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A study of the biomechanical factors concerned with the design of side structures and doors for crashworthiness has been made. Questions regarding optimum stiffness, location of reinforcing members, effect of armrests, and padding have been answered within the framework of injury criteria models. Results of animal studies, cadaver studies, and anthropometric dummies have been combined to produce injury criteria for lateral impacts to the head, thorax, and abdomen. Impacts were applied utilizing a specially designed “air gun” in a laboratory environment emphasizing reproducibility and control. Full-scale crash simulations were performed on an impact sled to verify the results of the more specialized tests and analyses. Scaled models of current production doors were used in the animal series. Scaling relationships for various species of animals have been developed and extrapolated to man. Significant differences in right and left side tolerances to impact were noted and detailed.

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.

During certain events such as underbody blasts due to improvised explosive devices, occupants in military vehicles are exposed to inferior-to-superior loading from the pelvis. Injuries to the pelvis-sacrum-lumbar spine complex have been reported from these events. The mechanism of load transmission and potential variables defining the migration of injuries between pelvis and or spinal structures are not defined. This study applied inferior-to-superior impacts to the tuberosities of the ischium of supine-positioned five post mortem human subjects (PMHS) using different acceleration profiles, defined using shape, magnitude and duration parameters. Seventeen tests were conducted. Overlay temporal plots were presented for normalized (impulse momentum approach) forces and accelerations of the sacrum and spine.

Engineering efforts directed at better occupant safety require a thorough understanding of available epidemiologic data. Epidemiologic studies using clinical as well as accident information facilitates the prioritization of biomechanics research so that controlled laboratory experimentation and/or analytical models can be advanced. This information has also value in dictating levels and types of injury that are critical to the development of anthropomorphic test devices used in crash environments. In this paper, motor vehicle accident related (excluding pedestrians, bicyclists, and motorcyclists) epidemiologic data were obtained from clinical and computerized accident (National Accident Sampling System-NASS) files. Clinical data were gathered from patients admitted to the Medical College of Wisconsin Affiliated Hospitals, and fatalities occurring in Milwaukee County, State of Wisconsin. NASS database with specific focus on spinal injuries of motor vehicle occupants was also used.

The purpose of this study was to determine scale factors for small, mid-size and large adults using a caprine model. In a previous study conducted in our lab, scaling relationships were developed to define cervical spine tolerance values of children using caprine specimens. In that study, tolerances were normalized with respect to an average adult. Because airbag-related injuries are associated with out-of-position children and small adult females, additional experimental data are needed to better estimate human tolerance. In the present study, cervical spine radiographs from the 5th, 50th and 95th percentile human adults were used to determine vertebral body heights for small, mid-size and large anthropometries. Mean human vertebral body heights were computed for each anthropometry and were normalized with respect to mid-size anthropometry.

Statistics indicate that during the past decade (1967-1976) the number of general aviation aircraft involved in an accident is equivalent to at least 38% of the total U.S. production during that period. Estimates that an aircraft will be involved in an accident over a 20 year life range are as high as 60-70%. Recognition of this probability has led to crashworthiness and occupant survivability “packaging” design concepts as offering the most realistic approach to reduction of serious and fatal injuries when an accident occurs. This paper reviews and illustrates current general aviation aircraft accident experience relative to occupant impact injury and damage indexes, and provides new data relative to current-generation aircraft.

Although it has been well established that the lap (seat) belt offers considerable protection against injury or death in crash environments, there has long been controversy over the injury potential to the pregnant female. This question is of importance in consideration of restraint and seat protective environments for both aircraft and automotive vehicles. Most of the 4 million pregnant women per year in the United States travel by automobile, with a large number traveling by Commercial Civil Aircraft or the Military Air Transport Service. Thus a sizeable population is involved. This combined study by the Civil Aeromedical Institute, F. A. A., 6571st Aeromedical Research Laboratory, Holloman AFB, and the University of Oklahoma School of Medicine, has been concerned with the clinical, experimental, and applied aspects.

