well, i'm not sure if this'd fall under the typical realm of puppetry or not, but i thought this might be as good a place as any to ask for some help. i'm currently working on making costumes of all the characters from the popular horror game "five nights at Freddy's". if you haven't heard of it, it's a game about a haunted chuck-e-cheese style restaurant, and the possessed animatronic robots therein. one character in particular is posing to a real challenge though: the mangle. basically, she's an animatronic that's been torn apart and left with a nearly bare skeleton. for the costume, i'm attempting to create an articulated skeleton rig which will more or less wrap around someone's body, like she's circling/grabbing them like a snake and peering over their shoulder. the main problems i'm running into here are with the joints and weights. the head is constructed from EVA foam, and so it's rather hefty, causing it to weight and pull the rig and hinges apart. as it is now, i've just attached simple brass hinges to PVC pipes for the limbs, but even after just 10 minutes of wearing/suspending the head, the hinges are twisted and in some cases broken outright. i'm wondering if anyone here might have some advice for how to build better joints, or on ways to balance out top heavy puppets maybe?  
on a side question, i've seen some puppets built with a foam that looks similar to what nerf toys (darts, sportsballs, etc) are made of, but i've got no idea what it's called? if anyone knows it'd be appreciated, thanks!
edit: adding some references/what i've done so far:

3D model i'm basing my design off of

Brass is too soft of a metal. Hard to really give any real advice on the info you gave but general alternatives for hinging would be one a harder alloy metal hing or leather straps. You might even be able to get away with heavy cord or rope for some of the hinges.

When you talked about the skeleton curling around someone it reminded me of Tioh's animatronic tail in this page below. Maybe his mechanism will give you some ideas you can try to make the curling movement.

http://puppetsandstuff.com/community/index.php/topic,8462.135.html

My nephew was terrified of Chucky Cheese robots, guess he was not the only one.