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Many rollover safety researches have been conducted experimentally and analytically to investigate the underlying causes of vehicle accidents and develop rollover test procedures and test methodologies to help understand the nature of rollover crash events. In addition, electronic and/or mechanical instrumentation are used in dummy and vehicle to measure their responses that allow both vehicle kinematics study and occupant injury assessment. However, method for measurement of dynamic structural deformation needs further exploration, and means to monitor vehicle-to-ground contact load is still lacking. Thus, this paper presents a method for determining the vehicle-to-ground load during laboratory-based rollover tests using results obtained from a camera-matching photogrammetric technology as inputs to a FE SUV model using a nonlinear crash analysis code.

A survey of accident reports and experimental studies showed that the lap belt does not provide sufficient protection for the pregnant car occupant in whom fetal injury or abortion often resulted. A net-type restraint system was used on pregnant sub-human primates which were subjected to decelerations of over 40g in a forward-facing configuration. The animals survived multiple impacts without treatment and delivered healthy infants. The data presented include belt loads, body kinematics, and intrauterine pressure measurements.

In a frontal automotive crash, the driver's foot is usually stepping on the brake pedal as an instinctive response to avoid a collision. The tensile force generated in the Achilles tendon produces a compressive preload on the tibia. If there is intrusion of the toe board after the crash, an additional external force is applied to the driver's foot. A series of dynamic impact tests using human cadaveric specimens was conducted to investigate the combined effect of muscle preloading and external force. A constant tendon force was applied to the calcaneus while an external impact force was applied to the forefoot by a rigid pendulum. Preloading the tibia significantly increased the tibial axial force and the combination of these forces resulted in five tibial pylon fractures out of sixteen specimens.

This work describes the development of a three-dimensional finite element model of the human ankle/foot complex. This model depicts the primary elements of a 50th percentile human ankle. It includes all the bones of the foot up to the distal tibia/fibula. It also contains the soft tissues of the plantar surface of the foot along with most of the ankle joint ligaments and retinacula. To calibrate the model, a plate with various initial velocities of 5, 7.5 and 10 mph is impacted at the plantar surface of the foot. The model is strictly stabilized by the intrinsic anatomical geometry and the ligamentous structure. It demonstrates to a great extent its capacity to replicate the dynamic response. Global responses of output acceleration and force time histories are obtained and compared reasonably well with experimental data.

The purpose of this paper is to address abdominal injury and response in cadaver whole body side impacts and abdominal injury risk functions in SID and BIOSID in whole body impacts. Side impact sled tests were performed at Wayne State University using cadavers, SID and BIOSID, with response measured at the shoulder, thorax, abdominal and pelvic levels. The data at the abdominal level are presented here. These data provide further understanding of abdominal tolerance and response in lateral impact and the ability of side impact dummies to predict abdominal injury. In addition, the padding data provide insight into tolerable armrest loads.

Thirty-seven SID side impact sled tests were performed using a rigid wall and a padded wall with fourteen different padding configurations. The Thoracic Trauma Index (TTI) and Average Spine Acceleration (ASA) were measured in each test. TTI and ASA were evaluated in terms of their ability to predict injury in identical cadaver tests and in terms of their ability to predict the harm or benefit of padding of different crush strengths. SID ASA predicted the injury seen in WSU-CDC cadaver tests better than SID TTI. SID ASA predicted that padding of greater than 20 psi crush strength is harmful (ASA > 40 g's). SID TTI predicted that padding of greater than 20 psi crush strength is beneficial (TTI < 85 g's). SID TTI predicts the benefit of lower impact velocity. However, SID ASA appears more useful in assessing the harm or benefit of door padding or air bags.

Numerical analyses of head and neck response during side impact are presented in this paper. A mathematical human model for side impact simulation was developed based on previous studies of other researchers. The effects of muscular activities during severe side impact were analyzed with the use of this model. This study shows that the effect of muscular activities is significant especially if the occupant is prepared to resist the impact. This result suggests that the modeling of muscles is important for the simulation of real accident situation.

