# Fit a Curve by Estimating UTS

An empirical formula can be used to estimate SN/EN data from ultimate tensile strength (UTS) and Young's modulus (E).

- From the Assign Material dialog, click the My Material tab and select your created material.
- Select Estimate from UTS as the input method.
- Click to view the model description.
- Enter a value for UTS and Elastic modulus.
- Click Estimate.

## SN Properties

- $$SRI1$$
- Fatigue strength coefficient. It is the stress amplitude intercept of the SN curve at 1 cycle on a log-log scale.
- $$b1$$
- The first fatigue strength exponent. The slope of the first segment of the SN curve in log-log scale.
- $$Nc1$$
- In one-segment SN curves, this is the cycle limit of endurance (See
`Nc1`in Figure 2). In two-segment SN curves, this is the transition point (see`Nc1`in Figure 4). - $$b2$$
- The second fatigue strength exponent.

## EN Properties

- $$Sf/{{\sigma}^{\prime}}_{f}$$
- Fatigue strength coefficient.
- $$b$$
- Fatigue strength exponent.
- $$c$$
- Fatigue ductility exponent.
- $$Ef/{{\epsilon}^{\prime}}_{f}$$
- Fatigue ductility coefficient.
- $$Np/{n}^{\prime}$$
- Cyclic strain-hardening exponent.
- $$Kp/{K}^{\prime}$$
- Cyclic strength coefficient.
- $${N}_{c}$$
- Reversal limit of endurance. One cycle contains two reversals.
- $$S{E}_{e}$$
- Standard Error of Log(N) from elastic strain.
- $$S{E}_{p}$$
- Standard Error of Log(N) from plastic strain.