To calculate the modulus of elasticity for a material and the yield stress based on the stress-strain
Question:
To calculate the modulus of elasticity for a material and the yield stress based on the stress-strain diagram.
Some materials do not have a well-defined yield point (Figure 1) . Instead, the stress-strain diagram gradually curves away from a linear response after a certain point. One method of defining the yield stress for such a material is the 0.2% offset method. The slope of the linear region is calculated. Then a parallel line is drawn starting at a strain of 0.002. The intersection of this line with the stress-strain curve defines the yield stress.
The following data were obtained using a tension testing machine with a sample at 20?C that had a circular cross section with diameter d0 = 12.5 mm and a gage length of L0 = 50 mm .
Load [kN] | Elongation [mm] |
0.0 | 0.0 |
5.0 | 0.1 |
10.1 | 0.2 |
15.1 | 0.3 |
20.1 | 0.4 |
25.2 | 0.5 |
30.2 | 0.6 |
33.5 | 0.7 |
36.3 | 0.8 |
38.7 | 0.9 |
40.8 | 1.0 |
42.7 | 1.1 |
44.4 | 1.2 |
45.9 | 1.3 |
47.2 | 1.4 |
48.1 | 1.5 |
Materials Science and Engineering An Introduction
ISBN: 978-0470419977
8th edition
Authors: William D. Callister Jr., David G. Rethwisch