In the story I'm writing a character uses a circular saw as a melee weapon and carves his opponent in half, I'm wondering if the saw would get through the pelvis or if it would deflect off? I figured that since the pelvis is rather thick the saw might not cut through it. Is this the case?
The pelvis could slice or it could shatter. Depends on the health of the victim's bones, the type of blede on the saw, and the RPMs. Also, if the motor is low horesepower, there's a possibility of the blade getting stuck, possibly burning out the motor.
It's not so much a matter of strength as it is density. A pine board made from a tree right now with 12 rings per inch will cut like butter, where a 200 year old board with 150-200 rings per inch will cut more like a tight grain oak or other hardwood. It's the density that makes a difference. After you put it on a floor it's still just as soft as the 12 ring per inch board. I hope that makes sense. As Cog said it's also going to depend on the blade you use. A wood blade will struggle (bone is dense) but a diamond blade should do pretty well. It's going to be messt either way, and if the opponent is dead and he's just cutting him up I would suggest an angle grinder with a steel or diamond blade. An angle grinder can be used like a mini demo saw and cut through anything from concrete to steel. That would probably be the fastest (but still a LOT of splatter).
Umm now I'm lost. It's nothing odd, I'm just writing a story based there and thought maybe you might know a little about the place that is un-googleable! Like local knowledge or something. Excuse my broken english. I am partially drunk.
Just adding to this. The spinning blade could even bounce off the bone and knock the wielder back a step or two. Either way, the victim will be in serious pain. Regardless of how the blade reacts to hitting bone it will cut through flesh and muscle and probably a major artery/vein. The pelvis is also a lot of bone to cut through. Maybe your character should aim a little higher and cut through an area where he will only hit the spine.
Thanks for the help everyone I'm probably going to change the scene slightly so that instead of using the saw as the primary melee weapon the character just grabs random tools and uses them to dispatch his opponent.