Originally Posted by
FLEXPWR
The reason there is a MMO limit, say 0.82, is that beyond it, you will find some local areas on the wing that will reach or exceed Mach 1.
Sorry, Mmo is not determined by the speed at which the local flow is transonic. That would be Mcrit, the speed at which the transonic drag rise starts (if we ignore low speed high lift effects). Mcrit is usually BELOW Mmo.
Mmo is set either by considerations of airframe loading (where it's called VC in the regulations, but there's a link between VC and Vmo, and thus indirectly to Mmo) or by considerations of aircraft handling (various criteria must be met at Mmo) or by considerations of various "upset" cases, which start at Vmo/Mmo and must not exceed VD/MD (or VDF/MDF as appropriate).
But your comments about shocks inducing loads on components that they were not designed to take is valid.