Search Results

Bumpers have lost their important functions of crash load isolation and inter-vehicle compatibility. Occupant compartment protection has been shifted to collapse of surrounding structures, with vehicle inoperability and occupant injury not unusual after a 50 km/h barrier impact. For higher speed vehicle and occupant survivability, a larger crash stopping distance is needed - provided by bumpers extended by radar sensing of need just before the crash. The hydraulic extended bumper was first developed by Professor James Ryan, giving vehicle driveability after a 40 km/h barrier crash, and further developed worldwide in the Experimental Safety vehicle programs, but unfortunately never developed for the commercial market. Our current work is to demonstrate the potential of compartmented airbag bumper systems inflated just before the crash to cover 1 square meter on the crash surface.

A frontal barrier crash at 48.5 km/h and a moving rigid barrier crash at 48.5 km/h into the side of a stationary car have been carried out at the Insurance Institute for Highway Safety's Vehicle Research Center, with the car having frontal then side preinflated airbag bumpers. This is a preliminary simulation of an airbag bumper system with the needed airbag inflation triggered by radar sensing of the approaching threat. The frontal airbag bumper had a high pressure airbag at 221 kPa and 23 cm thick imbedded on the outboard side of a low pressure airbag at 20 kPa whose inboard side was against the original car bumper, with a thickness of an additional 61 cm at the center line, for a combined thickness of this prototype airbag bumper of 84 cm. The low pressure airbag ruptured as expected in the frontal crash, with the airbag bumper absorbing about 19 percent of the energy of the crash due to excessive penetration into frontal structures.

The non-uniformity of temper of 27 motor vehicle door windows as measured by the polarization method is presented, illustrated by two photographs of windows between crossed polarizers. The tempered glass fracture characteristics of 11 Geo Prism door windows are illustrated by two video frames of the windows after fracturing by door deformation slowly applied at bumper level. The speed of some moderate sized fragments was measured to exceed 60 km/h, due to strain relief rather than contact by an intruding object. Glazing history is briefly summarized, with our support of the NHTSA conclusion that more than 1300 lives per year could be saved cost effectively by replacing tempered glass by an “advanced glazing.”

We are seeking to test and adapt successful devices for child crash protection from outside the United States not now used here. Test results and possible problems are presented for a transverse infant bed, a toddler backward facing seat, and an older child booster seat with back and head supports (from Kilppan, Sweden), and the Australian “Sit-Safe” design, an inexpensive belt to go between the shoulder strap and the lap belt to insure that the shoulder belt does not touch the child's neck. We have also tested an inflated pad alternative to the upper back of the front seat bulge passive restraint of DeRampe (France) to reduce knee contact - leg straightening - body vaulting which contributes to ejection of unrestrained people from the back seat. And we are testing plastic coated side glass to explore extending the anti-lacerative glazing advance of Saint-Gobain Vitrage (France) to the even more significant potential reduction of ejection.

Ejection is a major problem in motor vehicle safety, with some 43,000 people per year being ejected from passenger cars, with some 6000 of these killed. About half of these people killed are ejected through glazing areas. The November, 1983, amendment of Federal Motor Vehicle Safety Standard 205 now allows the use of glass-plastic glazing anywhere in a motor vehicle. Our study has explored the “safety net” implications of glass-plastic glazing, produced by Saint-Gobain Vitrage, 3M, and DuPont for the anti-laceration implications but tested in our study for reducing ejections by controlled deformation after the glass layer or layers break. The inner plastic layers holds the broken pieces of a tempered side glazing together enough to reduce adult head partial ejection in side impacts, with the plastic layer trimmed to the glazing edges.

1983 ejection statistics are reviewed; half of the passenger car ejections, some 36,000 people of whom 5,346 died, are through glazing areas. Previous work has shown the remarkable strength of thin plastic coatings, developed for windshield anti-laceration applications, when applied to the inside of tempered glass side windows, in reducing ejection. In the present work, two tests were made, each with the NHTSA Moving Deformable Barrier (MDB) at 39 mph and all four wheels turned at 26 degrees, striking a stationary Volkswagen Rabbit in a perpendicular impact. The Alfred I. DuPont de Nemours Company provided the plastic coating on tempered glass side windows. The plastic layer extended beyond the sides and top of the glass to be wrapped around steel strips bolted to the window frame. On vehicle impact, the tempered glass broke, but the pieces were held in place by the plastic layer, which then deformed outward as a “safety net” with head contact.

About one fourth of the occupant deaths in passenger cars in the United States involve either complete or partial ejection. Approximately one half of these ejections are through glazing areas. This paper presents research results which demonstrate the potential of glass-plastic glazing to significantly reduce ejections through motor vehicle windows. Four passenger car and four light truck and van rollover experimental crashes were conducted. All the vehicles had glass-plastic front side window glazing. One of these included the improved glazing with a movable encapsulated “offset T-edge” design. Two in addition had glass-plastic windshields. Even with glass breakage and window frame distortion, the glass-plastic glazings maintained their “safety net” ejection reduction function. Laboratory dummy drop and sled tests of the movable glass-plastic glazing side windows are reported.

The injury reducing effectiveness of child safety seats in frontal crashes was evaluated, based on 36 frontal or oblique sled tests run with two or more GM three-year-old dummies in the simulated passenger compartment of a car. Unrestrained, correctly restrained and incorrectly restrained dummies were tested at the range of speeds where most nonminor injuries occur (15-35 mph). Accident data from NHTSA files were used to calibrate a relationship between the front-seat unrestrained dummies' HIC and unrestrained children's risk of serious head injuries; also between torso g's and the risk of serious torso injuries. These relationships were used to predict injury risk for the restrained children as a function of crash speed and to compare it to the risk for unrestrained children. The sled test analysis predicted that the 1984 mix of correctly and incorrectly used safety seats reduced serious injury risk by 40 percent relative to the unrestrained child, in frontal crashes.

The facial laceration test has been proposed as an addition to the dummy injury criteria of Federal Motor Vehicle Safety Standard 208. To better understand laceration conditions as they actually occur, three road crashes of increasing severity, all involving facial laceration by the broken (cracked) windshield and one involving partial ejection, have been simulated physically and analytically. The physical simulations used vehicle test bucks, the Hybrid III head with the chamois facial coverings of the facial laceration test, and a piston - constrained Head Impactor. Computer simulations of the three crashes were also carried out using the CALSPAN 3D “CVS” and the 2D “DRISIM” computer programs. The computer simulations provide insight into the effective mass of the head and body on windshield contact, and the forces, velocities, and accelerations involved.