Presentation on theme: "Vehicle Roof Structure Design Can Significantly Reduce Occupant Injury"— Presentation transcript:
1 Vehicle Roof Structure Design Can Significantly Reduce Occupant Injury Presented by: Susie BozziniSusie 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
2 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.Types of rollover Events
3 Frequencies of different Rollover Types: Trip-Over and Flip-Over = 72% of all Rollovers
4 Ramp Rollover Impact Parameters vs. Lateral Rollover Impact Parameters Ramp Rollover TestLateral Rollover TestRoll Rate (Test)175 deg/sec at near side contact244 deg/sec at near side contactPitch 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 turn145 degrees, more than 1/4 turn – injurious rollover are~ more than 4 quarter turnsPitch Angle (Test)18 degrees,front/nose UP10 degrees,front/nose DOWN
5 Comparison of Trip-Over and Flip-Over Frequency and Injury Level Count/Frequency %%Not Injured% MAIS1% MAIS 2-4% MAIS 5/6Total Trip-Over Rollovers328/59.8%11.6638.48.680.82Total Flip-Over Rollovers66/11.7%1.919.172.290.214 times as many MAIS 2-4 and MAIS 5/6 in Trip-overs vs. Flip-overs
6 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
7 Dynamic testing results of an early model Ford Ranger Background information 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.
8 The test was a one roll event 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.
12 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.
13 1993 Jeep Grand Cherokee JRS Testing with and without HALO™
14 Rollover Result in Lateral Test Method – Significant Far Side A-Pillar CrushProduction SUV roof crush v. roll angle
15 Rollover Result in Lateral Test Method – With HALO™ minimized Far Side A-Pillar CrushFigure 12. – SUV with HALO™ roof crush v. roll angle
16 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.
17 Rollover of a Toyota Hilux Dual Cab with HALO™ in Namibia.
18 HALO™ Single Cab Development 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.Confidential and Proprietary - Safety Engineering International5949 Hollister Ave. Ste A Goleta, CA
19 HALO™ Single Cab Development Single Cab Rear Roll Hoop design attached to Cab only
20 HALO™ Single Cab Development Internal Reinforcements in Single Cab Trucks
21 CONCLUSIONSTrip-over accidents represent 60% of rollovers and about 25% of all US based Catastrophic Injuries and Fatalities.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.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.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.This distribution of the loads across the entire vehicle cab significantly reduces roof collapse, preventing occupant injury.
22 ACKNOWLEGEMENTS Thank you Questions? The Authors would like to thank Friedman Research Corporation for their assistance with the data in this paper.Thank youQuestions?