Concept

Blast — where it appears

A pressure that rises almost instantaneously and decays over a few milliseconds, delivering an impulse rather than a sustained force. Because it is over before the structure has moved, the response depends on the momentum delivered, the mass, and how far the structure can travel while yielding.

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

Also named here as strain rate — the same set of essays touches all of them, so they are one junction rather than several.

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

The load that is over before it has moved

A blast delivers an enormous pressure for a few milliseconds. Everything else in this field asks what force a structure can carry; a load that has come and gone before the structure has travelled any distance is not asking that question, and the answer turns out to depend on the mass and the ductility with the strength barely in it.

dynamics · blast

Named alongside it

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

Plastic hinge Strain rate Bound theorems Capacity design Collapse load Cowper symonds Damping Ductility Ductility demand Dynamic amplification Dynamic increase factor Elastic modulus

All concepts