Fatigue Life Measurements and Analysis for Overstrained Tubes with EvacuatorHoles

摘要

Sections of cannon tubes with inner radius of 53, 60, and 78 mm were cycled fromnear zero to 100 to 300 MPa internal pressure until fatigue failure occurred. The failure locations were along 2-mm holes cut through the cannon wall at a 30 deg angle to the tube axis, for the purpose of evacuating combustion gases from the cannon after firing. The cannons had various amount of autofrettage by overstraining including 0, 30, 50, and 100 percent. The amount of overstrain affected both the initiation position of the fatigue crack along the evacuator hole and the measured fatigue life. Increasing the amount of overstrain moved the