Vehicle Roof Structure Design Can Significantly Reduce Occupant

Injury

Susie Bozzini*, Donald Friedman** and Raphael Grzebieta***

*Safety Engineering International Goleta, CA, USA** Center for Injury Research, Santa Barbara, USA*** TARS, University of New South Wales, Australia

Presented by: Susie Bozzini

Types of rollover Events

This paper focuses on the design and performance of OGM work trucks and the means by which rollover safety can be

measured and significantly improved.

Outside the US, there are some times little or no minimum safety design regulations. The Mitsubishi Triton and the Toyota Hilux 4 and 2 door pickup vehicles, all of which are NOT sold in the US, require structural reinforcement for safe operation in these non-ordinary environments.

Frequencies of different Rollover Types:Trip-Over and Flip-Over = 72% of all Rollovers

Ramp Rollover Impact Parameters vs. Lateral Rollover Impact Parameters

Parameter: Ramp Rollover Test Lateral Rollover Test

Roll Rate (Test)175 deg/sec at near side

contact244 deg/sec at near side

contact

Pitch Rate (Test)15 deg/sec, oscillating from

0 - front/nose upConstant at 10 deg (+/-2)

Roll Angle (Test)105 degrees, a little more

than 1/4 turn

145 degrees, more than 1/4 turn – injurious rollover are ~ more than 4 quarter turns

Pitch Angle (Test)

18 degrees, front/nose UP

10 degrees, front/nose DOWN

Comparison of Trip-Over and Flip-Over Frequency and Injury Level

Count/Frequency

%

% Not

Injured % MAIS

1% MAIS

2-4% MAIS

5/6

Total Trip-Over

Rollovers328/59.8% 11.66 38.4 8.68 0.82

Total Flip-Over

Rollovers66/11.7% 1.91 9.17 2.29 0.21

4 times as many MAIS 2-4 and MAIS 5/6 in Trip-overs vs. Flip-overs

Trip-Over Test MethodKey components of the Jordan Rollover System (JRS): (1) vehicle, (2) cradle/spit mount, (3) moving roadbed, (4) support towers, (5) coupled pneumatic -roadbed propulsion and roll drive

Background information - 1998 Ford RangerFrom our years of experience in rollover accident analysis, the deformation pattern of a typical single or extended cab LTV after a rollover event with 10 degrees forward pitch are shown in the pre and post testing photos in the next section. The test was performed on the Jordan Rollover System on a 1998 Ford Ranger. As has been typical of our previous finding of forward pitch rollovers, the A-Pillar, windshield header, and roof rail area over the passenger compartment collapsed and significantly intruded into the occupant survival space. A synopsis of the test is supplied including tables of the test parameter initial conditions, the vehicle specifications, and the test results at the measured locations.

Dynamic testing results of an early model Ford Ranger

The test was a one roll event. The roll was planned with a roadbed speed of 20 mph and a 145 degree contact angle. The roadbed speed corresponds to a 250 degree per second roll rate for the vehicle. A Denton Hybrid II 50th percentile male crash dummy was used; however the head was removed and replaced with padding in order to simulate the shoulder loading. The dummy was located “out of position;" leaning towards the passenger side approximately 45°. The test weight of the vehicle was 3,869 pounds.

1998 Ford Ranger Extended Cab Test Results

Toyota Hilux Single Cab – Safety Devices ROPS

The HALO™ patent provides a formula for the shape (the geometry) of the roof and its attachment to the pillars. It covers both OEM and an aftermarket accessory attachment. The device’s performance has been validated using the Jordan Rollover System (JRS) rollover crash test rig and dolly rollover tests.

1993 Jeep Grand Cherokee JRS Testing with and without HALO™

Production SUV roof crush v. roll angle

Rollover Result in Lateral Test Method – Significant Far Side A-Pillar Crush

Figure 12. – SUV with HALO™ roof crush v. roll angle

Rollover Result in Lateral Test Method – With HALO™ minimized Far Side A-Pillar Crush

Further validation of the aftermarket version HALO™ on the Triton dual cab was demonstrated by a field rollover crash in Mexico and a Toyota Hilux Dual Cab in Namibia.

Rollover of a Toyota Hilux Dual Cab with HALO™ in Namibia.

HALO™ Single Cab Development

Confidential and Proprietary - Safety Engineering International 5949 Hollister Ave. Ste A Goleta, CA 93117 805-895-5192

The HALO™ for the Toyota Hilux and Isuzu KB250 Single Cabs were designed using the same methodology as the Dual Cab and Sport Utility Vehicle to protect front seat occupants. The Single Cab design adds reinforcements to the B-pillars and a rear panel and roll hoop to substitute for the rear compartment structure of the Dual Cab design.

Single Cab Rear Roll Hoop design attached to Cab only

HALO™ Single Cab Development

Internal Reinforcements in Single Cab Trucks

HALO™ Single Cab Development

 1. Trip-over accidents represent 60% of rollovers and about 25% of all US based

Catastrophic Injuries and Fatalities.

2. From the FEM analysis and the crash investigations, the HALO™ system is effective in reducing roof crush over the front seat occupants, particularly at the A-pillar location.

3. In effect the HALO™ system changes the roof geometry such that the amount of load the roof is subjected to during a rollover crash is reduced substantially.

4. Rounded roof shapes, where the vehicle rolls about the major radius, allow the vehicle to roll like a cylinder and will have the least point loading on the roof structure, preventing a single pillar or header from taking the majority of the load.

5. This distribution of the loads across the entire vehicle cab significantly reduces roof collapse, preventing occupant injury.

CONCLUSIONS

ACKNOWLEGEMENTSThe Authors would like to thank Friedman Research

Corporation for their assistance with the data in this paper.

Thank you

Questions?