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The pia-arachnoid complex (PAC) covering the brain plays an important role in the mechanical response of the brain due to impact or inertial loading. However, the mechanical properties of the pia-arachnoid complex and its influence on the overall response of the brain have not been well characterized. Consequently, finite element (FE) brain models have tended to oversimplify the response of the pia-arachnoid complex, possibly resulting in a loss of accuracy in the model predictions. The aim of this study was to determine, experimentally, the material properties of the pia-arachnoid complex under quasi-static and dynamic loading conditions. Specimens of the pia-arachnoid complex were obtained from the parietal and temporal regions of freshly slaughtered bovine subjects with the specimen orientation recorded. Single-stroke, uniaxial quasi-static and dynamic tensile experiments were performed at strain-rates of 0.05, 0.5, 5 and 100 s-1 (n = 10 for each strain rate group).

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.

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.

A series of volunteer and dummy impact experiments was performed on a Hyge-type (accelerator) sled to study the relative motion between the upper torso restraint and the torso surface. Kinematic measurements were made using a three-dimensional photogrammetric analysis of high-speed film data. Belt slip was found to be in the range of approximately 10 to 30 mm with more slip experienced by volunteers than the dummy. The dummy showed a slight change in amount of slip with acceleration level and all slip takes place within the first 80 ms of belt loading.

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.

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.

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.

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.

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.

High-speed biplane x-ray and neutral density targets were used to examine brain displacement and deformation during impact. Relative motion, maximum principal strain, maximum shear strain, and intracranial pressure were measured in thirty-five impacts using eight human cadaver head and neck specimens. The effect of a helmet was evaluated. During impact, local brain tissue tends to keep its position and shape with respect to the inertial frame, resulting in relative motion between the brain and skull and deformation of the brain. The local brain motions tend to follow looping patterns. Similar patterns are observed for impact in different planes, with some degree of posterior-anterior and right-left symmetry. Peak coup pressure and pressure rate increase with increasing linear acceleration, but coup pressure pulse duration decreases. Peak average maximum principal strain and maximum shear are on the order of 0.09 for CFC 60 Hz data for these tests.

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.

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.

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.