Roof Crush

Roof CrushME 8020

Siddhesh Ozarkar – fr8695

FMVSS No. 216 – ROOF CRUSH• FMVSS No. 216 seeks to reduce deaths and serious

injuries resulting from the roof being crushed and pushed into the occupant compartment when the roof strikes the ground during rollover crashes.• The standard currently applies to passenger cars, and

to multipurpose passenger vehicles, trucks and buses with a GVWR of 2,722 kilograms (6,000 pounds) or less.

SIGNIFICANCE OF ROOF CRUSH & IT’S CRITERIA• The standard requires that when a large steel test plate

is placed in contact with the roof of a vehicle and then pressed downward, simulating contact of the roof with the ground during a rollover crash, with steadily increasing force until

1. A force equivalent to 1.5 times the unloaded weight of the vehicle is reached

2. The distance that the test plate has moved from the point of contact must not exceed 127 mm (5 inches).

SIGNIFICANCE OF ROOF CRUSH ANALYSIS• Due to the complex nature of a rollover event and the

particularized effect of each element of the comprehensive and systematic approach taken by the agency to address these crashes, each element addresses a specific segment of the total rollover problem.

ROOF CRUSH ANALYSIS FOR PICK UP TRUCK- CHEVROLET SILVERADO• Modelling and cleanup of meshed truck model

Surface Model of TruckCleaned Meshed Model of Truck

Roof Crush Analysis Before Condition After Condition

Before Condition

After Condition

The effect of roof crush can be seen going though the panels and reinforcing members of the vehicle.

Design of Experiments (What If study) Outer Door Panels

Outward bulging of External Door Panels

What If Study Solution: 1. Use of High Strength Steel for structural Members shown

Max. Deflection: 142mm

Total Energy of Truck• As expected the total energy

shows a spike in the beginning during the occurrence of full contact.

• The total energy then is gradually a seen to be increasing.

Force vs DisplacementTruck Mass 1.5Tonne =1360kgWeight = 13600 N1.5*Weight = 20400N

Force Boundary

Displacement Boundary

Failed Structure zone

Failed Structure zone

Failed Structure zone

Pass Structure zone

ROOF CRUSH ANALYSIS FOR SEDAN CAR: DEFORMATION• Modelling and cleanup of meshed truck model

Roof Crush Analysis Before Condition After Condition

Before Condition

After Condition

Air Bag Deployed on Roof Impact

STRUCTURAL PERFORMANCE OF CAR AT SIMULATION END

Normal StructureA-B Pillar Displacement = 144 mmRoof Cross Member Displacement= 48mm Buckling Observed

What if Study: Use of DP 600 for structural Members

Total Energy of Car

Force vs Displacement

Failed Structure zoneFailed Structure zone

Pass Structure zone

Conclusion• The models of the truck and the car both satisfy the

criteria of the FMVSS 216.• Structural improvement is possible by utilizing high

strength DP- Steel properties in the structural members.