A structural member that is made out of 7075T6 Aluminum is s

A structural member that is made out of 7075-T6 Aluminum is subjected to a series of cyclic loads which produce different levels of mean and alternating stresses as 1 shown in the Table. The member is tested at room temperature. Determine whether or not fatigue failure is probable.

Solution

In the four cases mentioned, Fatigue failure is probable in case 1,2 and 4 since the number of stress cycles are less than 10⁶, but it hs a high magnitude of mean stresses.

In case 3, the mean stress is 10 ksi and alternating stress is also low i.e. 20 ksi, in this case, the fatigue failure will not happen since the specimen has crossed the infinite stress cycles.