Evaluation of the conditions of drill pipes failure during tripping operations

The experimental evaluation of the power criterion for the metal fracture of the reserve and the long operated drill pipes was carried out. The conditions under which, during tripping operations, the failure of explored drill pipes, containing external or internal transverse annular cracks are possible. An interrelation between the depth of critical external or internal transverse annular cracks in drill pipes with the weight of the drilling string is considered, taking into account the influence of dynamic loads during tripping operations. It is shown that internal transverse annular cracks in lowering operating drilling strings at depths of more than 1400 m are more dangerous than external ones, while at depths up to 1400 m, external cross-sectional circular cracks are more dangerous.

Investigation of the Pipe Weld for Brittle Metal Fracture

The article presents the results of studies of artificial strain aging of pipe steels. The effect of deformation aging on the mechanical properties of steel during tensile tests has been determined.

VistaDam: A Physics Based Ductile Fracture Model for Pressurized Pipe Failure

We present VistaDam, a physics-based ductile fracture material model that is tailored to predict failure in thin metal sheets. VistaDam is based on a three invariant plasticity model in which metal fracture is dependent on the combined evolution of the triaxial stresses as well as the third invariant of deviatoric stress. Thus, VistaDam can predict damage due to combined volumetric void growth and shear dilation; which provides VistaDam with a superior capability to describe and predict fracture in a wide range of loading ranges. VistaDam relies on three independent material parameters that can be calibrated from experimental data at different triaxiality. Calibration is achieved through the automated calibration tool VistaCal. The calibrated VistaDam material card can be readily used in explicit FEM packages such as Abaqus and LS-DYNA. In addition, the calibrated VistaDam model can be used as a virtual testing platform that can generate data required by data-driven models such as GISSMO and Johnson-Cook. This process is currently automated within VistaCal’s graphical user interface. VistaDam and VistaCal have been developed for Navy applications and have been deployed successfully to predict pressurized pipes and vessel deformation and fracture under extreme loading conditions.

Effect of ZrO2 Nanomaterials on Wettability and Interfacial Characteristics of Al-19Cu-11Si-2Sn Filler Metal for Low Temperature Al to Cu Dissimilar Brazing

Dissimilar Al 3003 and Cu tubular components were successfully brazed without interface cracking using ZrO2 nanomaterials reinforced with Al-19Cu-11Si-2Sn filler. The filler was initially cast using an induction furnace and processed into ring form for brazing. Al-19Cu-11Si-2Sn filler with coarse CuAl2 and Si phases (43 and 20 μm) were refined to 8 and 4 μm, respectively, after the addition of 0.1 wt. % ZrO2 and shows significant improvement in the mechanical properties. ZrO2 nanomaterials’ induced diffusion controlled growth mechanism is found be the responsible for the refinement of CuAl2 intermetallic and Si particles. The wettability of Al-19Cu-11Si-2Sn-0.1ZrO2 increased to 78.17% on Cu side and 93.19% on the Al side compared from 74.8% and 89.9%, respectively. Increase in the yield strength, ultimate tensile strength, and percentage elongation were noted for the brazed joints. Microstructure of induction brazed joint with 40 kW for 6 seconds using Al-19Cu-11Si-2Sn-0.1ZrO2 filler shows thin interfacial CuAl2 intermetallic compound along the copper side and inter-diffusion region along the aluminum side and their respective mechanism is discussed. The tensile strength of the joints increased with increasing the nanomaterials addition and shows a base metal fracture. Analysis of fractured samples shows the effectiveness of ZrO2 reinforced filler in crack propagation through the filler.