PSI - Issue 17

Pranav S. Patwardhan et al. / Procedia Structural Integrity 17 (2019) 750–757 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

6

755

0 100 200 300 400 500 600 700 800

100 150 200 250 300 350 400 450 500

(k)

(l)

 p-L = 0.00934

Inconel 600 Atlas of Stress Strain curves

SAE 950X Krauss (1980)

 p-L = 0.0099

Experimental Ramberg-Osgood fit Estimated

Experimental Ramberg-Osgood fit Estimated

True stress,MPa

True stress, MPa

0 50

0

0.1

0.2

0.3

0

0.05

0.1

0.15

0.2

True strain

True strain

0 100 200 300 400 500 600 700

600

(m)

(n)

500

 p-L = 0.0094

400

 p-L = 0.0166

300

SAE 980X Krauss (1980)

A663 Bethlehem (1985) Experimental Ramberg-Osgood fit Estimated

200

Experimental Ramberg-Osgood fit Estimated

True stress,MPa

100 True stress, MPa

0

0

0.05

0.1

0.15

0

0.05

0.1

0.15

0.2

True strain

True strain

100 150 200 250 300 350 400 450

0 100 200 300 400 500 600

(p)

(o)

 p-L = 0.00213

 p-L = 0.0111

A36 U.S. Steel (1971) Experimental Ramberg-Osgood fit Estimated

A242 Dolega (1953)

Experimental Ramberg-Osgood fit Estimated

True stress,MPa

True stress,MPa

0 50

0

0.005 0.01 0.015 0.02 0.025

0

0.05

0.1

0.15

True strain

True strain

Fig. 4 a-p. Comparison of true stress-strain curves from experimental data, fitted by the Ramberg- Osgood relationship and estimated using Luder’s plastic strain at plateau,  p-L . As it is seen from Fig. 4 a-p, that by using true plastic yield strain at end of yield s tress plateau (plastic Luder’s strain) gives fairly good estimation of stress-strain curves, and thus strain hardening exponent N. Figure 5 compares the Ramberg-Osgood constants N=1/n and H calculated from experimental curve and estimated by the proposed method.