Eddie Cooper

Matched-Pair Rollover Impacts of Rollcaged and Production Roof Cars Using the Controlled Rollover Impact System (CRIS)

The authors of this chapter, from a comprehensive text on occupant and vehicle responses in rollovers, report on a study of three rollcaged and three production roof vehicles were exposed to matched-pair rollover impacts using the Controlled Rollover Impact System (CRIS). The CRIS consists of a towed semi-trailer, which suspends and drops a rotating vehicle from a support frame on the rear of the trailer. The authors found that the roof-to-ground contacts were representative of severe impacts in previous rollover testing and real world rollovers. Results showed that the seat-belted dummies measured nearly identical head impacts and neck loads, with or without the rollcage, despite significant roof crush in the production roof vehicles. The peak head accelerations and neck loads were a result of the roof striking the ground and stopping and were not related to roof/pillar deformation. If humans were subjected to these same impact conditions, the rollcaged vehicles would not have protected them. The authors conclude that the CRIS is a very reliable tool to conduct repeatable rollover impacts with controlled dummy positioning.

Repeatable Dynamic Rollover Test Procedure with Controlled Roof Impact

Rollover crash and accident tests identify significant roof-to-ground impacts adjacent to the vehicle occupant as a potential cause of severe injuries. These tests also often provide information on dummy kinematics, as well as vehicle translational velocity, roll rate, and point of impact with the ground. However, there has not been a method to replicate these impact conditions through controlled dynamic rollover testing. In this chapter, from a comprehensive text on occupant and vehicle responses in rollovers, the authors report on a new test device that is repeatable. The tests enables researchers to begin each test with the desired root-to-ground impact conditions as a test input. The test method releases a rotating vehicle onto the ground from the back of a moving semi-trailer. The roll, pitch, and yaw angles, translational and vertical velocities, and roll velocity of the vehicle for the first roof-to-ground interaction is repeatable from test to test. The motion of the vehicle after the first impact is not repeatable, however. In addition to the standard onboard and off-board vehicle documentation, camera coverage from the rear of the semi-trailer is also now available.

Head Excursion of Seat Belted Cadaver, Volunteers and Hybrid III ATD in a Dynamic/Static Rollover Fixture

In rollover accidents, seatbelted occupants sustain a lower fatality rate compared to unbelted occupants, primarily due to lower risk of ejection. However, seat belts do not typically prevent head contact with the vehicle interior during a rollover, due to occupant torso and head excursion. This chapter on head excursion of occupants is from a comprehensive text on occupant and vehicle responses in rollovers. In this chapter, the authors report on a total of 80 excursion tests: 51 tests with a Hybrid III 50th percentile male anthropomorphic test devices (ATD); 18 tests with a cadaver; and 11 tests with two male volunteers. Results indicate that vertical head excursion was minimized with a steep lap belt angle and short webbing length, in tests using a two-point lap belt. Tests using a three-point lap and torso restraint showed that the torso belt reduced vertical head excursion primarily by restricting forward torso rotation. The authors also note that the ATD had less vertical excursion than either the volunteers or the cadavers; while the ATD is a useful tool in testing the effectiveness of restraint systems, it may not fully simulate vertical and lateral head excursion of humans in rollover conditions.

Seat Belt Restraint Evidence Generated in the Presence of Fractured Glass

Physical evidence on the seat belt restraint system is one source of data used by investigators to determine whether or not an occupant was wearing their seat belt during a crash. Evidence of occupant loading on seat belts generated during crash events has been thoroughly researched and is well documented in the literature. However, there is a paucity of data regarding the physical evidence produced when fractured glass is introduced into the restraint system during occupant loading events. The objective of this study is to characterize the physical evidence generated by glass-to-seat belt interaction during low-level impact loading, and compare this evidence with the types of seat belt marks that can be generated inadvertently by accident scene bystanders, emergency responders, and crash investigators. The presence of glass particles in and around the vehicle at the end of a crash event may contribute to the inadvertent generation of physical evidence. Movable side windows composed of tempered safety glass and laminated safety glass were fractured via impactor loading representative of occupant impact. The resulting glass fracture fragments were separated by size using a series of sieves, and the distribution of glass fragments size was quantified. New service-replacement seat belt retractor assemblies (including D-ring, latch plate, anchor, and webbing) were tested using a Seat Belt Load Simulator (SBLS) fixture, which simulates occupant loading by applying a repeatable load pulse to the restraint system. Each retractor assembly was mounted onto the SBLS fixture in a position representative of belt routing when installed in a vehicle. A repeatable lap-shoulder belt stroke pulse, representative of low-level restraint loading and consistent in magnitude and duration with loads produced during rollover, was applied using the SBLS with glass fragments of varying sizes introduced onto the webbing surface adjacent to the D-ring and latch plate surfaces. Additional test series were run to investigate the types of physical evidence generated in the presence of glass under non-crash loading scenarios. These scenarios included the extraction of webbing with glass fragments present adjacent to the D-ring and latch plate, extraction of webbing over glass fragments captured or fixed in a window seal, and the compression of webbing with various sizes of glass fragments interposed between the webbing and a reaction surface. Documentation of each restraint system was performed post-test. Seat belt loading events that occurred in the presence of fractured safety glass produced characteristic markings on the restraint system hardware and webbing. The tests conducted to examine non-crash loading evidence generated in the presence of fractured safety glass revealed markings on the restraint system that differed from those generated in a simulated loading event. Language: en