Hands-on exercise – Visualizing Materials Properties

Put the lesson Visualizing Materials Properties into practice by writing a program yourself.

Plot and report a tensile test

The problem

The starter code holds the full stress–strain curve of a steel sample.

Find the ultimate tensile strength (the highest stress) and the strain at which it occurs, then plot the curve with that point highlighted.

Your program should

Use np.argmax() to find the position of the highest stress.
Print UTS: 520 MPa and At strain: 0.120 (3 decimal places).
Plot the curve with strain in % on the x-axis, label both axes with units, mark the UTS with a single highlighted point, and add a legend.
The automatic check compares your printed output; check the plot by eye.

Expected output

UTS: 520 MPa
At strain: 0.120

Your solution

Write your program below and press Run. Each run is checked against the expected output.

main.py

Loading editor…

or press Ctrl + Enter in the editor

Output

Press Run to see what your program prints.

Need help?

One possible solution. Other programs that print the same output are correct too.

solution.py

import numpy as npimport matplotlib.pyplot as pltstrain = np.array([0.0, 0.001, 0.002, 0.005, 0.02, 0.05, 0.08, 0.12, 0.16, 0.20, 0.22])stress = np.array([0, 200, 350, 380, 400, 450, 500, 520, 510, 470, 430])   # MPapeak = np.argmax(stress)print(f"UTS: {stress[peak]} MPa")print(f"At strain: {strain[peak]:.3f}")plt.plot(strain * 100, stress, marker="o", markersize=4, label="Steel")plt.plot(strain[peak] * 100, stress[peak], "o", markersize=9, label="UTS")plt.xlabel("Strain (%)")plt.ylabel("Stress (MPa)")plt.title("Tensile test")plt.legend()plt.grid(True)plt.show()

Output

UTS: 520 MPa At strain: 0.120