Yield strength is the column of a property table that capacity calculations reach for, and it comes with a reading rule: for structural metals the published figures are specified minimums — what a mill must certify — not typical values, and real material usually tests higher. The spread across common metals is wide: ASTM A36 steel at 250 MPa minimum, A992 W-shapes at 345, annealed 304 and 316 stainless at 205, aluminum 6061-T6 at 276, and copper C11000 anywhere from 70 to 340 MPa depending on temper. Some materials simply have no defined yield — concrete capacity runs on f′c instead, and wood tables carry no yield column at all.
Design turns fy directly into member capacity. A steel-member check pulls the grade yield from its database and computes the moment capacity from the plastic modulus — Mc = fy·Zx/γM0 under Eurocode 3, φMn = 0.9·fy·Zx under AISC 360 — and shear from the web area at fy/√3. A W14x30 (Zx = 782×10³ mm³) in S275 steel gives Mc = 275 × 782×10³ / 10⁶ = 215.1 kN·m before any lateral-torsional buckling reduction, and a shear capacity of 385.6 kN.
The number is only as good as its provenance: anything safety-critical gets re-checked against the governing standard or the supplier certificate for the actual grade purchased, and where tables print ranges — concrete, wood, plastics — the range reflects genuine variation with grade, moisture, and formulation rather than measurement noise.