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Injury to the far side occupant has been demonstrated as a significant portion of the total trauma in side impacts. The objective of the study was to determine the response of PMHS in far side impact configurations, with and without generic countermeasures, and compare responses to the WorldSID and THOR dummies. A far side impact buck was designed for a sled test system that included a center console and three-point belt system. The buck allowed for additional options of generic countermeasures including shoulder or thorax plates or an inboard shoulder belt. The entire buck could be mounted on the sled in either a 90-degree (3-o'clock PDOF) or a 60-degree (2-o'clock PDOF) orientation. A total of 18 tests on six PMHS were done to characterize the far side impact environment at both low (11 km/h) and high (30 km/h) velocities. WorldSID and THOR-NT tests were completed in the same configurations to conduct matched-pair comparisons.

The objective of the study was to document the thoracic deformation contours in a simulated frontal impact. Unembalmed human cadavers and the Hybrid III anthropomorphic manikins were tested. Data from the newly developed External Peripheral Instrument for Deformation Measurement (EPIDM) was used to derive deformation patterns at upper and lower thoracic levels. Deceleration sled tests were conducted on three-point belt restrained surrogates positioned in the driver's seat (no steering assembly) using a horizontal impact test sled at velocities of approximately 14.0 m/s. Lap and shoulder belt forces were recorded with seat belt transducers. The experimental protocol included a Hybrid III manikin experiment followed by the human cadaver test. Both surrogates were studied under similar input and instrumentation conditions, and identical data acquisition and analysis procedures were used. All six testedcadavers demonstrated multiple bilateral rib fractures.

There is an increasing need to accurately define the soft tissue components of the human cervical spine in order to develop and exercise mathematical analogs such as the finite element model. Currently, a paucity of data exists in the literature and researchers have constantly underscored the need to obtain accurate data on cervical spine ligaments. Consequently, the objective of the study was to determine the geometrical and biomechanical properties of these ligaments from the axis to the first thoracic level. A total of thirty-three human cadavers were used in the study. Geometrical data included the length and cross-sectional area measurements; and the biomechanical properties included the force, deflection, stiffness, energy, stress, strain, and Young's modulus of elasticity data. Data were obtained for the following ligaments: anterior and posterior longitudinal ligaments, joint capsules, ligamentum flavum, and interspinous ligament.

With the widespread use of supplemental restraint systems (airbags), occasional rare injuries have occurred because of the force associated with these systems upon deployment. Recent case studies have demonstrated forearm fractures associated with airbag deployment. The present study was conducted to determine the tolerance of the human forearm under a dynamic bending mode. A total of 30 human cadaver forearm specimens were tested using three-point bending protocol to failure at 3.3 m/s and 7.6 m/s velocities. Results indicated significantly (p < 0.01) greater biomechanical parameters associated with males compared to females. The bending tolerance of the human forearm, however, was found to be most highly correlated to bone mineral density, bone area, and forearm mass. Thus, any occupant with lower bone mineral density and lower forearm geometry/mass is at higher risk. The mean failure bending moment for all specimens was 94 Nm.

This study presents a detailed comparison of internally and externally measured chest deflections resulting from eight tests conducted on three male post mortem human subjects. A hydraulically driven shoulder belt loaded the anterior thorax under a fixed spine condition while displacement data were obtained via a high-speed 16-camera motion capture system (VICON MX™). Comparison of belt displacement and sternal displacement measured at the bone surface provided a method for quantifying effective change in superficial soft tissue depth at the mid sternum under belt loading. The relationship between the external displacement and the decrease in the effective superficial tissue depth was found to be monotonic and nonlinear. At 65 mm of mid-sternal posterior displacement measured externally, the effective thickness of the superficial tissues and air gap between the belt and the skin had decreased by 14 mm relative to the unloaded state.

A finite element human model has been developed to simulate occupant behavior and to estimate injuries in real-world car crashes. The model represents an average adult male of the US population in a driving posture. Physical geometry, mechanical characteristics and joint structures were replicated as precise as possible. The total number of nodes and materials is around 67,000 and 1,000 respectively. Each part of the model was not only validated against human test data in the literature but also for realistic loading conditions. Additional tests were newly conducted to reproduce realistic loading to human subjects. A data set obtained in human volunteer tests was used for validating the neck part. The head-neck kinematics and responses in low-speed rear impacts were compared between the measured and calculated results. The validity of the lower extremity part was examined by comparing the tibia force in a foot impact between the test data and simulation results.

