Concept

Yield stress — where it appears

The stress at which a material stops returning to its original shape. For mild steel it is an event with a plateau after it; for a rounded curve it is a definition, the 0.2 per cent proof stress, and for any material it depends on the rate at which the strain arrived.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

What is left after the first fibre yields

The elastic section modulus stops at the moment the outermost fibre reaches yield. Nothing else in the section has, so it goes on taking load — and how much more it takes turns out to be a property of the shape alone, with no dimension, no stress and no material anywhere in the answer.

sections · shape factor

The steel that is stronger in a millisecond

Every strength quoted anywhere in this collection was measured at about a ten-thousandth of a strain per second, because that is what a testing machine does, and nothing on a drawing says so. Load the same steel a million times faster and its yield stress rises by a third.

materials · strain rate

Named alongside it

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

Ductility Plastic hinge Blast Bound theorems Capacity design Collapse load Cowper symonds Dynamic increase factor Elastic modulus Equal area axis Fatigue Fracture

All concepts