Effects of Plastic Deformation on Fatigue Life of Superduplex Steel Tube Umbilical

2012 ◽  
Author(s):  
Diego F. S. Burgos ◽  
Luís F. S. Parise ◽  
Rafael G. Savioli ◽  
Gustavo H. B. Donato ◽  
Antonio P. Nascimento Filho ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Fatigue Behavior ◽  
Axial Loading ◽  
Steel Tube ◽  
Fatigue Tests ◽  
Steel Tubes ◽  
Fatigue Data ◽  
Different Levels

This work presents an experimental investigation of the effects of plastic strain on the fatigue behavior of superduplex steel tubes. Fatigue tests using conventional axial loading and a resonant bending setup conducted on 15mm OD tubes made of SAF2507 superduplex steel provides S × N data upon which effects of different levels of plastic strain can be assessed. Despite the inherent scatter in the measured fatigue data, the experiments reveal consistent trends and relatively small effects of plastic strain on fatigue behavior of superduplex steel tubes.

Fatigue Behavior of a 22Cr-20Ni-18Co-Fe Alloy at Elevated Temperatures

1994 ◽  
Vol 116 (1) ◽  
pp. 54-61 ◽  
Author(s):  
T. H. Krukemyer ◽  
A. Fatemi ◽  
R. W. Swindeman
Keyword(s):  
Experimental Investigation ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Frequency Separation ◽  
Isothermal Fatigue ◽  
Deformation Properties ◽  
Fatigue Data ◽  
Haynes Alloy

An experimental investigation was conducted on Haynes Alloy 556 to study the fatigue behavior of the material at elevated temperatures. Fatigue tests were run at constant temperatures ranging from room temperature to 871°C with strain ranges from 0.265 to 1.5 percent resulting in lives between 102 and 106 cycles. Cyclic deformation properties were evaluated based on the fatigue data. Three fatigue life models were evaluated for their ability to predict the isothermal fatigue lives of the material. These included the Ostergren, Frequency Separation and Stress-Strain-Time models. Strengths and weaknesses of each model are discussed based on the experimental results.

Effect of Weld Geometry on the Fatigue Behaviour of Umbilical Super Duplex Stainless Steel Tubes

2017 ◽  
Author(s):  
Hauwa Raji ◽  
Jamie Fletcher Woods
Keyword(s):  
Stainless Steel ◽  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Super Duplex Stainless Steel ◽  
Steel Tubes ◽  
Weld Geometry ◽  
Weld Profile ◽  
Weld Toe ◽  
Toe Angle

The fatigue behavior of welded components is complicated by many factors intrinsic to the nature of welded joints. The mechanical properties of the material, the welding process and position, the type and geometry of the weld and the residual stress distribution across the weld are a few factors affecting fatigue behavior. Published studies [1, 2] have shown that weld geometry is significantly important in determining the fatigue strength of the weld. For a given weld geometry, the fatigue strength is determined by the severity of the stress concentration at the weld toe or at weld defects and by the soundness of the weld metal. The effect of external weld geometry profile on the fatigue behavior of welded small bore super duplex umbilical steel tubes is investigated. Root cause analysis consisting of fractography, metallography and weld profile measurement is carried out on pairs of fatigue failure samples which were tested at the same stress range but failed at significantly different number of cycles. The samples are selected from Technip Umbilicals Ltd (TU) fatigue database. Following the failure analysis, weld geometric profile measurements are performed on fatigue test samples that were prepared for testing. The weld profile was measured in terms of the external weld cap height, weld width and external linear misalignment. Axial fatigue tests are carried out on these samples which are pre-strained before test to simulate the plastic bending cycles typically experienced during the manufacturing and installation processes prior to operational service. The fatigue tests results are interrogated together with the measured geometric data to identify trends and anomalies. Key weld geometric fatigue performance criteria are subsequently identified. For the welded super duplex stainless steel (SDSS) tubes studied, the height of the weld and the weld toe angle provided the best correlation with fatigue life — shorter lives were obtained from specimens with the highest weld aspect ratio (weld height to width) and lowest weld toe angle.

Effect of Roller-Working on Fatigue Strength Improvement of Notched Structural Stainless Steel

2006 ◽  
Vol 306-308 ◽  
pp. 151-156
Author(s):  
Priyo Tri Iswanto ◽  
Shinichi Nishida ◽  
Nobusuke Hattori ◽  
Yuji Kawakami
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Fatigue Limit ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Increase With Increase ◽  
Fatigue Strength Improvement ◽  
Rolled Specimen ◽  
Number Of Cycles

In order to study the effect of plastic deformation on fatigue behaviors of plastically deformed specimen, bending fatigue tests had been performed on notched deformed stainless steel specimens. Also pulsating fatigue tests were done on notched non-deformed specimens to evaluate the influence of mean stress on fatigue behavior of notched non-deformed specimens. The result showed that according to increase of deformation value, the fatigue limits of these specimens also significantly increase. Fatigue limit of rolled specimen does not linearly increase with increase in plastic deformation value. Based on fatigue limit diagram, the effect of compressive residual stress on fatigue limit improvement of stainless steel is higher than that of work-hardening. In case of non-deformed specimen, when the compressive mean stress increases, the fatigue limit and the number of cycles to failure increase. In case of tensile mean stress, this kind of mean stress decreases the fatigue limit.