This paper presents a technique for developing corridors from individual subject responses contained in experimental biomechanical data sets. Force-deflection response is used as an illustrative example. The technique begins with a method for averaging human subject force-deflection responses in which curve shape characteristics are maintained and discontinuities are avoided. Individual responses sharing a common characteristic shape are averaged based upon normalized deflection values. The normalized average response is then scaled to represent the given data set using the mean peak deflection value associated with the set of experimental data. Finally, a procedure for developing a corridor around the scaled normalized average response is presented using standard deviation calculations for both force and deflection.

This paper discusses struck-side occupant thoracic response to side-impact loading and the requirements of a sled system capable of reproducing the relevant motions of a laterally impacted vehicle. A simplified viscoelastic representation of a thorax is used to evaluate the effect of the door velocity-time profile on injury criteria and on the internal stress state of the thorax. Simulations using a prescribed door velocity-time profile (punch impact) are contrasted against simulations using a constant-velocity impact (Heidelberg-type impact). It is found that the stress distribution and magnitude within the thorax, in addition to the maximum thorax compression and viscous response, depend not only on the door-occupant closing velocity, but also on the shape of the door velocity-time profile throughout the time of contact with the occupant. A sled system capable of properly reproducing side-impact door and seat motion is described.

This paper presents an analysis of the displacement measurement of the Hybrid III 50th percentile male dummy chest in quasistatic and dynamic loading environments. In this dummy, the sternal chest deformation is typically characterized using a sliding chest potentiometer, originally designed to measure inward deflection in the central axis of the dummy chest. Loading environments that include other modes of deformation, such as lateral translations or rotations, can create a displacement vector that is not aligned with this sensitive axis. To demonstrate this, the dummy chest was loaded quasistatically and dynamically in a series of tests. A string potentiometer array, with the capability to monitor additional deflection modes, was used to supplement the measurement of the chest slider.

The objective of the present study was to determine the kinematics of the human head-neck complex with specific reference to posterior facet joints as a function of rear impact acceleration. Six intact human head-neck complexes were prepared by fixing the first thoracic vertebra in polymethylmethacrylate. The specimens were oriented such that the Frankfurt plane was horizontal and the cervico-thoracic disc was at an angle of 25 degrees to simulate the normal driving position. Retroreflective targets were inserted to the cervical vertebrae. The specimens were subjected to simulated rear impact accelerations using a minisled apparatus. A series of tests were conducted with velocities of 2.1, 4.6, 6.6, 9.3, and 12.4 km/h. In this study, to achieve the objective, results are presented on the facet joint motions at the C4–5, C5–6, and C6–7 levels as a function of change in velocity.

This paper presents a computational study of the effects of three parameters on the resulting thoracic injury criteria in side impacts. The parameters evaluated are a) door velocity-time (V-t) profile, b) door interior padding modulus, and c) initial door-to-occupant offset. Regardless of pad modulus, initial offset, or the criterion used to assess injury, higher peak door velocity is shown to correspond with more severe injury. Injury outcome is not, however, found to be sensitive to the door velocity at the time of first occupant contact. A larger initial offset generally is found to result in lower injury, even when the larger offset results in a higher door velocity at occupant contact, because the increased offset results in contact later in the door V-t profile - closer to the point at which the door velocity begins to decrease. Cases of contradictory injury criteria trends are identified, particularly in response to changes in the pad modulus.

Inertial loading of the head-neck complex occurs in rear impacts wherein the head and neck of the occupant are initially subjected to rearward forces. Epidemiological evidence exists to demonstrate the significance and societal impact of these injuries [4]. From a clinical perspective, trauma secondary to inertial loads belongs to the lower end of the Abbreviated Injury Scale, and no specific diagnostic techniques are available to quantitatively document the injury. Furthermore, identification of the mechanisms of injury and derivation of injury thresholds are limited. In fact, there is a paucity of literature focusing on the reproduction of rear impact-induced neck injuries due to a single-event rear impact. Because the impact acceleration is transmitted to the head from the torso via the cervical column, the components of the human neck play a role in the mechanics of trauma.

Spinal trauma produced from motor vehicle accidents, diving accidents, or falls occur at high rates of loading. This study was undertaken to reproduce clinically relevant cervical spine injuries under controlled conditions. Six isolated head - T2 human cadaveric preparations were tested using an electrohydraulic piston actuator at loading rates from 295 to 813 cm/sec. The Hybrid III head-neck was tested similarly at rates from 401 to 683 cm/sec. The input forces for specimen tests were of higher magnitude and shorter duration than the distally measured forces. In contrast, the Hybrid III head-neck revealed similar magnitude and duration force traces from input to output. The specimen preparations were analyzed kinematically at 1200 frames/sec with 20 to 30 retroreflective targets fixed to each level of the cervical spine. With this technique it is possible to temporally follow cervical damage as a function of applied force.

