Hi, Jon!
Wow, I'm no Titanic forensics expert, but I'll attempt an extremely short summary.
Cameron's film shows the Titanic poised at a 45-degree angle, with the cracking starting on the uppermost deck, moving downward. There's a lot of debate whether the ship ever actually reached a 45-degree angle before breaking up.
The feeling of a number of experts is that, since a ship is essentially a hollow tube, like the center of a roll of paper towels, the increasing weight on the bow, coupled with the stern's determination to retain its horizontal stability, put heavy stress on the keel and double bottom, causing them to compress on themselves, thereby tearing the ship apart from bottom to top. The wreck is in two major sections, but a good portion of the ship between those two sections isn't attached to either one of them. In addition, the back end of the bow section is collapsed downward, which could have been caused by downblast, by impact with the seabed, or by being pulled downward towards the keel by the separation - or by all three.
Jon, you might want to check these out:
http://titanic.marconigraph.com/tech3.html
(Question 38)
https://www.encyclopedia-titanica.org/item/1507/
Now, the forensic experts can join in and pick me to pieces. (But please, gentlemen, be kind!)
Roy