Concept

Toughness — where it appears

A material's resistance to a crack running, measured as the stress intensity at which one propagates rather than as a stress. It falls with temperature and with loading rate, so a steel that is ductile under a slow load at its service temperature can be brittle under a fast one.

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

Squeezed sideways into a different material

Concrete in a cylinder test fails by splitting apart sideways under a load pushing it down. Put a hoop round it and the splitting has to stretch steel — and a lateral pressure of a twelfth of the strength raises the strength by half and the ultimate strain by eight.

materials · confinement

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 Arching Blast Capacity design Collapse load Confinement Cowper symonds Dynamic increase factor Elastic modulus Energy dissipation Fatigue

All concepts