Diego F. B. Sarzosa

Relationship Between J and CTOD in SE(T) and SE(B) Specimens for Stationary and Growing Cracks

Current defect assessment procedures of large engineering structures, including pipeline systems and their welded components such as field girth welds, employ crack growth resistance curves in terms of J-resistance or CTOD-resistance curves. Standardized techniques for crack growth resistance testing of structural steels are based upon laboratory measurements of load-displacement records and adopt two related estimation formulas for fracture toughness values: 1) estimating J from plastic work based on crack mouth opening displacement (CMOD), and 2) determining the CTOD value from first evaluating the plastic component of J using the plastic work defined by the area under the load vs. CMOD curve and then converting it into the corresponding value of plastic CTOD. This work addresses an investigation on the relationship between J and CTOD for three-point SE(B) and clamped SE(T) fracture specimens based upon extensive numerical analyses conducted for crack configurations with varying crack sizes. These analyses include stationary and crack growth plane-strain results to determine J and CTOD for the cracked configurations based on load-displacement records. The numerical computations show strong similarities between the J-CTOD relationship for stationary and growth analysis with important implications for experimental measurements of CTOD-resistance curves. The study provides a body of results which enables establishing accurate relationships between J and CTOD for use in testing protocols for toughness measurements.Copyright

Fracture resistance testing of dissimilar nickel–chromium girth welds for clad line pipes

This work presents an experimental investigation of the ductile tearing properties for the girth weld of a typical C–Mn pipe internally clad with ASTM UNS N06625 Alloy 625 using measured crack growth resistance curves (

Further Insights on the Relationship Between J and CTOD for SE(B) and SE(T) Specimens Including Ductile Crack Propagation

J{-}\Delta a

Evaluation of Ductile Tearing of X-80 Pipeline Girth Welds Using SE(T), SE(B) and C(T) Fracture Specimens

J-Δa and

Effects of specimen geometry and loading mode on crack growth resistance curves of a high-strength pipeline girth weld

\mathrm {CTOD}{-}\Delta a

A numerical investigation of constraint effects in circumferentially cracked pipes and fracture specimens including ductile tearing

CTOD-Δa curves). Here, the material of the external pipe is a typical API 5L Grade X65 pipeline steel whereas the inner clad layer is made of a nickel–chromium corrosion resistant alloy steel. Testing of the girth weld employed side-grooved, clamped SE(T) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance method using a single specimen technique. This experimental characterization provides additional toughness data which serve to evaluate the effectiveness of current procedures in determining accurate experimentally measured R-curves for this class of material, including the effects of weld strength mismatch.