Hi Ben,
Thanks a lot for the file and using dropbox.
To have a good dynamic simulation, the details need to be included. To leave the (Dynamic Tag> Shape) to Automatic will not do that. Moving Mesh is the setting you need here.
The Shape parameter (Dynamic Tag) of the “chunks”, while detailed, will create an overlap of any simplified shape. This causes the explosion. Only the Moving Mesh will take everything into account. With the detailing, this requires a lot of calculations. It needs to be cached to have any fun with the scene. In other words, it will be quite slow otherwise.
Since it needs to be cached, you could also uncheck the detailing for a moment, cache it, and then switch the detailing back on. It will not be 100% perfect, and some details show up more prominent.
An example is here:
https://www.amazon.com/clouddrive/share/goa2oj7z2KvbMpm5xFLRgECzmupRCQUUhN3uWuQ89AK
Please note that I have animated the Size increase. First, a tiny little bit into the negative, to keep the volume “as one”, then on the impact a little bit larger, to get the details into account.
I used here the MoGraph Cache, as it can be saved.
All the best