scholarly journals Isothermal Fatigue Behavior of Sn-Pb Solder Joints

1990 ◽  
Vol 112 (2) ◽  
pp. 94-99 ◽  
Author(s):  
T. S. E. Summers ◽  
J. W. Morris
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Strain Rate ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Load Drop ◽  
Plastic Strain Range ◽  
Double Shear ◽  
Isothermal Fatigue ◽  
Fatigue Data

Isothermal fatigue data were collected for the compositions 5Sn-95Pb, 20Sn-80Pb, 40Sn-60Pb, 50Sn-50Pb and 63Sn-37Pb within the binary Sn-Pb system. All of these compositions are commercially available and include those most commonly used. Because Sn-rich solders are rarely used, they were not investigated here. The fatigue life was defined by a 30 percent load drop. The solders were tested in a double shear configuration joined to copper at 75° C. The displacement rate chosen was 0.01 mm/min, which corresponds to a strain rate of 1.5 × 10−4s−1 for our specimen configuration, over a 10 percent plastic strain range. Additionally, the microstructural changes during fatigue are presented. The various solder compositions studied exhibit strikingly different as-solidified microstructures. These differences are discussed in terms of their effect on the isothermal joint failure mechanism and joint isothermal fatigue life.

scholarly journals INFLUENCE OF CARBON CONTENT ON FATIGUE STRENGTH OF DRAWN STEEL TUBES FOR SMALL ONCE-THROUGH BOILER

2012 ◽  
Vol 06 ◽  
pp. 361-366
Author(s):  
DAISUKE YONEKURA ◽  
YUTA FUJIE ◽  
RI-ICHI MURAKAMI ◽  
YUKIHIRO TOKUNAGA
Keyword(s):  
Heat Treatment ◽  
Fatigue Strength ◽  
Carbon Content ◽  
Steel Tube ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Post Heat Treatment ◽  
Steel Tubes ◽  
Heat Treated ◽  
The Difference

Tension-tension fatigue tests were performed to examine the influence of carbon content on the fatigue properties of drawn specific steel tube (STB340) with/without post heat treatment for small once-through boiler. Two different carbon content steel tubes, C =0.06 and 0.12% were prepared. The as-received, as-drawn and post drawing heat treated series for each carbon content tube were prepared for fatigue test. The hardness, grain size and residual stress were measured for each series. As a result, the fatigue strength of as-received and as-drawn series showed a small difference between C =0.06 and 0.12% specimens. However, the post drawing heat treatment series showed obvious difference in the fatigue strength. The fatigue strength of higher carbon content tubes significantly decreased by the post drawing heat treatment, whereas the decrease of fatigue strength was little for lower carbon content heat treated tubes. The difference of fatigue strength was mainly caused by the degree of relaxation of work hardening by post heat treatment.

scholarly journals Axial Loading Behaviour of Self-Compacting Concrete-Filled Thin-Walled Steel Tubular Stub Columns

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yunyang Wang ◽  
Lei Xiao ◽  
Chu Jiang ◽  
Yandong Jia ◽  
Guang Yang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Ultimate Load ◽  
Local Buckling ◽  
Axial Loading ◽  
Steel Tube ◽  
Self Compacting Concrete ◽  
Steel Tubes ◽  
Thin Walled ◽  
Stub Columns ◽  
Versus Strain

This paper presents an experimental investigation on the mechanical behaviour of self-compacting concrete-filled thin-walled steel tubular (SCCFTST) stub columns loaded in axial compression to failure. Four specimens were tested to study the effect of diameter to wall thickness (D/t) ratios on the ultimate load, failure modes, and ductility of the columns. Confinement of the steel tube to concrete was also addressed. The failure modes, load versus displacement curves, and load versus strain curves were examined in detail. The experimental results showed that the ultimate state is reached when severe local buckling and rupture occurred on the steel tubes, and the concrete near the rupture has been crushed. The columns with larger D/t ratios appeared more local buckling, and its location is more close to the end of the columns. The SCCFTST stub columns with smaller D/t ratios show higher ultimate load and better ductility, and the steel tubes can exert higher confinement to the concrete.

scholarly journals Experimental Investigation of Flexural Behavior of Ultra-High-Performance Concrete with Coarse Aggregate-Filled Steel Tubes

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6354
Author(s):  
Fanghong Wu ◽  
Yanqin Zeng ◽  
Ben Li ◽  
Xuetao Lyu
Keyword(s):  
Experimental Investigation ◽  
High Performance ◽  
Coarse Aggregate ◽  
High Performance Concrete ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Flexural Stiffness ◽  
Flexural Capacity ◽  
Ultra High Performance Concrete ◽  
Steel Tubes

