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Safety Engineering International > SEI RESEARCH PAPERS


Significant research and development went into the design of the HALO™ ROPS. The following papers describe that process and can give you a better understanding of how and why the HALO™ ROPS works so well to prevent rollover roof intrusion that can cause injury to the occupants of the vehicle.

1. Comparing Vehicle Rollover Crash Test Rigs: JRS vs. DRoTS International Crashworthiness Conference, August 25-28, 2014

“To date, there is no standard vehicle rollover crashworthiness test procedure accepted by any regulatory authority that is capable of providing repeatable results in a similar manner to frontal and side impact crash tests. It appears that rigs based on the principles of the Jordan Rollover System (JRS) may be capable of replicating in a repeatable manner both the vehicle kinematics and the roof deformation for typical rollover scenarios. However, the capability of such rigs to provide consistent results in repeated tests conducted within different facilities, i.e., reproducibility, has not yet been proven. This research paper investigates the reproducibility of testing conducted with a second evolved version of the JRS, namely the UNSW JRS, which was developed for the University of New South Wales in co-operation with US researchers. Also, the paper describes the test setup requirements along with some difficulties that were experienced during the test rig’s calibration. Reproducibility of testing with the UNSW JRS was assessed by replicating a baseline test previously performed at the University of Virginia using the Dynamic Rollover Test System (DRoTS), which is a rig with the same functionality as the UNSW JRS. The test with the UNSW JRS rig was performed under the same initial conditions and with the same type/model of vehicle used in the baseline test. Promising results were obtained from the comparison of the two tests independently carried out with the UNSW JRS rig and the UVA DRoTS rigs. The rigs have demonstrated to be potentially capable of performing reproducible rollover crash tests. This finding is a step toward a potential adoption of such rigs into a reliable dynamic rollover testing protocol for assessing vehicle crashworthiness.”

2. Reliability and Relevance of Rollover Occupant Injury Potential Tests International Crashworthiness Conference, August 25-28, 2014

“From as early as 1965, US auto manufacturers have been researching means to reduce rollover injuries and fatalities. Dynamic rulemaking in 1970 was rejected by industry and in 1973 the Department of Transportation issued a static roof crush test rule proposed by the industry. That rule stood for 35 years until 2009 when the strength requirement was doubled and research was initiated into dynamic rollover means of testing. This paper reviews the literature, examines and compares the frequency and injury potential of rollover accident modes. Two modes are represented in test methodology by the lateral roll over (corresponding to trip-overs) and the ramp (or corkscrew) roll over (corresponding to flip-overs). The energy and impact orientation of the typical ramp rollover tests are dramatically more violent and not comparable to the results of lateral tests conducted with a real-world protocol representing 95% of serious injury rollovers.”

3. Integrating OEM Vehicle ROPS to Improve Rollover Injury Probability International Crashworthiness Conference, August 25-28, 2014

“Geometry is a subset of styling and almost all cars have the same generic roof geometry. Studies have shown, however, that geometry plays a big role in the depths of roof crush for a given rollover impact scenario. However, consumers are misled by a rollover propensity rating on safety charts with dynamic frontal, front offset, side and rear crashworthiness ratings. Rollover crashworthiness has and continues to have the lowest priority in sales potential with consumers although 3% of accidents result in 30% of fatalities. Off-road fleet customers of work vehicles with high rollover fatality rates see the situation differently and equip their vehicles with aftermarket rollover occupant protection systems (ROPS). This paper compares the styling and rollover performance of the original designs, the same vehicles with a patented external ROPS (HALOTM) and as modified with an OEM version of the same patent.”

4. Vehicle Roof Structure Design Can Significantly Reduce Occupant Injury International Crashworthiness Conference, August 25-28, 2014

“Vehicle design has been driven by sales and marketing factors for many years, with a few exceptions like the brutish looking Hummer Sport Utility Vehicle (SUV) which was marketed for its structural safety. While it’s partially true for public customers, consumers of work trucks commercial operations like in the oil, gas and mining industry are a large fleet consumer for dual cab transportations and an even larger segment for simple single cab work trucks. These vehicles are designed to meet the minimum specifications for safety equipment and structural tolerances and therefore can be inadequate in various crash modes. Most manufacturers focus on sales in the US where regulations are design determinants, but 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. This paper focuses on the design and performance of these work trucks and the means by which rollover safety can be measured and significantly improved.”

