Method of Virtual Mean Stress Fatigue Curve Equation
Strength and Mechanics of Materials
The virtual mean stress has a corresponding mean strain which conditions result in biased stress/strain limits under cyclic load. It is shown that residual stress relaxation is associated with mean stress shift in stress-axis direction and mean strain shift in the strain axis direction.
Method of Virtual Mean Stress
Where: | |
= Amplitude of normal (shear) stress [MPa,psi] | |
= Endurance limit at constant strength [MPa,psi] | |
= Mean cycle stress [MPa,psi]] | |
= Virtual mean stress [MPa,psi] | |
= Haigh factor diagram narrowing | |
= Coefficient; For Bending
For shear |