A piston, 9 cm in diameter, is used to increase the internal pressure in a cylinder from 0 to 50 MPa. The cylinder, which is made of peak-aged aluminum alloy (yield strength = 500 MPa, Kic = 35 MPaVm), has the following dimensions: length = 20 cm, inner diameter = 9 cm and outer diameter =1 1 cm. The piston-cylinder arrangement suffered a malfunction which caused the cylinder to burst. Post-failure analyses showed the presence of a defect in the form of an elliptical flaw 4.4 mm long at the inner wall, 1.5 mm deep and oriented normal to the hoop stress in the cylinder. Compute the magnitude of the pressure at which the cylinder burst.