• You must first define a static or transient structural analysis before defining fatigue behavior or results.

• The model must contain only solid geometry for fatigue evaluation. Beams, shells, and shell pair idealizations are not supported. References must be bodies or components.

• Ensure all required fatigue material properties are defined before defining fatigue results.

• An advanced Creo Ansys Simulation license is required to define fatigue behaviors, fatigue results and to run a fatigue analysis.

• Stress Life Curve—The Stress Life (S-N) curve defines the relationship between alternating stress amplitude and the number of cycles to failure under elastic (high‑cycle) fatigue conditions. It helps predict the fatigue life of materials under cyclic loading conditions. Define the stress life curve as a table function of stress amplitude versus cycles to failure. Stress amplitude values must be positive. Stress amplitude and number of cycles must both use the same scale —either linear or logarithmic. (Linear for stress amplitude and logarithmic for number of cycles, and vice versa is not supported).

• Strength Coefficient—The strength coefficient is the fatigue strength intercept in the strain‑life (ε–N) equation. It represents the stress amplitude at one reversal (2N = 1) extrapolated from the elastic portion of the fatigue curve. A material with a higher value of strength coefficient resists fatigue damage better in the elastic regime.

• Strength Exponent—The strength exponent defines the slope of the elastic portion of the strain‑life curve on a log‑log scale. A more negative value of strength represent a steeper slope which indicates a faster reduction in fatigue life with stress.

• Ductility Coefficient—The ductility coefficient represents the fatigue ductility intercept, corresponding to the plastic strain amplitude at one reversal. It is used in strain‑life fatigue analyses and represents the plastic strain contribution to fatigue life. A higher value of ductility coefficient means a material can tolerate more plastic deformation before failure.

• Ductility Exponent—The ductility exponent defines the slope of the plastic portion of the strain‑life curve. It is used only for strain‑life fatigue and controls how quickly fatigue life decreases with increasing plastic strain. The value of ductility exponent is typically negative. More negative value of ductility exponent implies that the material loses fatigue life rapidly under plastic deformation.

• Cyclic Strength Coefficient—The cyclic strength coefficient defines the stress required to cause a unit plastic strain under stabilized cyclic loading. It is used for cyclic stress–strain behavior and is required to convert elastic stresses into cyclic plastic strains. It is important for strain‑life fatigue and mean stress corrections. A higher value of cyclic strength coefficient implies a higher resistance to cyclic plastic deformation.

• Cyclic Strain Hardening Exponent—The cyclic strain hardening exponent defines the nonlinearity of the cyclic stress–strain curve. When used with the cyclic strength coefficient it governs how stress increases with plastic strain under cyclic loading. It influences strain amplitude and is used in fatigue life calculations. A higher value of cyclic strain hardening exponent implies a stronger cyclic strain hardening while a lower value indicates that the material softens more easily under cyclic loading.

◦ Stress life—Stress life is typically used for high-cycle fatigue and calculates fatigue using stress results and stress-life curves.

◦ Strain life—Strain life is typically used for low-cycle fatigue and uses strain-based equations. For this method, you have to define the infinite life limit and other strain life parameters.

◦ Fully reversed—This is a constant amplitude loading with a zero mean value. The maximum stresses (or strains) alternate symmetrically between equal tension and compression.

◦ Zero—In this type of constant amplitude loading, stresses vary between zero and a positive value. It has a non-zero mean stress value.

◦ Ratio—In this type of constant amplitude loading, the stresses vary between two values defined by the loading ratio.

◦ Mean stress theory—Select from values of None, Goodman, or Gerber for stress life type of behavior. See the topic Choosing the Right Mean‑Stress Correction in Fatigue Design as a reference when selecting the mean stress theory to be used in fatigue behavior.

◦ Loading ratio—Specify the loading ratio. A loading ratio of 3 means stresses or strains vary between the actual amplitude and 3 times the amplitude with a mean of twice the amplitude.

◦ Infinite life—This is the maximum life of the strain life analysis type.

◦ Design life—Specify the life that the model is being designed for.

◦ Life units—Select the units of life. This can have values of blocks, days, minutes, seconds etc.

• Biaxial Indication

• Equivalent Alternating Stress. Use stress-life fatigue behaviors for Equivalent Alternating Stress results.

• Fatigue Damage

• Fatigue Life

• Safety Factor