FATIGUE BREAKDOWN OF ROCKS WHILE DRILLING
Key words: drill bit, fatigue failure, rock, cutting structure, stress cycle, weight on bit.
The article focuses on the history of the study of fatigue breakdown of rocks. The number of cycles in fatigue breakdown of rocks is many hundred thousand times less than that of metals. Fatigue breakdown always occurs while drilling because weight on bit is not sufficient to destroy rocks by a single movement of the bit.