QUESTION 15 A company that supplies materials undertakes a polish before delivery. This removes any scratch greater than 1mm from the surface. If you require a plate 1 92 cm wide made from an Aluminium alloy (7075), with K1c-24 5 MPa m0.5, what is the maximum stress the material can undergo before catastrophic brittle failure would occur? Give you answer in MPa, to 3 significant figures and do not include the units in your answer

39)A tensile test specimen has a gage length=3.0 inches and a diameter=  .75 inches. Yielding occurs at a load of 38000lbs. The corresponding gage length=3.0103 inches (neglect the .0.2% yield point). The maximum load of 54000lbs is reached at a gage length =3.453 inches. If fracture occurs at a gage length of 3.873inches, determine the percent elongation at fracture (Round to the nearest whole %)

At operating stress of 420MPa, the number of cycles to fail a specimen is 65 cycles. At operating stress of 360MPa, the number of cycles to fail the specimen is 390 cycles, and at operating stress of 130MPa, the number of cycles to fail the specimen is 11,900 cycles. A test sequence as follows is designed: first, operating stress of 420MPa for 7 cycles, second, operating stress of 360MPa for 65 cycles, and third, operating stress of 130MPa for 325 cycles. Determine at what number of cycle and which operating stress level the specimen would be expected to fail if the above sequence is repeated.

1) Large Deformation Material Properties: During a tensile test using a metal that obeys the power law, the ultimate tensile strength is found to be 350 MPa. Reaching that maximum load required an elongation of 35%. Find K and n, then calculate the percent elongation when the stress is 250, 300, and 400 MPa.