Dragon Skin (https://en.wikipedia.org/wiki/Dragon_Skin) claimed to withstand multiple hits without loss of performance, although there was some controversy around it.
Problem is, US Army procurement is sufficiently corrupt you can't trust testing of any physical item you hand to them, this goes back at least to the '50s when they caused the AR-10 to fail by replacing screws with wire springs....
That said, the design is obviously way too heavy without anyone even needing to weigh it.
"Once" though is one event, which might include your body armor getting hit more than once. If you're up against automatic weapons, especially the more stable heavy ones (e.g. belt fed General Purpose Machine Guns), a plate getting hit more than once in one moment is fairly likely. The military SAPI and ESAPI standards require stopping 3 hits: https://en.wikipedia.org/wiki/Small_Arms_Protective_Insert
https://www.youtube.com/watch?v=aYaSRIbPWkM&nohtml5=False