Structural Engineering & Statics
where the load goes
Concept

Truss — where it appears

An assembly of straight members meeting at joints that carry no moment, in which every member is a two-force member with one number in it.

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

200 kN200 kNthe chord — and the line of action1.20 mbending moment = P × offsetpeak 240 kNmbending stress is 24.0 times the axial stress at the worst section

The member with only one direction

If a body is in equilibrium under forces applied at exactly two points, those forces are equal, opposite and along the line joining the points. It is three conclusions from two equations, it is the shortest real theorem in statics, and nearly everything on this site depends on it without saying so.

equilibrium · two force member 10^-610^-410^-210^-1610^-1410^-1210^-1010^-8size of the dummy loadrelative errorround-offand nothing elsebest 2e-16∂U/∂P = 1.720635e-2 · unit load = 1.720635e-2

The deflection that is a derivative

A structure's strain energy is one number. Differentiate it with respect to a load and out comes the displacement under that load — and the trick that makes it a method rather than an identity is that the load does not have to be there.

deflection · strain energy

Named alongside it

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

CastiglianoComplementary energyDeflectionDummy loadEccentricityEquilibriumFlexibilityFree bodyFunicularImperfectionLine of actionLinearity

All concepts