See that ductile metals deform plastically over a wide strain range before fracturing, while brittle materials fracture almost immediately after their elastic limit with no warning plateau.
Elastic region: σ = E·ε (Hooke's law)Ductile metals: elastic → yield → plastic hardening → necking → fractureBrittle materials: elastic → fracture (no plastic region)With Steel selected, increase strain past 0.25 and watch it move through yielding, necking, and finally fracture, with stress dropping back to zero.
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