5. A Study of Rollover Occupant Injury Mitigation Using Dynamic Testing to Evaluate Alternative Protection Systems Society of Petroleum Engineers Conference, June 26 – 27, 2013

“Since the onset of automotive safety awareness over 60 years ago the only rollover protection solution to be widely acknowledged and used in the E & P Industry has been the traditional internal roll cage. These traditional roll cages have become out-of-date and in recent testing are shown to be ineffective at the A-Pillar and windshield header.”

6. Commercial, Police, and Military Vehicle Rollover Protection and Evaluating the Effectiveness of Geometry and Retrofit Rollover Testing International Crashworthiness Conference, September 22-24, 2010

“Rollover crashes cause more than 10,000 fatalities and nearly 30,000 serious injuries per year in the U.S. alone. This is due to the fact that the vast majority of vehicles, including commercial, police, and military, lack the roof strength to preserve occupant survival space and protect their occupants in a rollover. Recent statistical and epidemiological studies have shown a significant relationship between roof crush and injury. This rollover occupant protection problem is well known to industries with large vehicle fleets; until now, this problem has eluded solution. Within these various industries a wide variety of rollover occupant protection systems (ROPS), both internal and external, have been designed, purchased, manufactured, installed, and maintained locally with little expert consultation. A wide variety of designs have emerged with an alarming variance in “assumed” crashworthiness. Couple this alarming trend with the risk of rendering the existing occupant protection features (e.g., airbags) ineffective, which has resulted in vehicles with inadequate crashworthiness. This paper describes how rollover damage to a vehicle with a weak roof and the resulting reduction of occupant headroom can be minimized to an inconsequential amount using an innovative externally retrofitted rollover load distribution device. This system was based on an understanding of road crash data, empirical evidence, and innovative state of the art testing and analysis to provide effective external ROPS structures for the commercial, police and military fleets.”

7. ROLLOVER PROTECTION – A Meaningful & Effective Solution Society of Petroleum Engineers Conference, April 12-14, 2010

“Rollover crashes remain over represented in land transportation around the world and in particular, the Oil and Gas industry, (OGP) when compared to other crash categories. The realities of this crash type is that within the USA alone it represents one in 33 car crashes each year, but it claims more than three of every ten lives lost on the nation’s highways – 10,000 fatalities a year! As a crash type it is now responsible for more than a quarter of a million injuries, according to the National Highway Traffic Safety Administration (NHTSA) (NHTSA, 2009) …This paper describes how roof crush intrusion and intrusion speed into the occupant compartment can be minimized to an inconsequential amount using innovative design to externally retrofitted roof strengthening systems based on an understanding of road crash data, empirical evidence, and innovative state of the art testing and analysis to provide effective external ROPS structures for the OGP.”

8. Vehicle Roof Geometry and its Effect on Rollover Roof Performance Enhanced Safety of Vehicles Conference, June 15–18, 2009

“The Jordan Rollover System (JRS) provides a realistic, highly controlled, repeatable dynamic test of vehicle roof crush performance under typical rollover conditions [1],[2]. The principal use thus far has been in comparing vehicles’ roof crush and injury potential performance in one and two roll events. Because the JRS directly measures the force between the roof and the ground during touchdown, it can be used to measure, assess and optimize occupant protection by adjusting roof geometry, roof structural design and material strength and elasticity, for the least cost and weight. …These tests led to the conclusion that a geometry change in the roof to minimize the difference in radius across the roof would reduce the degree to which the far side of a less strong roof had to lift the vehicle as it rolled beyond 180º. …These results were confirmed in JRS testing of current production passenger cars and SUV vehicles and with a HALO – High Attenuation Load Offset retrofit kit for SUVs.”
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