Cervical spine injuries can occur in military scenarios from events such as underbody blast events. Such scenarios impart inferior-to-superior loads to the spine. The objective of this study is to develop human injury risk curves (IRCs) under this loading mode using Post Mortem Human Surrogates (PMHS). Twenty-five PMHS head-neck complexes were obtained, screened for pre-existing trauma, bone densities were determined, pre-tests radiological images were taken, fixed in polymethylmethacrylate at the T2-T3 level, a load cell was attached to the distal end of the preparation, positioned end on custom vertical accelerator device based on the military-seating posture, donned with a combat helmet, and impacted at the base. Posttest images were obtained, and gross dissection was done to confirm injuries to all specimens. Axial and resultant forces at the cervico-thoracic joint was used to develop the IRCs using survival analysis.

The purpose of this study was to investigate the use of the chestband in side impact conditions by conducting validation experiments, and evaluating its feasibility by conducting a series of human cadaver tests under side impact crash scenarios. The chestband validation tests were conducted by wrapping the device around the thorax section of the Side Impact Dummy at its uppermost portion. The anthropomorphic test device was seated on a Teflon pad on a platform to accept impact from the side via a pendulum system. Tests were conducted at 4.5, 5.7, and 6.7 m/sec velocities using round and flat impactors. Retroreflective targets were placed at each strain gauge channel on the edge of the chestband. The test was documented using a high-speed digital video camera operating at 4500 frames/sec. Deformation contours and histories were obtained using the chestband electronic signals in combination with the RBAND-PC software.

The patho-anatomic alterations due to vertical loading of the human cervical column were documented and correlated with biomechanical kinematic data. Seven fresh human cadaveric head-neck complexes were prepared, and six-axis load cells were placed at the proximal and distal ends of the specimens to document the gross biomechanical response. Retroreflective markers were placed on bony landmarks of vertebral bodies, articular facets, and spinous processes along the entire cervical column. Targets were also placed on the occiput and arch of C1. The localized movements of these markers were recorded using a video analyzer during the entire loading cycle. Pre-test two-dimensional, and three-dimensional computerized tomography (CT), and plane radiographs were taken. The specimens were loaded to failure using an electrohydraulic testing device at a rate of 2 mm/s.

Lower cervical spine injuries are more common in survivors of motor vehicle crashes sustaining neck trauma. Injury criteria are determined using upper neck loads in dummies although a lower neck load cell exists. Due to a paucity of lower neck data from post mortem human subject (PMHS) studies, this research was designed to determine the head-neck biomechanics with a focus on lower neck metrics and injuries. Sixteen frontal impact tests were conducted using five belted PMHS. Instrumentation consisted of a pyramid-shaped nine accelerometer package on the head, tri-axial accelerometer on T1, and uniaxial accelerometer on the sled. Three-dimensional kinematics of the head-neck complex were obtained using a 20-camera high-speed motion analysis system. Testing sequence was: low (3.6 m/s), medium (6.9 m/s), repeat low, and high (15.8 m/s) velocities. Trauma evaluations were made between tests. Testing was terminated upon confirmation of injuries.

This study was conducted to collect data and gain insights relative to the mechanisms and factors involved in hip injuries during frontal crashes and to study the tolerance of hip injuries from this type of loading. Unembalmed human cadavers were seated on a standard automotive seat (reinforced) and subjected to knee impact test to each lower extremity. Varying combinations of flexion and adduction/abduction were used for initial alignment conditions and pre-positioning. Accelerometers were fixed to the iliac wings and twelfth thoracic vertebral spinous process. A 23.4-kg padded pendulum impacted the knee at velocities ranging from 4.3 to 7.6 m/s. The impacting direction was along the anteroposterior axis, i.e., the global X-axis, in the body-fixed coordinate system. A load cell on the front of the pendulum recorded the impact force. Peak impact forces ranged from 2,450 to 10,950 N. The rate of loading ranged from 123 to 7,664 N/msec. The impulse values ranged from 12.4 to 31.9 Nsec.

The American population is getting heavier and automated vehicles will accommodate unconventional postures. While studies replicating mid-size and upright fore-aft seated occupants are numerous, experiments with post-mortem human subjects (PMHS) with obese and reclined occupants are sparse. The objective of this study was to compare the kinematics of the head-neck, torso and pelvis, and document injuries and injury patterns in frontal impacts. Six PMHS with a mean body mass index of 38.2 ± 5.3 kg/m2 were equally divided between upright and reclined groups (seatback: 23°, 45°), restrained by a three-point integrated belt, positioned on a semi-rigid seat, and exposed to low and moderate velocities (15, 32 km/h). Data included belt loads, spinal accelerations, kinematics, and injuries from x-rays, computed tomography, and necropsy. At 15 km/h speed, no significant difference in the occupant kinematics and evidence of orthopedic failure was observed.

