Failure Mechanisms of Critical Marine Connector Bolts

The unexpected failure of critical subsea connector bolts is keeping the oil & gas industry in “stress” because the “root cause” remains unknown. Failures of critical subsea bolts have been occurring for more than a decade now in-spite of replacing more than 10,000 bolts and following quality control (QC) recommendations from industry experts. A few theories have been postulated to explain the phenomenon, which allude to a combination of mechanical stress, environmental and material issues. However, a more thorough understanding is essential. Meanwhile, the logical question emerges: can bolt failures be avoided? To do so, we set to examine some of the key factors such as:

  • Material fatigue;
  • Hydrogen embrittlement;
  • Material hardness;
  • The implications of stress concentration zones;
  • The role of coatings, and
  • The effect of microbiologically influenced corrosion.

In order to understand the failure of bolts, we use a combination of experimental and theoretical means suitable for examining the influence of various parameters under control conditions. In tandem, we employ numerical modelling to test various material factors such as material grade, level of stress, the influence of temperature, material brittleness, and others. Last but not least, we study the electrochemistry of corrosion in parallel with other mechanisms which can be held responsible for the catastrophic failure of marine bolts.

Commencement date: Spring 2018-

Research Team: Mr. Ofer Medlinsky, Dr Constantinos Hadjistassou, Prof. Amir Eliezer

Collaborators: The Corrosion Research Center, Nano-Bio & Advanced Materials; Shamoon College of Engineering, Israel

Publications: Coming soon…