Originally Posted by
Robinhood4x4
Are you saying you're going to cut off the factory crush zone in the frame rails? If not, then you don't need a new crush zone since it'll still be there. If you are then...
The problem is we don't know when the factory crush zone is supposed to activate in an accident so it would be a crap shoot to design our own crush zone and think it would activate at the same impact force as the factory crush zone. Ideally, you would have to reverse engineer the toyota design by modeling it in Finite Element Analysis and then do some actual testing to verify the model. I work with Stress Analysts and I do the actual testing and even I would have a hard time designing such a thing.
I assume you're going to design it for a winch? You would have to do the stress calculations to make sure that your new crush zone is strong enough to withstand a worst case scenario of a sideways winch pull, but weak enough to crush in an accident.
What I'm trying to say is that designing a crush zone is not a trivial thing and I think you should just build the bumper and not worry about it. It'll be fine.