Question

Wide sheets of steel are to be used for studying fatigue crack propagation. A hole with a diameter of 0.04 inch is drilled in the center of the plates so serve as a "crack starter". Assume the hole surface is smooth. The plate is to be subjected to zero-to-maximum cycle loading (R = 0). The material properties of the pate are

E = 30*10^3 ksi

S = 115 ksi

C = 3.6*10^-10

m = 3.0

K = 100 ksi sqrt in

a) Determine to nominal maximum stress required so that a crack can be presented at 10^6 cycles

b) Determine the number of cycles needed at the nominal maximum stress to grow a crack from a length of 0.01 inch to final fracture

c) Estimate the total fatigue life at the nominal maximum stree

Answer 1

-rt hole with a diametル2004 inch a-n a Nominal mazimum Stiex 2-0 a-0 The number ot ryck maumum stres to groVal o o ol inch to hn e nominal | dina enum we know that 2789 10 11 12 13 314 15 16 17 18 19 20 421 22 23 24 25 26 27 5 28 29 30 31