scholarly journals Influence of Real-Fluid Properties in Modeling Decompression Wave Interacting with Ductile Fracture Propagation

2005 ◽  
Vol 60 (4) ◽  
pp. 711-719 ◽  
Author(s):  
A. Terenzi
Keyword(s):  
Ductile Fracture ◽  
Fracture Propagation ◽  
Real Fluid ◽  
Decompression Wave ◽  
Fluid Properties

Mechanical and Metallurgical Aspects of the Resistance to Ductile Fracture Propagation in the New Generation of Gas Pipelines

2014 ◽  
Author(s):  
Igor Pyshmintsev ◽  
Alexey Gervasyev ◽  
Victor Carretero Olalla ◽  
Roumen Petrov ◽  
Andrey Arabey
Keyword(s):  
Ductile Fracture ◽  
Mechanical Test ◽  
Fracture Propagation ◽  
Rolling Plane ◽  
Full Scale ◽  
Charpy Test ◽  
Line Pipe ◽  
Surface Separation ◽  
Fracture Arrest ◽  
New Generation

The microstructure and fracture behavior of the base metal of different X80 steel line pipe lots from several pipeline projects were analyzed. The resistance of the pipes to ductile fracture propagation was determined by the full-scale burst tests. The high intensity of fracture surface separation (secondary brittle cracks parallel to the rolling plane of the plate) appeared to be the main factor reducing the specific fracture energy of ductile crack propagation. A method for quantitative analysis of microstructure allowing estimation of the steel’s tendency to form separations is proposed. The procedure is based on the EBSD data processing and results in Cleavage Morphology Clustering (CMC) parameter evaluation which correlates with full-scale and laboratory mechanical test results. Two special laboratory mechanical test types utilizing SENT and Charpy test concepts for prediction of ductile fracture arrest/propagation in a pipe were developed and included into Gazprom specifications.

scholarly journals Control of ductile fracture propagation in modern gas pipelines

2019 ◽  
Vol 0 (1) ◽  
pp. 19-29
Author(s):  
V. S. Vakhrusheva ◽  
A. D. Luchkov ◽  
M. V. Pushkarenko
Keyword(s):  
Ductile Fracture ◽  
Fracture Propagation ◽  
Gas Pipelines

Ductile Fracture Control for High Strength Steel Pipelines

2006 ◽  
Author(s):  
Andrea Fonzo ◽  
Andrea Meleddu ◽  
Giuseppe Demofonti ◽  
Michele Tavassi ◽  
Brian Rothwell
Keyword(s):  
Ductile Fracture ◽  
High Strength Steel ◽  
Driving Force ◽  
Empirical Relationship ◽  
Fracture Propagation ◽  
High Strength ◽  
Operating Conditions ◽  
Resistance Force ◽  
Fracture Control ◽  
Material Fracture

The determination of the toughness values required for arresting ductile fracture propagation has been historically based on the use of models whose resulting predictions can be very unreliable when applied to new high strength linepipe materials (≥X100) and/or different operating conditions. In addition, for the modern high strength steels a methodology for determining the material fracture resistance for arresting running shear fracture starting from laboratory data is still lacking. The work here presented (developed within a PRCI sponsored project) deals with the use of CSM’s proprietary PICPRO® Finite Element code to develop methodologies for ductile fracture propagation control in high grade steel pipes. The relationships providing the maximum crack driving force which can be experienced in a pipe operated at known conditions have been determined, for different types of gas. On the other side, an empirical relationship has been found to correlate the critical Crack Tip Opening Angle (CTOA) determined by laboratory testing, to the critical CTOA on pipe (which represents the material fracture propagation resistance) with the aid of devoted simulations of past full-scale burst tests. By comparing Driving Force and Resistance Force, ductile fracture control for high strength steel pipelines can be achieved.

Next Generation Ductile Fracture Arrest Analyses for High Energy Pipelines Based on Detail Coupling of CFD and FEA Approach

2018 ◽  
Author(s):  
K. K. Botros ◽  
E. J. Clavelle ◽  
M. Uddin ◽  
G. Wilkowski ◽  
C. Guan
Keyword(s):  
Ductile Fracture ◽  
Test Data ◽  
Fracture Propagation ◽  
Crack Tip ◽  
Propagation Speed ◽  
High Energy ◽  
Computational Effort ◽  
Pipe Material ◽  
The Past ◽  
Toughness Parameter

Axial ductile fracture propagation and arrest in high energy pipelines has been studied since the early 1970’s with the development of the empirical Battelle Two-Curve (BTC) model. Numerous empirical corrections on the backfill, gas decompression models, and fracture toughness have been proposed over the past decades. While this approach has worked in most cases, the dynamic interaction between the decompression of the fluid in the vicinity of the crack tip and the behaviour of the pipe material as it opens to form flaps behind the crack has been very difficult to solve from a more fundamental approach. The effects of the pressure distribution on the flap inner surface making up the crack-driving force which drives the crack propagation speed has been suggested in the past, but due to intensive computational effort required, it was never realized. The present paper attempts to tackle this problem by employing an iterative solution procedure where the gas pressure field in the vicinity of the crack tip is accurately solved for by computational fluid dynamics (CFD) for a given flap geometry determined from a dynamic FEA model to render a new flap geometry. In this model a cohesive-zone element at the crack tip is employed as a representation of the material toughness parameter. The final outcome is the determination of the cohesive energy in the FEA (as a representation of the material toughness parameter) to match the measured fracture propagation speed for the specific case. A case study was taken from full-scale rupture test data from one of the pipe joints from the Japanese Gas Association (JGA) unbackfilled pipe burst test data conducted in 2004 on the 762 mm O.D., 17.5 mm wall thickness, Gr. 555 MPa (API 5L X80) pipe.

Sign in / Sign up

Export Citation Format

Share Document