Deformation Measurements on Full-Scale Fracture Tests of Pre-Cracked Tubular Joints

2003 ◽  
Author(s):  
Bijan Talei-Faz ◽  
Feargal P. Brennan ◽  
Stuart Robson
Keyword(s):  
Large Scale ◽  
Fatigue Testing ◽  
Three Dimensional ◽  
Steel Structures ◽  
High Strength ◽  
Static Strength ◽  
Full Scale ◽  
Structural Testing ◽  
Tubular Joints ◽  
Large Steel

A series of six static strength destructive tests were performed on full-scale pre-cracked tubular welded T-joints manufactured from a high strength weldable steel used in the construction of offshore Jack-Up platforms. All specimens had at least one through-thickness fatigue crack at the weld toe, from a previous fatigue-testing programme. The tests were aimed at analysing the residual static strength of the cracked members. As destructive tests are costly to perform, every effort was made to maximise the data collected. This included the use of a novel photogrammetric technique to provide three-dimensional measurement in real time of the deformation in the vicinity of the brace-chord intersection. The technique has been used for large-scale structural testing in a number of civil and aerospace applications, but to the author’s knowledge this is the first time that it has been employed for the full-scale mechanical testing of large steel structures. This paper describes the details of the photogrammetric technique applied to the large steel specimens which were loaded to failure, resulting in the total separation of the intersecting members. It is hoped that the technique can be used to generate information which can be used in conjunction with finite element or other numerical analyses to increase the accuracy and reliability of modelling cracked tubular joints.

Use of DNVGL-RP-C203 for Determining the Fatigue Capacity of Connectors

2021 ◽  
Author(s):  
Anthony Muff ◽  
Anders Wormsen ◽  
Torfinn Hørte ◽  
Arne Fjeldstad ◽  
Per Osen ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Experimental Testing ◽  
High Strength ◽  
Element Model ◽  
Fatigue Analysis ◽  
Full Scale ◽  
The Finite Element Model

Abstract Guidance for determining a S-N based fatigue capacity (safe life design) for preloaded connectors is included in Section 5.4 of the 2019 edition of DNVGL-RP-C203 (C203-2019). This section includes guidance on the finite element model representation, finite element based fatigue analysis and determination of the connector design fatigue capacity by use of one of the following methods: Method 1 by FEA based fatigue analysis, Method 2 by FEA based fatigue analysis and experimental testing and Method 3 by full-scale connector fatigue testing. The FEA based fatigue analysis makes use of Appendix D.2 in C203-2019 (“S-N curves for high strength steel applications for subsea”). Practical use of Section 5.4 is illustrated with a case study of a fatigue tested wellhead profile connector segment test. Further developments of Section 5.4 of C203-2019 are proposed. This included acceptance criteria for use of a segment test to validate the FEA based fatigue analysis of a full-scale preloaded connector.

Cost Effective Fabrication of Large Diameter High Strength Titanium Catenary Riser

2002 ◽  
Author(s):  
Agnes Marie Horn ◽  
Mons Hauge ◽  
Per-Arne Ro̸stadsand ◽  
Bjarne Bjo̸rnbakk ◽  
Peer Dahlberg ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Large Diameter ◽  
High Strength ◽  
Cost Effective ◽  
Full Scale ◽  
Scale Production ◽  
Wear Properties ◽  
Field Development ◽  
Main Challenge

A large diameter high strength titanium free-hanging catenary riser was evaluated by the Demo 2000 Ti-Rise project, from initiative of the Kristin Field development license. In order to reduce the uncertainties related to the schedule, cost, and special technical issues identified in the work related to a similar riser for future installation on the A˚sgard B semi-submersible platform, a fabrication qualification of a full scale riser in titanium was run. Several full-scale production girth welds were made in an in-situ fabrication environment. The welding was performed on extruded titanium grade 23 (ASTM) pipes with an ID of 25.5″) and wall thickness of 30 mm. The main challenge was to develop a highly productive TIG orbital welding procedure, which produced welds with as low pore content as possible. It is well known that sub-surface pores often are initiation sits for fatigue cracks in high strength titanium welds. This paper describes how a greatly improved productivity was obtained in combination with a high weld quality. NDT procedures were developed whit the main on the reliability to detect and locate possible sub-surface weld defects, volumetric defects such as pores and tungsten particles and planar defects such as lack of fusion. The results from the actual Non Destructive Testing (NDT), the mechanical testing, and the fatigue testing of the subjected welds are presented. The response of the catenary is optimised by varied distribution of weight coating along the riser’s length. A satisfactory weight coating with sufficient strength, bond strength, and wear properties was developed and qualified. The riser is planned to be fabricated from extruded titanium pipes, welded together onshore to one continuous piece. The field coating is added and the riser is loaded into the sea and towed offshore and installed.

