There are 3D applications. They're probably your best bet for doing something like this. You'd drive yourself nuts trying to do it in AE.
it all depends on how elaborate is this effect supposed to be.
here's 2 tutorials making a face of polygons or triangles with after effects and a 3D plugin called "Plexus". you should investigate if it offers the flexibility you need:
of course there is also the good ol' "Shatter" effects that allows some 3D convincing shatter in all sorts if ways:
and you can move the Ae camere to create interesting movement and it's all in fake 3d that is quite convincing
I was going to suggest Shatter as a place to start. Set shape to triangles1, repetitions to 300, gravity to zero, force to 2 and then pre-compose and time remap, then select all keyframes and use the keyframe assistant to time reverse the keyframes.
You can animate Force 1 to set the timing of the shatter to anywhere you want. Better yet, use a gradient for a shatter map and make the pieces fly off in the order you want them to.
To learn more about Shatter type "shatter" in the search help field at the top right corner of AE and check out the help files and tutorials that are available. Don't rely on YouTube to give you much useful info on this effect originally designed by my friend Brian Maffit....