MySQL Crashed every hours
Having a query cache of 45GB is definitely not a good idea. It should not be more than say 128MB, usually much lower numbers are suggested, or even totally disabling it. Query cache of this size makes everything slow because on any update to any table it has to be traversed and entries invalidated, and you can have many entries to invalidate in 45GB.

The crash itself looks like a bug in the server for handling the big cache (signal 11 is a segfault afaik). You can check if it is known and if not then submit a bug report.

But definitely set the cache size well under 1GB, it is better to give that memory to innodb buffer pool.