The objective of the study was to determine the thorax and abdomen deflection-time corridors in oblique side impacts. Data were analyzed from Post Mortem Human Surrogate (PMHS) sled tests, certain aspects of which were previously published. A modular and scalable anthropometry-specific segmented load-wall system was fixed to the platform of the sled. Region-specific forces were recorded from load cells attached to the load-wall plates. The thorax and abdomen regions were instrumented with chestbands, and deflection contours were obtained. Biomechanical responses were processed using the impulse-momentum normalization method and scaled to the mid-size male mass, 76-kg. The individual effective masses of the thorax and abdomen were used to determine the scale factors in each sled test, thus using the response from each experiment. The maximum deflections and their times of attainments were obtained, and mean and plus minus one standard deviation corridors were derived.

While numerous studies have been conducted to determine side impact responses of Post Mortem Human Surrogates (PMHS) using sled and other equipment, experiments using the biological surrogate in modern full-scale vehicles are not available. The present study investigated the presence of oblique loading in moving deformable barrier and pole tests. Three-point belt restrained PMHS were positioned in the left front and left rear seats in the former and left front seat in the latter condition and tested according to consumer testing protocols. Three chestbands were used in each specimen (upper, middle and lower thorax). Accelerometers were secured to the skull, shoulder, upper, middle and lower thoracic vertebrae, sternum, and sacrum. Chestband signals were processed to determine magnitudes and angulations of peak deflections. The magnitude and timing of various signal peaks are given. Vehicle accelerations, door velocities, and seat belt loads are also given.

Human impact injury and survival tolerance levels for various crash conditions are presented on the basis of currently available biomedical and biomechanical knowledge. Consideration of physical factors influencing trauma-including body orientation, restraint system, magnitude, distribution, and time duration of deceleration-are summarized, as well as tabulations and sources of data for both whole body and regional impact tolerances. These biological data concerning human impact tolerances are provided as guidelines for improved engineering design of general aviation crashworthiness.

The objective of this study was to determine region-specific deflection responses of the WorldSID and ES2-re devices under pure lateral and oblique side impact loading. A modular, anthropometry-specific load wall was used. It consisted of the Shoulder, Thorax, Abdomen, superior Pelvis, and inferior Pelvis plates, termed the STAPP load wall design. The two devices were positioned upright on the platform of a bench seat, and sled tests were conducted at 3.4, 6.7, and 7.5 m/s. Two chestbands were used on each dummy at the thoracic and abdominal regions. Internal sensors were also used. Effective peak deflections were obtained from the chestband contours. Based on the preselected lateral-most point/location on the pretest contour, “internal sensor-type” peak deflections were also obtained using chestband contours. In addition, peak deflection data were obtained from internal sensor records.

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.

The objective of the present exploratory study is to understand occupant responses in oblique and side-facing seats in the aviation environment, which are increasingly installed in modern aircrafts. Sled tests were conducted using intact Post Mortem Human Surrogates (PMHS) seated in custom seats approximating standard aircraft geometry. End conditions were selected to represent candidate aviation seat and restraint configurations. Three-dimensional head center-of-gravity linear accelerations, head angular velocities, and linear accelerations of the T1, T6, and T12 spinous processes, and sacrum were obtained. Three-dimensional kinematics relative to the seat were obtained from retroreflective targets attached to the head, T1, T6, T12, and sacrum. All specimens sustained spinal injuries, although variations existed by vertebral level.

A study of free-fall accidents and resulting injuries was conducted to determine how useful these types of data could be in establishing human injury tolerance limits. “Tolerance” was examined primarily for children at two levels - reversible injury and threat to survival. The specific objectives were to investigate specific free-falls in sufficient depth to permit biomedical or mathematical reconstruction of the fall, simulate selected free-falls to estimate impact response, and compare predicted responses with observed injuries as a means of estimating human tolerance levels. From more than 2100 reported free-falls, 110 were investigated on-site. Seven head-first and three feet-first falls were then simulated using the MVMA 2-D Crash Victim Simulator. Newspaper reports of free-falls showed that males fell six times as often as females and most often while at work. Children fell from windows and balconies more often than from any other hazard.