ROOF CRUSH 7 .
TESTING & EVALUATING:
The illustrations on the right show various test types and protocols for roof strength testing. Another important one not illustrated is the "cork screw" test where one side of the vehicle drives up a steep ramp while the other side is on level ground. All the various tests have their strengths and limitation and all will produce variable outcomes if you look closely enough at the results. The "dynamic" tests, with the vehicle moving, are generally seen to be more representative of actual highway accidents than the static roof loading tests, but they present difficulties with respect to "repeatability".
The "Problem" with testing as seen by many testers:
(FROM: SAE 2001-01-0476 )
In other words, for dynamic tests, we at least want to have similar initial conditions through a series of tests, without a hit and miss approach, which requires a larger number of tests and more money. But while this may be a problem for academic or private testers, is it necessarily a problem for vehicle manufacturers? Many have claimed it is over the years, so the question is of importance.
But vehicle makers typically do hundreds of calibration (airbags) and certification tests for each new platform, so why can't they do hundreds of rollover tests to cover all the variables? They could, of course, but they don't because for most vehicles the results of each test will be the same, failure with significant loads or ground contact.
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Static 571.216 test.
Dolly test.
(From: SAE paper #: 2003-01-0172)
