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Technical Paper

A Finite Element and Multi-body Model of the Pregnant Female Occupant for the Analysis of Restraint Effectiveness

2003-03-03
2003-01-0157
A finite element model of a 7-month pregnant uterus was created and integrated into a multi-body human model. The uterine model contains 11,632 elements and 16,335 nodes. The pregnant occupant model was validated using known abdominal response corridors. Unrestrained, 3-pt belt, and 3-pt belt plus airbag tests were simulated at speeds ranging from 13 kph to 55 kph. Peak uterine strain was found to be a good predictor of fetal outcome (R2= 0.85). The strain in the uterine wall exceeded 60%, sufficient to cause placental abruption, in simulations of no restraint at 35 kph and 3-pt belt tests at 45 kph and 55kph. These tests represent a greater than 75% risk of adverse fetal outcome. For matched tests at 35 kph, strains of 60.8% for the unrestrained occupant, 52.6% strain for the 3-pt seatbelt and only 33.0% strain for the 3-pt seatbelt and airbag combination were recorded.
Technical Paper

A Nonlinear Finite Element Model of the Eye With Experimental Validation for the Prediction of Globe Rupture

2002-11-11
2002-22-0005
Over 2.4 million eye injuries occur each year in the US, with over 30,000 patients left blind as a result of the trauma. The majority of these injuries occur in automobile crashes, military operations and sporting activities. This paper presents a nonlinear finite element model of the eye and the results of 22 experiments using human eyes to validate for globe rupture injury prediction. The model of the human eye consists of the cornea, sclera, lens, ciliary body, zonules, aqueous humor and vitreous body. Lagrangian membrane elements are used for the cornea and sclera, Lagrangian bricks for the lens, ciliary, and zonules, and Eulerian brick elements comprise the aqueous and vitreous. Nonlinear, isotropic material properties of the sclera and cornea were gathered from uniaxial tensile strip tests performed up to rupture. Dynamic modeling was performed using LS-Dyna.
Technical Paper

Eye Injury and Orbital Fracture Patterns in Frontal Automobile Crashes

2003-03-03
2003-01-0511
The purpose of this study was to investigate eye injuries and orbital fractures resulting from frontal automobile crashes and to determine the effects of frontal airbags. For this two part study, cases in NASS were selected from the years 1993 through 2000 that include drivers and front seat occupants only, while excluding ejected occupants and rollovers. In addition, only frontal impacts were considered, which are defined as having a primary direction of force (PDOF) of 11, 12, or 1 o'clock. Eye injuries in the NASS database were identified using the current AIS injury codes. An analysis of the cases indicates that 3.1% of occupants exposed to an airbag deployment sustained an eye injury, compared to 2.0% of those occupants not exposed to an airbag deployment. Moreover, there was a significant increase in the risk of corneal abrasion for occupants exposed to an airbag deployment (ρ = 0.03).
Technical Paper

Frequency Content Analysis and Filter Class Selection for the Small Female Instrumented Upper Extremity

2002-03-04
2002-01-0806
Although filter class specifications have been defined for most anthropomorphic test devices, no recommendation exists for the instrumented upper extremity. A three-part study was performed to determine the best channel filter class (CFC) to use for the instrumented upper extremity. By analyzing frequency content of signals from accelerometers and load cells, filtering data through three of the four possible CFC's to compare effects on the signals, and performing an injury comparison between cadaver data and the filtered load cell data, CFC 600 was chosen and recommended as the optimum filter class to use for upper extremity testing.
Technical Paper

Incidence of Severe Upper Extremity Injuries and Minor Skin Injuries In Frontal Automobile Crashes

2003-03-03
2003-01-0513
The purpose of this study was to investigate severe upper extremity injuries and minor skin injuries resulting from frontal automobile crashes and to determine the effects of frontal airbags. The National Automotive Sampling System database files from 1993 to 2000 were examined in a study that included 25,464 individual cases that occurred in the United States. An analysis of the cases indicated that occupants exposed to an airbag deployment were statistically more likely to sustain a severe upper extremity injury (2.7%), than those occupants not exposed to an airbag deployment (1.6%) (p=0.01). In particular, 0.7% of occupants exposed to an airbag deployment sustained a severe upper extremity injury specifically from the airbag. In addition, when in crashes with an airbag deployment, older occupants were at a higher risk for severe upper extremity injury, as well as occupants in crashes with higher changes in velocity.
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