Materials, Properties and Design

· The diagram opposite shows force-displacement data obtained on an aluminum sample. In order to convert this into an engineering stress-strain curve the force must be normalized with the initial cross-sectional area and the deformation normalized by the initial length.
· Engineering Stress = σ_N =
(Force/ Initial Area) = (F / A₀)
· Engineering Strain = ε_N =
(Change in Length / Initial Length) = (ΔL / L₀)