Originally Posted by ERD50
So the S-class slowed from X to 0 mph in Y feet, the SC went from X to 0 mph in negative Z feet. I don't think you can survive those forces. Anyone want to calculate the G-forces on a 150# occupant in the SC?
Back of the envelope computation of the collision:
Total time in contact = .08 seconds (assumes 6 feet of combined crumple space and an average velocity of 50 MPH. This is a wag, and likely conservative. If we assume both cars are going 60 MPH, then they have x number of seconds to cover the 6 feet of crumple space at a combined speed of 120 MPH. I assumed the average
speed over this entire time time was just 50 MPH).
If, over that .08 seconds the Mercedes goes from 60 MPH to 0 MPH, then the deceleration forces in the Mercedes are 1100 fps^2, or 34 Gs
In the Smart car (60 MPH to -20 MPH) the deceleration forces are 1466 fps^2, or 46 Gs.
Again, just a wag. I'd love to see the instrumentation reading from the dummies in both cars.
The Smart Car benefits form the generous crumple zone provided by the Mercedes. In a Smart car, riding with your feet very close to the front bumper, hitting anything with less crumple space (truck bumper, another Smart Car, a wall) there's just no way to reduce the acceleration experienced by passengers as can be done in a larger vehicle. That intact body with the doors that open looks impressive on camera, but it's not much good if they find your head snapped off your neck and rolling on the floorboards.
[Later edit: Is see Marquette was crunching numbers, too. 6 G's sounds way too low for the occupants of either vehicle. Still, his approach assumes more distance for the Mercedes to "decellerate", which is probably Marquette's way of accounting for the rearward movement of the Smart car while the vehicle is still crunching. This is probably a more accurate model, and would significantly reduce the accleration in the Merc while also driving up the numbers in the Smart car. So, probably reduce my Gs for the Mercedes occupants by 50%, double the numbers for the Smart car.]