A finite element model of the human thorax was merged with a rigid body finite element implementation of the Hybrid III dummy (after removal of the Hybrid III thorax) and the combined model is used in simulations of an out of position driver during airbag deployment. Parameters related to injury, such as A-P thorax deformation, Viscous Criterion, rib stress distribution and strain in the thoracic contents are used to quantify the thoracic injury response. Initial driver position is varied to examine the relationship between distance from the airbag module and thoracic injury risk. The potential for injury mitigation through modulation of airbag inflation after initiation is also investigated. The utility of the combined model as an effective tool for the analysis of occupant kinematics and dynamics, examination of injury mechanisms, and optimization of restraint system design parameters is demonstrated.

Accident cases are examined to determine the injury mechanism for foot/ankle moderate and greater injuries in vehicle crashes. The authors examine 480 in-depth cases from the National Accident Sampling System for the years 1979 through 1987. An injury mechanism - a description of how the foot/ankle physically interacted with the interior of the vehicle - is assigned to each of the injured occupants. For the accidents in which the 480 occupants were injured, the more prominent types of vehicle collisions are characterized.

Complete validation of any finite element (FE) model of the human brain is very difficult due to the lack of adequate experimental data. However, more animal brain injury data, especially rat data, obtained under well-defined mechanical loading conditions, are available to advance the understanding of the mechanisms of traumatic brain injury. Unfortunately, internal response of the brain in these experimental studies could not be measured. The aim of this study was to develop a detailed FE model of the rat brain for the prediction of intracranial responses due to different impact scenarios. Model results were used to elucidate possible brain injury mechanisms. An FE model, consisting of more than 250,000 hexahedral elements with a typical element size of 100 to 300 microns, was developed to represent the brain of a rat. The model was first validated locally against peak brain deformation data obtained from nine unique dynamic cortical deformation (vacuum) tests.

Knee injuries represent about 10% of all injuries suffered during car crashes. Efforts to assess the injury risk to the posterior cruciate ligament (PCL) have been based on a study available in the literature (Viano et al., 1978), in which only two of the five knees tested had PCL ruptures. The aims of the current study were to repeat the study with a higher number of samples, study the effects of other soft tissues on knee response, and assess the adequacy of the experimental setup for the identification of a PCL tolerance. A total of 14 knees were tested using a high-speed materials testing machine. Eight were intact knees (with the patella and all the muscular and ligamentous structures), three were PCL-only knees (patella and all the muscular and ligamentous structures other than the PCL removed), and the last three were PCL-only knees with the tibia protected from bending fracture.

Twelve side impact sled tests were performed using a horizontally accelerated sled and a Heidelberg-type seat fixture. The purpose of these tests was to better understand biomechanical response and injury tolerance in whole-body side impacts. In these tests the subject's whole body impacted a sidewall with one of three surface conditions: 1) a flat, rigid side wall, 2) a side wall with a 6″ pelvic offset, or 3) a flat, padded side wall. This paper presents the biomechanical response and injury tolerance data obtained for the pelvis. Peak values of sacral-y acceleration, pelvic force, compression and velocity x compression were evaluated as predictors of pelvic injury. Based on Logist analysis, Vmax x Cmax was the best predictor of probability of pelvic fracture in this test series, while peak pelvic force and peak compression also performed well.

Twelve side impact sled tests were performed using a horizontally accelerated sled and a Heidelberg-type seat fixture. In these tests the subject's whole body impacted a sidewall with one of three surface conditions: 1) a flat, rigid side wall, 2) a side wall with a 6″ pelvic offset, or 3) a flat, padded side wall. This series of runs provided a good test of how injury criteria perform under a variety of impact surface conditions. In this study thoracic injury criteria based on force, acceleration, compression, and velocity x compression (VC) were evaluated. Maximum compression and VCmax proved to be the best injury indicators in this series. Biomechanical response and injury tolerance are also presented.

Relative motion between the brain and skull may explain many types of brain injury such as intracerebral hematomas due to bridging veins rupture [1] and cerebral contusions. However, no experimental methods have been developed to measure the magnitude of this motion. Consequently, relative motion between the brain and skull predicted by analytical tools has never been validated. In this study, radio opaque markers were placed in the skull and neutral density markers were placed in the brain in two vertical columns in the occipitoparietal and temporoparietal regions. A bi-planar, high-speed x-ray system was used to track the motion of these markers. Due to limitations in current technology to record the x-ray image on high-speed video cameras, only low- speed (﹤ 4m/s) impact data were available.

