σ = K(ε₀ + ε)ⁿ · (1 + (ε̇/C)1/p)
where: σ — true stress, K — strength coefficient,
ε₀ — initial strain, ε — plastic strain, n — hardening exponent,
D = (1 + (ε̇/C)1/p) — Cowper-Symonds factor, ε̇ — strain rate
| Parameter | Symbol | Value | Unit |
|---|
| True UTS | σu,true | — | MPa |
| Hardening Exponent | n | — | — |
| Strength Coefficient | K | — | MPa |
| Residual Plastic Strain | ε₀ | — | — |
| Tangent Modulus | Etan | — | MPa |
| C Parameter | C | — | s⁻¹ |
| p Parameter | p | — | — |
| Young's Modulus | E | — | MPa |
| Yield Strength | σy | — | MPa |
| UTS (Engineering) | σu | — | MPa |
| Elongation | A | — | — |
| Density | ρ | — | t/mm³ |
| Poisson's Ratio | ν | — | — |
| Failure Strain | εf | — | — |
| Total Strain, εtotal [—] |
Plastic Strain, εplastic [—] |
True Stress, σ [MPa] |
References
1. Swift, H.W. (1952). Plastic instability under plane stress. J. Mech. Phys. Solids, 1(1), 1–18.
2. Cowper, G.R. & Symonds, P.S. (1957). Strain-hardening and strain-rate effects in the impact loading of cantilever beams. Brown University Report.
3. VarmintAl. Material Collection for Finite Element Analysis.
www.VarmintAl.com/aengr.htm