Designations Independent Dependent

Equation of Curves

R²

σ

Variable, y

Variable, x

70TFA

Stress

Strain

y = −1.411x² + 0.487x − 0.013

0.973

0.25

60TFA

Stress

Strain

y = −1.572x² + 0.527x − 0.014

0.984

0.25

50TFA

Stress

Strain

y = −1.423x² + 0.499x − 0.012

0.979

0.19

10C

Stress

Strain

y = −0.842x² + 0.402x − 0.010

0.984

0.12

15C

Stress

Strain

y = −0.946x² + 0.443x − 0.010

0.968

0.31

20C

Stress

Strain

y = −0.351x² + 0.263x − 0.003

0.967

0.37