2025-2026 PRACTICE PROBLEM SET SOLUTIONS #1-3 MECH 321 (Properties and Failure of Materials) Concordia University
Question 1 A specimen of ductile cast iron with a rectangular cross section of dimensions 4.8 mm ο΄ 15.9 mm (3/16 in. ο΄ 5/8 in.) is deformed in tension. Using the load-elongation data provided in the table on the right, complete problems (a) through (f). a) Plot the data as engineering stress versus engineering strain. b) Compute the modulus of elasticity. c) Determine the yield strength at a strain offset of 0.002. d) Determine the tensile strength of this alloy. e) Compute the modulus of resilience. f) What is the ductility, in percent elongation? Solution: a) This problem calls for us to make a stress-strain plot for a ductile cast iron, given its tensile load-length data, and then to determine some of its mechanical characteristics. The data are plotted below in two adjacent plots: the plot on the left shows the entire stress-strain curve, while the plot on the right extends just beyond the elastic region of deformation.