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Pipe fracture studies under compliant bending

Fracture studies were carried out on 18 numbers of 219 mm diameter of SA 333 Gr. 6 carbon steel straight pipes and elbows having through-wall crack under four point bending. The investigations have shown that the load carrying capacity of the pipes under finite compliance (fixed end condition) increases when compared to infinite compliance (simply supported condition). The load carrying capacity of the pipes under finite compliance weakly depends on the initial crack angle whereas the load carrying capacity of the pipes under infinite compliance strongly depends on the initial crack angle. The safety margin is quite large particularly with a stiff piping system. This benefit in terms of increase in safety margin from LBB point of view is due to the moment redistribution.

Fracture test set-up on 219 mm OD pipe specimen under infinite compliance

Fracture test set-up on 219 mm OD pipe specimen under infinite compliance

Close-up view of instrumentation

Close-up view of instrumentation

Close-up view of crack tip locations

Close-up view of crack tip locations

Close-up view of crack tip locations

Close-up view of crack tip locations

Close-up view of crack tip locations

Close-up view of crack tip locations

Fracture test set-up on 219 mm OD pipe specimen under finite compliance

Fracture test set-up on 219 mm OD pipe specimen under finite compliance