K = 85 MPa√m < KIC = 100 MPa√m
The team compared this value to the fracture toughness:
The team used the following equation to calculate the stress intensity factor: principles of fracture mechanics rj sanford pdf pdf work
a = 2 inches + (2.5 * 10^(-5) inches/cycle * 10,000 cycles) = 4.5 inches
The investigation revealed that the pipeline had been fabricated using a welding process, and that the weld had not been properly heat-treated. As a result, the weld region had a higher yield strength and a lower toughness than the base metal. K = 85 MPa√m < KIC = 100
In a large industrial plant, a critical component, a high-pressure pipeline, failed catastrophically, resulting in significant damage and downtime. The pipeline was made of a high-strength steel alloy, with a wall thickness of 2 inches and an outside diameter of 12 inches. It was designed to operate at pressures up to 1000 psi.
KIC = σ√(πac)
The team recommended that the pipeline be replaced with a new one, fabricated using a improved welding process and inspected regularly using non-destructive evaluation techniques.