Flexural rigidity — where it appears
Named by 4 essays across 3 fields — each of them below, with the objects they name alongside it.
Neither pinned nor rigid, which is every real connection
Frame analysis offers two options for a joint and reality supplies a continuum between them. Worse, the boundaries are not properties of the connection at all — the same end plate is rigid on a short stiff beam and semi-rigid on a long slender one.
The area of a diagram is a rotation
A deflection is the double integral of a bending moment, and the two constants of integration are the whole difficulty. Mohr's theorems replace them with two pictures — an area, and where that area's centre of gravity sits.
Built to the wrong shape on purpose
A cambered beam is fabricated curved upward so that load bends it down to something like straight. Nothing in the analysis changes, no stress anywhere is altered, and almost every mistake made with it is a bookkeeping mistake about which loads count.
Guessing the shape, and getting the load anyway
A column's buckling load can be had from a shape that is wrong everywhere, because the energy criterion is stationary at the true mode. The error in the load is the square of the error in the shape, and it is always high.
Named alongside it
The objects these essays reach for when they reach for this one.
DeflectionStiffnessSuperpositionBuckled mode shapeCentroidClassificationComposite actionConnectionConservation of energyConstruction sequenceCreepCritical load