Explain the effect on fatigue life for the following design and environmental factors: 1) A high polish surface finish 2) A rivet hole. 3) Increasing the mean stress, but keeping the range constant. 4) A corrosive atmosphere

1) In a high polish surface finish, fatigue life will be increased.

2) In a rivet hole, there will be a decreased fatigue life.

3) By increasing the mean stress, but keeping the range constant, fatigue life is decreased.

4) In a corrosive atmosphere, a decreased fatigue life is experienced.

Explanation:

• In a high polish surface finish, fatigue failure is unlikely to be experienced because, there's a reduction of possible cracks forming on the surface. Therefore this can lead to an increase in fatigue life.

• In a rivet hole, a decreased fatigue life is likely to be experienced because of the concentration of stress in and around the rivet hole.

• By increasing the mean stress, but keeping the range constant, there ia likely to be a decrease in fatigue life beacause when the mean stress is increased without due consideration to the range, the life of the material is said to be exposed to fatigue very early.

• In a corrosive atmosphere, there is said to be an increase in resultant crack propagation of a material, thereby leading to a decreased fatigue life.