Concept

Interaction diagram — where it appears

A locus of the combinations of two or more actions a section can carry at once, drawn in the plane of those actions. It replaces a pair of independent checks with one boundary, and its shape says whether the two actions simply add or whether the section carries more of the combination.

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

Two moments and a neutral axis that obeys neither

Tilt the load on a rolled beam by five degrees and the neutral axis swings by seventy. The section is doubly symmetric, its product of inertia is exactly zero, and none of that helps — because what decides the axis is the moment ratio multiplied by a stiffness ratio of thirty.

sections · biaxial bending

The shear strength nobody measured

Every web on this site is checked against the yield stress divided by the square root of three, and no test produced that number. It is a consequence of a decision about what makes a metal yield, and the alternative decision gives a different answer by fifteen per cent.

materials · yield criterion

Named alongside it

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

Bending stress Biaxial bending Confinement Deviatoric stress Ductility Equivalent stress Hydrostatic stress Mohr circle Neutral axis Plastic modulus Plasticity Principal axes

All concepts