Full scale fatigue testing of original truss members and connections

2012 ◽  
pp. 1420-1427 ◽  
Author(s):  
R Helmerich
Keyword(s):  
Fatigue Testing ◽  
Full Scale

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.

scholarly journals Benefits of sub-component over full-scale blade testing elaborated on a trailing edge bond line design validation

2017 ◽  
Author(s):  
Malo Rosemeier ◽  
Gregor Basters ◽  
Alexandros Antoniou
Keyword(s):  
Structural Reliability ◽  
Fatigue Testing ◽  
Bond Line ◽  
Full Scale ◽  
Testing Time ◽  
Trailing Edge ◽  
Pure Lead ◽  
Component Testing ◽  
Line Design ◽  
Full Scale Testing

Abstract. Wind turbine rotor blades are designed and certified according to the current IEC (2012) and DNV GL AS (2015) standards, which include the final full-scale experiment. The experiment is used to validate the assumptions made in the design models. In this work the drawbacks of traditional static and fatigue full-scale testing are elaborated, i. e. the replication of realistic loading and structural response. Sub-component testing is proposed as a potential method to mitigate some of the drawbacks. Compared to the actual loading that a rotor blade is subjected to under field conditions, the full-scale test loading is subjected to the following simplifications and constraints: First, the full-scale fatigue test is conducted as a cyclic test, where the load time series obtained from aero-servo-elastic simulations are simplified to a damage equivalent load range. Second, the load directions are typically applied solely in two directions, often pure lead-lag and flap-wise directions which are not necessarily the most critical load directions for a particular blade segment. Third, parts of the blade are overloaded by up to 20 % to achieve the target load along the whole span. Fourth, parts of the blade are not tested due to load introduction via load frames. Finally, another downside of a state-of-the-art, uni-axial, resonant, full-scale testing method is that dynamic testing at the eigenfrequencies of today's blades in respect of the first flap-wise mode between 0.4 Hz and 1.0 Hz results in long test times. Testing usually takes several months. In contrast, the sub-component fatigue testing time can be substantially faster than the full-scale blade test since (a) the load can be introduced with higher frequencies which are not constrained by the blade's eigenfrequency, and (b) the stress ratio between the minimum and the maximum stress exposure to which the structure is subjected can be increased to higher, more realistic values. Furthermore, sub-component testing could increase the structural reliability by focusing on the critical areas and replicating the design loads more accurately in the most critical directions. In this work, the comparison of the two testing methods is elaborated by way of example on a trailing edge bond line design.

Full-scale fatigue testing with initial damage as validation of FRP road bridge design

2016 ◽  
Author(s):  
Jan Hiddingh ◽  
Ronald Grefhorst ◽  
Martijn Veltkamp
Keyword(s):  
Structural Material ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Full Scale ◽  
Total Cost Of Ownership ◽  
Reinforced Polymers ◽  
Maintenance Costs ◽  
Total Cost ◽  
Cost Of Ownership ◽  
Positive Experiences

Bridges built in fibre reinforced polymers (FRP) bring the important advantage of low-maintenance costs, thus reducing the total cost of ownership. Various kinds of FRP-constructions have been built hundreds of times in the last decade, the technology is now beyond the stage of infancy. The Province of Groningen has positive experiences with bridges and lock gates built in FRP. For a 8m span lifting bridge for road usage, the province prescribed FRP as the structural material for the deck, and in parallel required additional validation of the material's fatigue resistance through fullscale testing.

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.

Sign in / Sign up

Export Citation Format

Share Document