Solved: 2. A component made from A27 cast steel was inspected and found to hav

Question

2. A component made from A27 cast steel was inspected and found to have a quarter-circular corner crack with a radius of 0.1 in. The fracture toughness for this steel at the operating temperature (75°F) is about 220 ksiin. Using the da/dN versus AK curve shown below for zero- to-maximum loading (R = 0), with Paris parameters given, determine the number of cycles to fast fracture if the applied stress range is AS, = 50 ksi (zero-to-maximum tension loading, R = 0). Assume that the crack size is negligibly small compared to the thickness throughout the life of the component to enable analytical integration of the crack growth relationship. You can use these K solutions from the Dowling textbook (2nd Ed.): Call P P de 1 - 0637 6728 6M F 6712 + 124 78 Now: "Diff onion or bending, respectively. Figure 6.17 Stress interality factors for alan embedded circular crack under un quarter-dicular comer crack, and id half-circular surface crack in a shatt, where the latter If the operating temperature is instead O'F, then the fracture toughness is reduced to 120 ksi in Determine the number of cycles to failure in this case. Assume that the crack growth rate is not affected by temperature. Comment on the impact of this lower temperature on the fatigue life. 10 Crock Growth Rate, inches/cycle 10 ON G+1.6710 Test Tema 75°F Specimen Type 1. CTS 10 10 20 30 40 50 70 90 150 200 60 80 100 Stress intensity Renge, ak, ki F3.15