Constraint analysis of defects in strength mismatched girth welds of (pressurized) pipe and Curved Wide Plate tensile test specimens

Abstract

Please cite this article as: Verstraete, M.A., De Waele, W., Denys, R.M., Van Minnebruggen, K., Hertelé, S., Constraint analysis of defects in strength mismatched girth welds of (pressurized) pipe and curved wide plate tensile test specimens, Engineering Fracture Mechanics (2014), doi: http://dx.doi.org/10. 1016/j.engfracmech.2014.07.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Curved Wide Plate (CWP) specimens are often considered to evaluate the tensile strain capacity of girth weld defected pipelines. However, to date no comparison has been made between the constraint in CWP and (pressurized) pipe specimens. This paper reports on the evaluation of the constraint through three dimensional finite element simulations. At first, it is observed that the internal pressure marginally increases the out-of-plane constraint. Second, the CWP specimens appear to closely represent the constraint in pipe specimens for homogeneous as well as strength mismatched situations. CWP specimens become increasingly conservative to pipe specimens with increasing defect dimensions. Constraint analysis of defects in strength mismatchedKeywords: (to be selected from list made available by Elsevier)Constraint effects J-integral Plasticity

Numerical study on the strain capacity of girth-welded X80 grade pipes

“…Therefore, it is unrealistic to conduct a large number of tests accounting for all these factors, and the method of combining numerical simulations and experiments has become a good auxiliary research method. Hertel e et al (Hertel e et al, 2013(Hertel e et al, , 2014Verstraete et al, 2014), confirmed that the CWP specimens seem to be a good representative of the constraints in pipe specimens in the case of mismatched welding. They performed a large series of finite element analysis (FEA) simulations and tests of CWPs to quantify the effect of pipe steel heterogeneity on strain capacity and proposed a new strain capacity equation.…”

Comparison of girth weld tearing resistance obtained from Curved Wide Plate and Single Edge Notch Tensile testing

“…In literature, several (numerical) studies indicate that the constraint in SENT specimens is comparable to pipe specimens [14,50]. Additionally considering the previously published correspondence in constraint between pipe and wide plate specimens [17], it was therefore expected for wide plate and SENT specimens to experience a similar constraint. A closer look to the published literature on SENT testing shows however that the correspondence in constraint is primarily observed for (extremely) shallow notch depths (typically a 0 /W = 0.1).…”

“…For the welded specimens, the initial notch has been located at the weld metal center (WMC) line. Since the relative crack depth range of R-curve scatter band in terms of CTOD is known to significantly alter the constraint both in CWP and SENT tests [17,20,21], specimens of nominally equal crack depth are compared. Focusing on the medium scale tests, so-called medium wide plate (MWP) specimens with a reduced width of 150 mm were selected over the traditionally considered 300 mm wide Curved Wide Plate (CWP) specimens.…”

“…pressurized pipelines). Both the SENT and CWP tests are known to be (limitedly) conservative compared to (pressurized) pipes [7,16,17]. However, there is an ongoing debate on the constraint difference between both tests [18,19].…”