The objective of the present study was to determine the biomechanics of the human thorax in a simulated frontal impact. Fourteen unembalmed human cadavers were subjected to deceleration sled tests at velocities of nine or 13 m/s. Air bag - knee bolster, air bag - lap belt, and air bag - three-point belt restraint systems were used with the specimen positioned in the driver's seat. Two chest bands were used to derive the deformation patterns at the upper and lower thoracic levels. Lap and shoulder belt forces were recorded with seatbelt transducers. After the test, specimens were evaluated using palpation, radiography, and a detailed autopsy. Thoracic trauma was graded according to the Abbreviated Injury Scale based on autopsy findings. Peak thoracic deformations were normalized with respect to the initial chest depth to facilitate comparison between the specimens.

This paper compares restrained Hybrid III and THOR thoracic kinematics and cadaver injury outcome in 30° oblique frontal and in full frontal sled tests. Peak shoulder belt tension, the primary source of chest loading, changed by less than four percent and peak chest resultant acceleration changed by less than 10% over the 30° range tested. Thoracic kinematics were likewise insensitive to the direction of the collision vector, though they were markedly different between the two dummies. Mid-sternal Hybrid III chest deflection, measured by the standard sternal potentiometer and by supplemental internal string potentiometers, was slightly lower (∼10%) in the oblique tests, but the oblique tests produced a negligible increase in lateral movement of the sternum. In an attempt to understand the biofidelity of these dummy responses, a series of 30-km/h human cadaver tests having several collision vectors (0°, 15°, 30°, 45°) was analyzed.

The objective of the study was to investigate the biomechanical response of the intact cranium. Unembalmed human cadavers were used in the study. The specimens were transected at the base of the skull leaving the intracranial contents intact; x-ray and computed tomography (CT) scans were obtained. They were fixed in a specially designed frame at the auditory meatus level and placed on the platform of an electrohydraulic testing device via a six-axis load cell. Following radiography, quasistatic loading to failure was applied to one of the following sites: frontal, vertex, parietal, temporal, or occipital. Retroreflective targets were placed in two mutually orthogonal planes to record the localized temporal kinematics. Applied load and piston displacement, and the output generalized force (and moment) histories were recorded using a modular digital data acquisition system. After the test, x-ray and CT images were obtained, and defleshing was done.

Head injury is a serious threat to lives of people working around farm machinery. The consequence of head injuries are costly, paralytic, and often fatal. Clinical and biomechanical data on head injuries are reviewed and their application in the analysis of head injury risk associated with farm tractor discussed. A significant proportion of tractor-related injuries and deaths to adults, as well as children, is due directly or indirectly to head injury. An improved injury reporting program and biomechanical studies of human response to tractor rollover, runover, and falls, are needed to understand mechanisms of the associated head injury.

Sixty-three simulated frontal impacts using cadaveric specimens were performed to examine and quantify the performance of various contemporary automotive restraint systems. Test specimens were instrumented with accelerometers and chest bands to characterize their mechanical responses during the impact. The resulting thoracic injury severity was determined using detailed autopsy and was classified using the Abbreviated Injury Scale. The ability of various mechanical parameters and combinations of parameters to assess the observed injury severities was examined and resulted in the observation that belt restraint systems generally had higher injury rates than air bag restraint systems for the same level of mechanical responses. To provide better injury evaluations from observed mechanical parameters without prior knowledge of what restraint system was being used, a dichotomous process was developed.

This paper presents the experimental dynamic tolerance and the force-deformation response corridor of the human cervical spine under compression loading. Twenty human cadaver head-neck complexes were tested using a crown impact to the head at speeds from 2.5 m/s to 8 m/s. The cervical spine was evaluated for pre-alignment by using the concept of the stiffest axis. Mid cervical column (C3 to C5) vertebral body wedge, burst, and vertical fractures were produced in compression. Posterior ligament tears in the lower column occurred under flexion. Anterior longitudinal ligament tears and spinous process fractures occurred under extension. Mean values were: force at failure, 3326 N; deformation at failure, 18 mm; stiffness, 555 N/mm. The deformation at failure parameter was associated with the least variance and should describe the most accurate tolerance measure for the population as a whole.

Axial loading of the calcaneus-talus-tibia complex is an important injury mechanism for moderate and severe vehicular foot-ankle trauma. To develop a more definitive and quantitative relationship between biomechanical parameters such as specimen age, axial force, and injury, dynamic axial impact tests to isolated lower legs were conducted at the Medical College of Wisconsin (MCW). Twenty-six intact adult lower legs excised from unembalmed human cadavers were tested under dynamic loading using a mini-sled pendulum device. The specimens were prepared, pretest radiographs were taken, and input impact and output forces together with the pathology were obtained using load cell data. Input impact forces always exceeded the forces recorded at the distal end of the preparation. The fracture forces ranged from 4.3 to 11.4 kN.