herman, 1985 ; Sattler, 1982 ; Wechsler, 1984 ). Particularly useful is information about the degree to which a difference (D) between scores is “abnormal” (i.e., deviant in a standardization group) as opposed to simply “reliable” (i.e., indicative of a true score difference) ( Mittenberg, Thompson, & Schwartz, 1991 ; Silverstein, 1981 ; Payne & Jones, 1957 ). Payne and Jones (1957) proposed a formula to identify “abnormal” differences, which has been used extensively in the literature, and which has generally yielded good approximations to empirically determined “abnormal” differences ( Silverstein, 1985 ; Matarazzo & Herman, 1985 ). However applications of this formula have not taken into account the dependence (demonstrated by Kaufman, 1976 , 1979 , and Matarazzo & Herman, 1985 ) of Ds on Full Scale IQs (FSIQs). This has led to overestimation of “abnormality” of Ds of high FSIQ children, and underestimation of “abnormality” of Ds of low FSIQ children. This article presents a formula for identification of abnormal WISC-R Ds, which overcomes these problems, by explicitly taking into account the dependence of Ds on FSIQs.

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