MGA On-Line for New Roof Crush NPRM
| FMVSS 216 – Roof Crush Resistance is a government-regulated safety standard established to “reduce deaths and injuries due to the crushing of the roof into the occupant compartment in rollover crashes”. In August 2005, the National Highway Traffic Safety Administration (NHTSA) published an initial Notice of Proposed Rulemaking (NPRM) with respect to improving FMVSS 216. An NPRM is used by NHTSA to obtain feedback and comments from automotive manufacturers, suppliers, and the general public in regard to proposed regulation changes. On January 23, 2008, NHTSA issued a supplemental NPRM relative to the FMVSS 216 standard. MGA has been conducting the proposed test method for the last few years. Currently, FMVSS 216 requires all vehicles with a Gross Vehicle Weight Rating (GVWR) up to and including 2,722 kg (6,000 lbs) to be tested. For compliance, a static test is conducted using a defined load platen which is used to crush the vehicle roof (on either front side) at a downward specified angle and record the load/displacement. The criterion that is required to meet FMVSS 216 is that the total load obtained from the platen must reach 1.5 times the UVW (Unloaded Vehicle Weight) or 22,240 N, whichever is less, before reaching 127 mm of platen travel. Regarding the latest NPRM, the proposed criteria changes are as follows; 1) the required load increases to 2.5 times the UVW and is applicable to vehicles up to a GVWR of 10,000 lbs, and 2) an un-instrumented Hybrid III 50th percentile test dummy is seated inside the vehicle to determine if and when contact is made between the interior roof and the top of the dummy’s head (no contact is allowed prior to reaching 2.5 times UVW load). In addition, the vehicle fixturing procedure has also been modified by only allowing the body to be rigidized using four test stands as opposed to the previous method of using chains and binders. Also, the latest NPRM specifies successive tests (2 loadings total) on each front corner of the same vehicle. MGA-Michigan’s Structural Laboratory in Troy, Michigan has a roof crush system designed to meet both the new and recently proposed requirements. The system is designed with a number of features including the following:
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