Question

S. A chassis support member made from 2024-T4 aluminum accumulates the following cyclic stress histories: Find the number of cycles n; for the stress condition 3 that the member can

accumulate after experiencing the cyclic stress history of stress conditions 1 and 2. Base all calculations on 50 percent survival rates. Note: os=70 ksi

Fig: 1

Fig: 2

Fig: 3