Structural Engineering & Statics
where the load goes
Concept

Stress strain — where it appears

3 essays name this object, across one field. What follows is each of them, and the objects they name alongside it.
00.5%1%2%2%0100200300400500600strainstress, N/mm²the 0.2% proof stress: 460 N/mm²mild steelhigh-strength steelaluminium

The stress at which nothing in particular happens

One material in six has a yield point that a specimen actually does something at. For all the others the yield stress is a construction — a line drawn at an arbitrary offset — and every calculation on this site depends on it.

materials · proof stress 00.1%0.2%0.3%0.4%0.5%0.6%050100150200250300350strainstress, N/mm²mild steelaluminiumconcretetimber

The one number a stronger steel does not change

Geometry beats material almost everywhere on this site. Stiffness is the exception in the other direction — it cannot be bought at all, because every steel ever made has the same elastic modulus.

materials · elastic modulus 00.5%1%2%2%050100150200250300350strainstress, N/mm²mild steelcast iron

The property that appears in none of the equations

Ductility is in no design formula on this site. Every method on this site depends on it — and a brittle structure does not merely fail early, it makes the analysis wrong.

materials · ductility

Named alongside it

The objects these essays reach for when they reach for this one.

DuctilityElastic modulusProof stressBrittle fractureBucklingConstitutive lawIdealisationLoad pathLower bound theoremMaterial selectionMoment redistributionPlastic hinge

All concepts