# MaterialFracture:Problems:Level 2

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 Introduction Background Basic Layout Examples Problems Run Simulation Assessment Credits Etomica Modules

These problems are suitable for undergraduate students in material science course.

Simulation
With the structure of the triangular lattice, run the simulation at room temperature. Now, observe and record five properties from the table in the module (gage length, load, elongation, stress and strain) at a spring constant, which is small and can make the system go back to the original state when the external stress is removed. Increase the spring constant little by little and remove the external stress. Observe whether the present state goes back to the previous state. Repeat this process until the structure fractures.

1. Calculate every property produced from the tensile test: Tensile Strength, Yield Strength, Ductility, Modulus of Elasticity, and Toughness. For the calculation of Toughness, the fitting procedure might be involved and second order polynomial is fine but no less.
2. Construct a simulation, as above example, which the structure represents High Strength and Low Ductility and solve problem 1.
3. Construct a simulation, as above example, which the structure represents Low Strength and High Ductility and solve problem 1.
4. Compare the results from problem 1, 2 and 3. Which pattern does the stress-strain graph follow, engineering or true one? Can you catch a transition point between the elastic deformation and the plastic deformation? What are the differences of the results from comparison?