Tangent modulus — where it appears
Named by 3 essays across 3 fields — each of them below, with the objects they name alongside it.
The stress that was there before the load
A rolled steel section leaves the mill carrying eighty N/mm² of stress with nothing applied to it, in a pattern that sums to no force and no moment. It is invisible to every calculation and it is the knee in every column curve.
The column that had yielded before it was loaded
A real column sits below both of the two straight answers over the whole middle of the slenderness range, and the usual explanation — that it was not straight — is only half of it. The other half is that the flange tips had already yielded when it left the rolling mill.
Held by something that goes soft
A guy is a cable, so it has no stiffness of its own — what resists a mast's movement is the guy's geometry changing, and how much of that there is depends on the tension already in it. Wind pushes the mast towards the leeward guy, which is the one losing tension.
Named alongside it
The objects these essays reach for when they reach for this one.
BucklingColumn curveImperfectionResidual stressSelf equilibratingAnchorBeam columnCableCritical loadElastic limitElastic supportFirst yield