The purpose of this study was to determine the characteristics of eighteen lumbar spine motion segments subjected to lateral shear forces under quasi-static (0.5 mm/s) and dynamic (500 mm/s) test conditions. The quasi-static test was also performed on the lumbar spine of a side impact anthropomorphic test device, the EuroSID-2 (ES-2). In the quasi-static tests, the maximum force before disc-endplate separation in the PMHS lumbar motion segments was 1850 ± 612 N, while the average linear stiffness of PMHS lumbar motion segments was 323 ± 126 N/mm. There was a statistically significant difference between the quasi-static (1850 ± 612 N) and dynamic (2616 ± 1151 N) maximum shear forces. The ES-2 lumbar spine (149 N/mm) was more compliant than the PMHS lumbar segments under the quasi-static test condition.

Computational simulations are conducted for several head impact scenarios using a three dimensional finite element model of the human brain in conjunction with accelerometer data taken from crash test data. Accelerometer data from a 3-2-2-2 nine accelerometer array, located in the test dummy headpart, is processed to extract both rotational and translational velocity components at the headpart center of gravity with respect to inertial coordinates. The resulting generalized six degree-of-freedom description of headpart kinematics includes effects of all head impacts with the interior structure, and is used to characterize the momentum field and inertial loads which would be experienced by soft brain tissue under impact conditions. These kinematic descriptions are then applied to a finite element model of the brain to replicate dynamic loading for actual crash test conditions, and responses pertinent to brain injury are analyzed.

Brain tissue architecture consists of a complex network of neurons and vasculature interspersed within a matrix of supporting cells. The role of the relatively suffer blood vessels on the more compliant brain tissues during rapid loading has not been properly investigated. Two 2-D finite element models of the human head were developed. The basic model (Model I) consisted of the skull, dura matter, cerebral spinal fluid (CSF), tentorium, brain tissue and the parasagittal bridging veins. The pia mater was also included but in a simplified form which does not correspond to the convolutions of the brain. In Model II, major branches of the cerebral arteries were added to Model I. Material properties for the brain tissues and vasculature were taken from those reported in the literature. The model was first validated against intracranial pressure and brain/skull relative motion data from cadaveric tests.

This paper is part of a four year study to systematically define side impact injury in terms of the kinetic response of a suitable anthropomorphic dummy. Last year a paper was presented at the Experimental Safety Vehicle Conference in Germany which analyzed side impact dummy response and injury prediction based on cadaver data generated by the Highway Safety Research Institute. These subjects were generally older than those discussed in the current paper. This paper includes data from a number of University of Heidelberg cadaver sled tests-including padding tests which we recently found to be (1) critical for a definitive analysis and (2) previously not available. Two advanced dummies, whose design specifications are based upon biomechanical data, are currently being evaluated by the biomechanical community. The two dummies are (1) a Side Impact Dummy (SID) designed by the Highway Safety Research Institute (HSRI) and (2) the Association Peugeot-Renault (APR) dummy from France.

Since 1976, the National Highway Traffic Safety Administration (NHTSA) has pursued biomechanical research concerning lateral impacts to automotive occupants. These efforts have included (a) the generation of an experimental data base containing both detailed engineering and physiological responses of human surrogates experiencing lateral impacts, (b) the analysis of this data base to develop both an injury index linking the engineering parameters to an injury severity level and response corridors to guide in the design of a test dummy, and (c) the development and refinement of a side impact test dummy suitable for use in safety systems development and evaluation. The progress of these efforts has been periodically reported in the literature [1-17]* and these references document the evolutionary trail NHTSA has followed over the duration of this research program.

Numerical analyses frequently accompany experimental investigations that study injury biomechanics and improvements in automotive safety. Limited by computational speed, earlier mathematical models tended to simplify the system under study so that a set of differential equations could be written and solved. Advances in computing technology and analysis software have enabled the development of many sophisticated models that have the potential to provide a more comprehensive understanding of human impact response, injury mechanisms, and tolerance. In this article, 50 years of publications on numerical modeling published in the Stapp Car Crash Conference Proceedings and Journal were reviewed. These models were based on: (a) author-developed equations and software, (b) public and commercially available programs to solve rigid body dynamic models (such as MVMA2D, CAL3D or ATB, and MADYMO), and (c) finite element models.