As part of the production flight test schedule all aircraft have to do a rapid depressurisation test and an emergency descent.
Emergency descent tests are not normally carried out at VMO but at the max speed with gear extended VLE.
Speed brakes will also be extended and this will give a rate of descent of at least 8000 FPM in all the aircraft I have ever flown.
You cannot dammage the structure by rate of depressurisation.
I know of a test flight where (because of a pressurisation system snag....and the crews lack of observation ) the aircraft landed at max diff (8.55 PSID). All pressure was dumped as soon as the weight on wheels switch operated and it was white out in the cabin....interesting ground roll. The designers did not need any assesment of the structure to be carried out.