– Consider double-edge-notched plates of 2024-T3 aluminum alloy with kt = 2.15, as in Ex. 10.4. These have a nominal stress versus life curve of the form Sar = A N B f , where Sar is given by the Walker relationship, Eq. 10.29, with fitting constants A = 1530 MPa, B = −0.217, γ = 0.733 and ( = 2.9 × 10−3. Assume that these plates will be repeatedly subjected in engineering service to the nominal stress history shown in Fig. P10.38. (a) Estimate the number of repetitions to failure. (b) If 200 repetitions are expected to be applied in service, what are the safety factors in life and in stress?