Roof Crush Analysis

Structural analysis solutions for body chassis powertrain and component applications capabilities applications linear nonlinear dynamics durability test correlation composites component strength roof crush nvh part fatigue.

Roof crush analysis.

Objective of the test roof crush is the failure and displacement of an automobile roof into the passenger compartment during a rollover accident. Each case was evaluated against the deformation patterns observed from the previous analysis. Material approach is preferred over the geometric approach due to space constraints in the passenger compartment as well as weight limitations. With the material and property cards assigned the free nodes and free masses as well as unattached springs and beams are removed from the model.

Used for quasi static roof crush analysis. Quasi static roof crush analysis was carried out on a car roof by a more or less rigid contact body with a flat surface with low velocity i e. Rollover test and nass case analysis nhtsa june 1992. One of the tests used in occupant safety analysis is a roof crush test.

The acceleration induced by the tripping motion itself may be sufficient to eject unbelted occupants before rollover habberstad 1986. A and b pillars tended to remain virtually straight. The recently released nhtsa study roof crush analysis using 1997 2001 nass case review which has been in the works for nearly four years reviewed nass rollover crashes in an effort to determine whether roof deformation patterns identified in an earlier agency study were still valid for current vehicle designs see upgraded rollover roof crush protection. Static and it was simulated in ls dyna shown in fig.

The reason for such low roof crush resistance is the reduced model which does not include all of the components of the biw to offer proper geometric resistance to the impactor displacement. It is used to evaluate how a car will deform during a rollover accident. Vehicle damage is mostly influenced by vertical velocity not roll rate or lateral velocity. The analysis procedure consisted of examining the case summary crash diagrams and photographic documentation to observe general roof damage patterns.

216 fmvss 216 first published in 1971 specified the test requirements and configurations of roof crush process. Fig 16 swr versus platen displacement for honda accord and lwv in iihs roof crash test. Roof crush simulation federal motor vehicle safety standard no. The relationship between injury levels and intrusion or roof crush has been statistically established but the mechanism has been thought sometimes to be somewhat obscure.