Every material stretches elastically according to Hooke's law until it reaches its yield strength, after which it deforms plastically or fractures. Temperature changes also cause materials to expand or contract via thermal strain.
ε = σ / E (elastic strain, Hooke's law)
ΔL = α · L0 · ΔT (thermal expansion)
Failure when σ > σ_yield
- Material — switches Young's modulus E, yield strength, thermal expansion coefficient α, and visual texture between steel, concrete, timber, and brick.
- Applied stress — compressive load on the sample block; the block visibly compresses more as stress rises, and cracks/necks near failure.
- Temperature — heats or cools the block, causing thermal expansion or contraction shown as a subtle size change and color shift.
Engineers select materials by comparing these exact properties — a steel beam and a concrete column of the same size behave very differently under identical loads, which is why material choice drives structural design.