Hybrid Design Concept Using High-Strength Cast Steel Inserts for Tubular Joints of Offshore Structures

1998 ◽  
Vol 120 (1) ◽  
pp. 10-19 ◽  
Author(s):  
C. M. Sonsino ◽  
R. Umbach
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
Large Scale ◽  
Fatigue Behavior ◽  
Cast Steel ◽  
High Strength ◽  
Offshore Structures ◽  
Fine Grained ◽  
Tubular Joints ◽  
Medium Strength

In a joint project of a German working group supported by the ECSC and the Studiengesellschaft fu¨r Stahlanwendung e.V., the fatigue behavior of large-scale hybrid tubular joints with inserts manufactured from the high-strength cast steel GS-12 MnMo 7 4 welded into tubular members formed from the fine-grained steel StE 500 were compared to the behavior of large-scale welded tubular joints. The latter were made from medium-strength fine-grained steel StE 355 and high-strength StE 690. In addition, data from hybrid joints with cast steel inserts of medium-strength GS-8 Mn 7 welded into StE 355 tubulars is available for comparison. The tests were carried out under variable amplitude loading in artificial seawater. The results were evaluated for the failure criteria fatigue life to crack initiation (a = 1 mm) and through crack. With medium-strength (Rp0.2 > 355 N/mm2) hybrid tubulars, where by the use of cast steel inserts the welds were removed into areas of lower stress concentration, fatigue lives higher than a factor of 100 were achieved compared to the welded nodes, even those made from StE 690. However, by the use of high-strength (Rp0.2 > 500 N/mm2) cast steel inserts and tubular members of corresponding strength, the fatigue life to crack initiation was improved by a factor of two despite a thickness reduction compared to the medium-strength design. Post-weld treatments of the welded tubulars without cast steel inserts like shot-peening, TIG-dressing, or their combination resulted only in a slight increase of fatigue life. The results of this investigation do not only show how to improve the fatigue life by a new design using cast steel inserts, but indicate also how to revise design codes from the point of damage calculation (damage sum of 0.50 for welded nodes and 0.25 for cast steel inserts instead of the conventional value of 1.00), as well as consideration of fatigue life to initiation of a technically detectable crack with a defined depth e.g., a = 1 mm.

Experimental and numerical study of CFRP reinforced steel beams

2020 ◽  
pp. 147509022096026
Author(s):  
Minos E Kypriadis ◽  
Elias P Bilalis ◽  
Nicholas G Tsouvalis
Keyword(s):  
Large Scale ◽  
Numerical Study ◽  
Load Capacity ◽  
Steel Structures ◽  
High Strength ◽  
Maximum Load ◽  
Steel Beams ◽  
High Fatigue ◽  
Reinforced Steel ◽  
Large Scale Tests

The use of composite materials patches for the reinforcement of steel structures attracts particular interest. Due to their high strength, light weight, and high fatigue and corrosion resistance, composite patches represent a versatile reinforcement solution. In this paper, the reinforcement of steel beams with CFRP patches is examined. Large scale tests of “H” and “square hollow” cross section steel beams are conducted. The beams are reinforced with CFRP patches, investigating the effect of the thickness and the length of the patch, and the type of the cohesive joint. All reinforced specimens showed increase of their stiffness and their maximum load capacity. Furthermore, advanced finite element models are developed for the simulation of the mechanical behavior of the reinforced steel beams. FE results relate very well to the experimental ones for most of the measured magnitudes, thus verifying the reliability of the developed models in estimating stiffness, yield load and maximum load capacity of the beams.

Residual Stress Prediction and Relaxation in Welded Tubular Joints under Constant Cyclic Loading

2006 ◽  
Vol 524-525 ◽  
pp. 323-330 ◽  
Author(s):  
Zuheir Barsoum
Keyword(s):  
Thermal Analysis ◽  
Residual Stress ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Three Dimensional ◽  
Hole Drilling ◽  
Moving Heat Source ◽  
Tubular Joints ◽  
Stress Prediction ◽  
Tubular Joint

In this paper three-dimensional welding simulations were carried out in FE software ANSYS in order to predict transient temperatures and the residual stresses in a three pass welded tubular joints. The thermal analysis and the moving heat source were verified with temperature measurements and the computed residual stresses were verified with hole drilling measurements. Then residual stress relaxation analyses were carried out on the tubular structure, with similar load cases as in earlier fatigue testing on the same tubular joint structures.

