Question

3. A set of tensile test data is provided. The first column is the force measurement (kN) and the second column is the change in the gage length (Al, mm). The initial diameter and gage length of the specimen was 25 mm and 50 mm, respectively Use MatLab or Excel to do the following (a) In the same figure, plot both the engineering stress (y1) and true stress (y2) versus strain(x-axis). Insert legend at the upper left corner as "Eng. stress-strain (blue solid line)" and "True stress-strain (red dotted line)". (b) Plot log-log graph of true stress and true strain Hand calculate the following values: (c) Determine the values of strength coefficient (K) and strain hardening exponent (n) for this material. (d) What are the UTS of the material in terms of engineering and true stresses? 0.0 0.000 11.3 0.025 22.6 0.050 32.0 0.100 37.6 0.251 42.4 0.503 50.7 1.523 54.5 2.564 56.73.625 58.2 4.709 59.1 5.814 59.7 6.941 60.1 8.092 60.2 9.265 60.2 10.462 60.1 11.684 59.9 12.930 59.6 14.201 59.2 15.498 58.8 16.821

Answer 1

180 Eng. Stress- strain (blue solid line) True Stress- strain (red dotted line) 160 120 100 80 60 40 20 0.05 10.1 0.2 0.25 0.3 0.35 0.4 Eng. Strain

Answer 2