Dynamic amplification — where it appears
Also named here as impact factor, impulse — the same set of essays touches all of them, so they are one junction rather than several.
Twice the deflection, for the same load
A weight placed gently on a beam deflects it by one amount. The same weight let go from rest, a millimetre above the same beam, deflects it by twice as much — and the factor of two is exact, for every structure ever built.
The weight that was dropped
A half-tonne load lowered onto a beam produces 5 kN. The same load dropped one metre onto the same beam produces 160 kN — and onto a beam ten times softer, 54 kN. The stiff structure is the one that suffers, which is the opposite of every other rule on this site.
Named alongside it
The objects these essays reach for when they reach for this one.
Conservation of energyImpact factorImpulseStrain energyCrane loadingFall arrestFree bodyNatural periodShock spectrumStiffness