Characteristics of High Temperature Tensile Properties and Residual Stresses in Welded Joints of the SM570-TMCP Steel

2007 ◽  
Vol 353-358 ◽  
pp. 527-532 ◽  
Author(s):  
Chin Hyung Lee ◽  
H.C. Park ◽  
Gab Chul Jang ◽  
J.H. Lee ◽  
Kyong Ho Chang
Keyword(s):  
High Temperature ◽  
Residual Stresses ◽  
Tensile Properties ◽  
Welded Joints ◽  
Three Dimensional ◽  
Control Process ◽  
Steel Structures ◽  
High Strength ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

TMCP steels produced by thermo-mechanical control process are now spot lighted due to the excellent combinations of strength, toughness and weldability. Recently, in Korea, high strength SM570-TMCP steel whose tensile strength is 600MPa has been developed and applied to steel structures due to its excellent nature. But, for the application of the TMCP steel to steel structures, it is necessary to elucidate not only the material characteristics but the mechanical characteristics of welded joints. In this study, high temperature tensile properties of the SM570-TMCP steel were investigated through the elevated temperature tensile test and the characteristics of residual stresses in welded joints of the TMCP steel were studied through the three-dimensional (3-D) thermal elastic-plastic finite element (FE) analysis on the basis of mechanical properties at high temperatures obtained from the experiment. The results are then compared with the conventional quenched and tempered high strength SM570 steel.

scholarly journals Extraordinary tensile strength and ductility of scalable nanoporous graphene

2019 ◽  
Vol 5 (2) ◽  
pp. eaat6951 ◽  
Author(s):  
Hamzeh Kashani ◽  
Yoshikazu Ito ◽  
Jiuhui Han ◽  
Pan Liu ◽  
Mingwei Chen
Keyword(s):  
Tensile Strength ◽  
Large Scale ◽  
Carbon Materials ◽  
Three Dimensional ◽  
High Strength ◽  
Graphene Sheets ◽  
Nanoporous Graphene ◽  
Flaw Sensitivity ◽  
Relationship Of ◽  
Strength And Ductility

While the compressive strength-density scaling relationship of ultralight cellular graphene materials has been extensively investigated, high tensile strength and ductility have not been realized in the theoretically strongest carbon materials because of high flaw sensitivity under tension and weak van der Waals interplanar bonding between graphene sheets. In this study, we report that large-scale ultralight nanoporous graphene with three-dimensional bicontinuous nanoarchitecture shows orders of magnitude higher strength and elastic modulus than all reported ultralight carbon materials under both compression and tension. The high-strength nanoporous graphene also exhibits excellent tensile ductility and work hardening, which are comparable to well-designed metamaterials but until now had not been realized in ultralight cellular materials. The excellent mechanical properties of the nanoporous graphene benefit from seamless graphene sheets in the bicontinuous nanoporosity that effectively preserves the intrinsic strength of atomically thick graphene in the three-dimensional cellular nanoarchitecture.

Virtual Demonstration Tests of Large-Scale and Complex Artifacts Using an Open Source Parallel CAE System, ADVENTURE

2006 ◽  
Vol 110 ◽  
pp. 133-142 ◽  
Author(s):  
Shinobu Yoshimura
Keyword(s):  
Open Source ◽  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
General Purpose ◽  
Full Scale ◽  
Grid Environments ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Cae System

The ADVENTURE project started as one of the research projects in the "Computational Science & Engineering" field selected for the "Research for the Future" Program sponsored by the Japan Society for the Promotion of Science during 1997-2002. Since March 2002, the project has continued as an independent project. In the project we have been developing an advanced general-purpose computational mechanics system, named ADVENTURE, running in various kinds of parallel and ditributed environments. The system is designed to be able to analyze a three-dimensional finite element model of arbitrary shape with 10-100 million DOFs mesh, and additionally to enable parametric and non-parametric shape optimization. The first version of the system has been released from the project website as open source software since March, 2002. 2,049 registered users in academia and industries have downloaded 12,827 modules and been using them, while one company has developed and released its commercial version named ADVENTUREcluster. The ADVENTURE system has been successfully implemented in various types of parallel and distributed environments including PC clusters, massively parallel processers such as Hitachi SR8000/MPP and the Earth Simulator, and Grid environments such as ITBL (IT-based Laboratory). The system has been successfully applied to solve various real world problems such as response of a full scale nuclear pressure vessel model and thermoelastic deformation of full scale electric mounting board of a mobile PC.

Residual static strength of high strength steel cracked tubular joints

2004 ◽  
Vol 17 (3-4) ◽  
pp. 291-309 ◽  
Author(s):  
B. Talei-Faz ◽  
F.P. Brennan ◽  
W.D. Dover
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Static Strength ◽  
Tubular Joints
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