Structural Engineering & Statics
where the load goes
Concept

Slenderness

4 essays name this object, across 2 fields. What follows is each of them, and the objects they name alongside it.
worst secondary bending: 24.3% of the axial stress, in the member markedaxial force there 16.7 kN · end moment 0.20 kNm · slenderness of the member 18the same members, the same loads, the same solver — only the releases differ

The joint that is not a pin

Every truss on this site is analysed as though its joints were frictionless pins. Almost none are. The bending that follows is called secondary, which is a claim about size — and the claim is checkable.

structures · truss 5010015020000.20.40.60.811.2slenderness (effective length ÷ radius of gyration)they cross at λ = 75squashingEuler bucklingreal columns, which are neither

Strong enough and still falls over

A column can fail at a fraction of the load its material could carry, by going sideways. Buckling is a failure of stability rather than of strength, and it is decided by geometry.

stability · buckling K = 0.5both ends fixedK = 0.7one fixed, one pinnedK = 1both ends pinnedK = 2fixed at the base, free at the topsame column, same section, four ways of holding the endsthe load at which each buckles goes as 1 ÷ K² — a factor of sixteen across this row

The ends decide the length that matters

Four columns of identical height and section, buckling at loads sixteen times apart. Nothing differs but what is holding the two ends.

stability · effective length 1002003004005006007000200400600plate width (mm)slender beyond 370 mmyieldcritical stress — inverse square in the widthwhat the plate actually delivers, over its full width

The plate that ripples, and the width that is left

A wide thin plate in compression buckles at a stress that has nothing to do with the strength of the material. It then goes on carrying load — the middle drops out, and the edges work harder.

stability · plate buckling

Named alongside it

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

Effective lengthBracingBuckled mode shapeCritical loadEffective widthEnd restraintEuler bucklingIdealisationImperfectionJoint rigidityMethod of jointsMoment connection

All concepts