David J. Porta

Airbag-induced eye injuries: a report of 25 cases

OBJECTIVE To acquire a better understanding of airbag-induced eye injuries, 25 cases are reviewed and an attempt is made to identify the causal mechanisms associated with each injury. DESIGN AND METHODS The National Highway Traffic Safety Administrations National Accident Sampling System for the years 1984-1994 was accessed to identify automobile accidents that included airbag deployment and injury to the ocular region. The search provided 25 such cases with detailed studies of the accident scene and medical records of the injuries. The cases were comprehensively reviewed to determine the casual mechanisms associated with each group of injuries. RESULTS The study determined that the injuries range from mild corneal abrasions to retinal detachment. Causation for each injury was determined and is detailed. The injuries were grouped according to location within the ocular region, and the distribution is shown. CONCLUSIONS Most of the injuries were induced by impact with the fully deployed airbag, but the more severe ocular trauma resulted from the actively deploying airbag striking the occupant. Thus, ocular trauma from airbags can occur in very minor impacts. Additionally, the left eye seemed more vulnerable to injury than the right. Nontethered airbags have greater inflation distances that tend to increase the probability of injury. External parameters that may also increase the severity of eye injury include an unfastened seat belt, sitting too close to the steering wheel, or wearing glasses.

Non-censored rib fracture data during frontal PMHS sled tests

ABSTRACT Objective: The purpose of this study was to obtain non-censored rib fracture data due to three-point belt loading during dynamic frontal post-mortem human surrogate (PMHS) sled tests. The PMHS responses were then compared to matched tests performed using the Hybrid-III 50th percentile male ATD. Methods: Matched dynamic frontal sled tests were performed on two male PMHSs, which were approximately 50th percentile height and weight, and the Hybrid-III 50th percentile male ATD. The sled pulse was designed to match the vehicle acceleration of a standard sedan during a FMVSS-208 40 kph test. Each subject was restrained with a 4 kN load limiting, driver-side, three-point seatbelt. A 59-channel chestband, aligned at the nipple line, was used to quantify the chest contour, anterior-posterior sternum deflection, and maximum anterior-posterior chest deflection for all test subjects. The internal sternum deflection of the ATD was quantified with the sternum potentiometer. For the PMHS tests, a total of 23 single-axis strain gages were attached to the bony structures of the thorax, including the ribs, sternum, and clavicle. In order to create a non-censored data set, the time history of each strain gage was analyzed to determine the timing of each rib fracture and corresponding timing of each AIS level (AIS = 1, 2, 3, etc.) with respect to chest deflection. Results: Peak sternum deflection for PMHS 1 and PMHS 2 were 48.7 mm (19.0%) and 36.7 mm (12.2%), respectively. The peak sternum deflection for the ATD was 20.8 mm when measured by the chest potentiometer and 34.4 mm (12.0%) when measured by the chestband. Although the measured ATD sternum deflections were found to be well below the current thoracic injury criterion (63 mm) specified for the ATD in FMVSS-208, both PMHSs sustained AIS 3+ thoracic injuries. For all subjects, the maximum chest deflection measured by the chestband occurred to the right of the sternum and was found to be 83.0 mm (36.0%) for PMHS 1, 60.6 mm (23.9%) for PMHS 2, and 56.3 mm (20.0%) for the ATD. The non-censored rib fracture data in the current study (n = 2 PMHS) in conjunction with the non-censored rib fracture data from two previous table-top studies (n = 4 PMHS) show that AIS 3+ injury timing occurs prior to peak sternum compression, prior to peak maximum chest compression, and at lower compressions than might be suggested by current PMHS thoracic injury criteria developed using censored rib fracture data. In addition, the maximum chest deflection results showed a more reasonable correlation between deflection, rib fracture timing, and injury severity than sternum deflection. Conclusions: Overall, these data provide compelling empirical evidence that suggests a more conservative thoracic injury criterion could potentially be developed based on non-censored rib fracture data with additional testing performed over a wider range of subjects and loading conditions.

A PNEUMATIC AIRBAG DEPLOYMENT SYSTEM FOR EXPERIMENTAL TESTING

This paper examines an originally designed airbag deployment system for use in static experimental testing. It consists of a pressure vessel and valve arrangement with pneumatic and electric controls. A piston functions like a valve when operated and is activated pneumatically to release the air in the tank. Once released, the air fills the attached airbag. The leading edge velocity can be controlled by the initial pressure in the tank, which can range up to 960 kPa. Three different test configurations were studied, which resulted in leading edge deployment speeds of approximately 20 m/s, 40 m/s, and 60 m/s. In experiments using this system, seven types of airbags were tested that differed in their material, coating, and presence of a tether. Data for each series of tests is provided. In addition to cost savings, the primary advantage of this system is its ability to quickly change the internal pressure. For the covering abstract see IRRD 893297.