This paper presents an experimental investigation of flexural behavior of circular ultra-high-performance concrete with coarse aggregate (CA-UHPC)-filled steel tubes (CA-UHPCFSTs). A total of seven flexural members were tested under a four-point bending load. The failure modes, overall deflection curves, moment-versus-curvature relationships, moment-versus-strain curves, strain distribution curves, ductility, flexural stiffness and ultimate flexural capacity were evaluated. The results indicate that the CA-UHPCFSTs under bending behaved in a good ductile manner. The CA-UHPC strength has a limited effect on the ultimate flexural capacity, while the addition of steel fiber can improve the ultimate flexural capacity. Increasing the steel tube thickness leads to higher flexural stiffness and ultimate flexural capacity. There is a significant confinement effect between the steel tube and the CA-UHPC core in the compressive zone and centroidal plane after the specimen enters the elastic-plastic stage, while the confinement effect in the tensile zone is minimal. Moreover, the measured flexural stiffness and ultimate flexural capacity were compared with the predictions using various design specifications. Two empirical formulas for calculating the initial and serviceability-level flexural stiffness of CA-UHPCFSTs are developed. Further research is required to propose the accurate design formula for the ultimate flexural capacity of CA-UHPCFSTs.

Thermal Fatigue of a Nickel-Base Alloy

1965 ◽  
Vol 87 (1) ◽  
pp. 237-244 ◽  
Author(s):  
A. E. Carden
Keyword(s):  
Plastic Strain ◽  
Thermal Fatigue ◽  
Strain Energy ◽  
Thermal Stresses ◽  
Base Alloy ◽  
Fatigue Tests ◽  
Fatigue Data ◽  
Plastic Strain Energy ◽  
Nickel Base ◽  
Good Agreement

The results of conventional (Coffin-type) thermal-fatigue tests of Hastelloy N are reported. The plastic-strains induced by thermal stresses ranged from a hundred micro-units to more than ten-thousand microunits and correlated well with fatigue life. The slope of the plastic-strain fatigue relationship differs from the conventional slope of minus one half being about −0.9. The thermal-fatigue data are in good agreement with the isothermal (1300 and 1500 deg F) strain fatigue data available on this alloy. The same plastic-strain criterion for failure describes the results of tests where plastic flow is produced by yielding and a combination of yielding and stress relaxation. The plastic-strain energy per cycle versus life suggests that a constant plastic work to failure exists for this alloy. The implications of such a criterion are discussed.

Effect of Reeling on Small Umbilical Tubing Fatigue

2008 ◽  
Author(s):  
Jaime Buitrago ◽  
Krassimir Doynov ◽  
Allen Fox
Keyword(s):  
Plastic Strain ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Experimental Methodology ◽  
Experimental Program ◽  
Duplex Steel ◽  
Fatigue Data ◽  
Steel Tubing ◽  
Current Design ◽  
Pressurized Fluids

Umbilicals use steel tubing of different sizes to carry various pressurized fluids. During manufacturing, transportation and installation of the umbilicals, the tubing is subjected to reeling and unreeling operations, resulting in a cumulative amount of plastic strain. The amount of strain varies with different cross-section designs and umbilical manufacturers. This plastic strain may limit the fatigue performance of the tubing in dynamic umbilicals, thereby limiting the number of reeling operations of umbilicals in deepwater. A previous paper presented a novel experimental methodology to simulate reeling and its effect on the fatigue of 57.6-mm ID × 3.4-mm WT made of super duplex steel. Results indicated that reeling can significantly degrade the fatigue performance of the welded tubing as the cumulative reeling strain increases up to 20%. This paper discusses an experimental program aimed at assessing the size effect on fatigue of reeled tubing. Ten 10 additional fatigue tests were conducted with 12.6-mm ID × 1.46-mm WT tubing reeled to 20% strain. Results indicate that the smaller tubing, once reeled to 20%, its fatigue performance degrades to the same level as that of the larger tubing. However, the combined fatigue data do not support current design criteria DnV-RP-C203. Therefore, given the uncertainty of all of the variables involved, fatigue qualification for specific applications is considered necessary.

Fatigue Behavior of GeO2-SiO2 Glasses

1998 ◽  
Vol 531 ◽  
Author(s):  
Suresh T. Gulati ◽  
John D. Helfinstine
Keyword(s):  
Thermal Expansion ◽  
Physical Properties ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Binary Oxide ◽  
Oxide Glasses ◽  
Mechanical Reliability ◽  
Four Point Bending ◽  
Fatigue Data

AbstractThe fatigue behavior of binary oxide glasses in the germania-silica system is interesting since it influences the long-term mechanical reliability of products made of these glasses. Dynamic fatigue tests were carried out in four-point bending in 100% RH using tumble abraded rods. The fatigue data were obtained as a function of GeO2 content which ranged from 0 to 24 mole %. In addition, other physical properties of these glasses, such as the thermal expansion coefficient, were measured as a function of GeO2 content. The results of these tests and analyses are highlighted in this paper.

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