Radius of gyration — where it appears
Named by 3 essays across 2 fields — each of them below, with the objects they name alongside it.
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.
The one length a section takes into a column
A section has an area, a second moment, two section moduli, a shear centre and a torsion constant. A column has heard of exactly one of them, and it is none of those — it is the length √(I/A), which is where the whole area would have to sit to give the section the stiffness it has.
The column made of two columns
A solid column buckles when its bending stiffness runs out. A laced one has a second way to go — the lattice shears, the chords stay straight — and the two flexibilities add rather than the two stiffnesses. A battened column reaches 23% of its own Euler load and behaves as though its slenderness were twice what it is.
Named alongside it
The objects these essays reach for when they reach for this one.
BucklingBuilt up columnEffective lengthEuler loadSlendernessAsymmetric sectionBattenBuilt up sectionChordCritical loadEffective slendernessEngesser