Simulations of Ductile Tearing at Large Strains of Biaxially Loaded Pipes

2009 ◽  
Author(s):  
Jacob Dybwad ◽  
Rikard To¨rnqvist ◽  
Erling O̸stby ◽  
Christian Thaulow
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Large Scale ◽  
Full Scale ◽  
Large Strains ◽  
Model Parameters ◽  
Fracture Toughness Test ◽  
Good Correspondence ◽  
Element Modelling ◽  
Ductile Tearing

The purpose of the present paper is to present results from analyses of ductile tearing of biaxially loaded pipes subjected to large scale yielding. The paper deals with three dimensional finite element modelling of pipes with a circumferentially orientated surface crack, where the analyses aim to reproduce the crack propagation behaviour of six full scale bend tests of x-65 seamless pipes with different levels of internal overpressure. The tests were performed as a part of the joint industry project Fracture Control - Offshore Pipelines. Ductile tearing is taken into account by using the Gurson-Tvergaard-Needleman formulation, where calibration of the material model parameters is done by reproducing the fracture toughness test of a SENT-specimen of the same material with finite element modelling. The following simulations of the pipes show a good correspondence with the full scale test results, where both the global response and the ductile tearing from the crack are captured. One important result of the study is that the Gurson-Tvergaard-Needleman parameters that were calibrated against the SENT-specimen could successfully be used for the ductile tearing simulation of the full scale pipes.

Application of Finite Element Modelling in the Qualification of Large Diameter Unbonded Flexible Risers

2002 ◽  
Author(s):  
Wenchao Zhang ◽  
Justin Tuohy
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Oil And Gas ◽  
Large Diameter ◽  
Full Scale ◽  
Flexible Pipe ◽  
Element Modelling ◽  
Norsk Hydro ◽  
Flexible Risers ◽  
Full Scale Testing

Unbonded flexible pipe has a proven track record in the offshore oil and gas industry for more than 20 years. The product is synonymous with the use of floating production systems spanning the water column and connecting subsea structures to facilitate the retrieval of hydrocarbons, provision of water injection systems and the export of processed or semi-processed fluids to main trunk pipelines or onshore. Unbonded Flexible pipe is a technically complex multi-layer structure of helically wound metallic wires and tapes and extruded thermoplastics. In 1996 Wellstream was awarded a major contract for the supply of flexible risers and flowlines as part of the Norsk Hydro Troll Olje Gas Province Development located in 350m water depth 80km west of Bergen. The development consists of two main fields, Troll East (31/3 and 31/6) and Troll West (31/2) which together have an estimated production life in excess of 50 years, making it one of the worlds largest offshore developments. Norsk Hydro is responsible for the development and operation of the production facilities. The scope of supply included 15-inch internal diameter, 213 barg design pressure, dynamic risers for the export of oil and gas from the platform to shore. At contract award, Wellstream was finalising the location of their European Manufacturing site, a facility which would have the capability of manufacturing unbonded flexible pipe with external diameters up to 24-inches. The design, manufacture and qualification of a large diameter oil and gas export riser for service in the Norwegian sector of the North Sea, considered to be one of the most severe environments in the offshore industry, provided unique challenges and attributes. These risers have now been in service for over two year, following an extensive qualification programme. This paper provides an insight into the integrated approach adopted during qualification with the successful application of finite element technology to aid full-scale testing. During a full-scale test program a finite element simulation of a 15 metre long prototype pipe was performed with special emphasis on the evaluation of contact forces between the flexible pipe and a bend limiting structure. The finite element analysis program package ANSYS is chosen for this simulation due to its special feature of contact/target elements. The paper illustrates that the use of Finite Element Modelling is indeed capable of predicting the observed behaviour of prototype risers, which are subjected to a series of dynamic load cases, in a Dynamic Test Rig (DTR). Finally, the paper concludes that focus should now be given to the advantages of using finite element tools that are verified by full scale testing to reduce development costs and schedules.

A Relation between Laboratory and Full-Scale Testing of Polyester/Polyester Composites under Static and Dynamic Load

2007 ◽  
Vol 561-565 ◽  
pp. 725-728
Author(s):  
Pieter Samyn ◽  
Jan Quintelier ◽  
Wim Van Paepegem ◽  
Wim De Waele
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Large Scale ◽  
Fibre Orientation ◽  
Small Scale ◽  
Test Results ◽  
Tribological Behaviour ◽  
Test Configuration ◽  
Element Modelling ◽  
Polyester Composites

The tribological behaviour of a polymer composite is compared during small-scale and large-scale sliding tests and it is observed that test results strongly depend on the fibre orientation and test configuration. Different wear mechanisms are evaluated by optical microscopy and finite element modelling in relation to a real application of polyester/polyester discs as bearing elements.

Finite element modelling of the nonlinear load-slip behaviour of full-scale timber-to-concrete composite T-shaped beams

2018 ◽  
Vol 196 ◽  
pp. 117-126 ◽  
Author(s):  
M. Oudjene ◽  
E.M. Meghlat ◽  
H. Ait-Aider ◽  
P. Lardeur ◽  
M. Khelifa ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Full Scale ◽  
Nonlinear Load ◽  
Element Modelling
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