"Each rendition of the Corvette chassis has been stiffer than the one before it. This is the primary goal of the hydroformed frame rails." -maXJohnson
The reason GM is putting so much work into making the Corvette frame stiffer is because they are trying to get the vette to be as stiff as all the uni-body competition. Because it is a fiberglass body a steel frame is necessary. This gives really low center of gravity (light fiberglass body, heavy steel frame)
maXJohnson:
You seem to be into the technical stuff, try doing a torsional stiffness calculation on 4 inch high x 48 inch wide ladder frame and compare it to a 48 in x 48 in sheet metal tube (uni-body). To make it easy just estimate the frame as a 4x48x120 tube and do a cantilever deflection calculation. Now using the same load you chose for the frame, do the same calculation with a 48x48x120 tube (approximation of a cherokee body). See which one deflects more and then find the wall thicknesses needed to make them have equal deflections.
by the way...
I cut the top of my 88 Cherokee and drove it around for quite a while. The doors all opened and closed just fine and I never noticed any flexing of what was left of the body. I eventually put a roll cage in for safety.
forums, you should find the unibody example to be the stiffer design (by a factor of at least 2).
