Research on damage progression of drill string material based on the extended finite element method

Area of Science:

• Materials Science
• Mechanical Engineering
• Fracture Mechanics

Background:

• Drill pipe failures pose significant risks in oil and gas exploration.
• Understanding mesoscale fracture mechanisms is crucial for improving drill pipe integrity.
• Existing macroscopic models may not capture localized failure phenomena.

Purpose of the Study:

• To investigate the fracture mechanism of S135 drill pipes at the mesoscale.
• To analyze crack propagation behavior and its influence on material properties.
• To develop a simulation framework for predicting drill pipe failure.

Main Methods:

• Material characterization of S135 drill pipe using physical, chemical, and scanning electron microscopy.
• Mesoscale grain model creation using Python scripting on the ABAQUS platform.
• Extended Finite Element Method (XFEM) for simulating dynamic crack propagation.
• Mesomechanics homogenization method for analyzing stress and strain distributions.

Main Results:

• A mesoscale grain distribution model of the S135 drill pipe material was successfully established.
• Simulations revealed stress and strain distributions during crack propagation at the grain level.
• Mesoscale analysis indicated the presence of plastic zones and micro-crack propagation, even under macroscopic elastic conditions.
• The study quantified the influence of crack propagation on drill pipe material behavior.

Conclusions:

• The extended finite element method at the mesoscale provides valuable insights into drill pipe fracture mechanisms.
• Localized phenomena like plastic deformation and micro-cracking are critical considerations for drill pipe design and safety.
• This research offers a methodology for detailed stress analysis at crack tips, aiding in failure prediction and prevention.