Search Results

Biomechanical data on the response of the face to localized and distributed loads are analyzed to provide performance goals for a biomechanically realistic face. Previously proposed facial injury assessment techniques and dummy modifications are reviewed with emphasis on their biomechanical realism. A modification to the Hybrid III dummy, called the GM Hybrid III Deformable Face, is described. The modification produces biomechanically realistic frontal impact response for both localized and distributed facial loads and provides for contact force determination using conventional Hybrid III instrumentation. The modification retains the anthropometric and inertial properties and the forehead impact response of the standard Hybrid III head.

A versatile high-speed cineradiographic system developed in the Biomechanics Department of The University of Michigan's Highway Safety Research Institute has recently been completed, for application to human injury and tolerance and occupant protection research. This system consists of a high-speed motion picture camera which views a 2-inch diameter output phosphor of a high gain 4-stage, magnetically focussed image intensifier tube, gated on and off synchronously with shutter pulses from the motion picture camera. A fast lens optically couples the input photocathode of the image intensifier tube to x-ray images produced on a fluorescent screen by a d-c x-ray generator.

This paper presents the rationale behind the development of a shoulder belt load cell suitable for application in racings cars. The design of the load cell and the operational parameters necessary for a research-quality measurement device for biomechanics research in racing car crashes and the performance of the device in sled tests are described.

The purpose of this literature review was to determine areas of automotive injury information that may add to knowledge of injury type, frequency, severity, and cause. This paper is a review of the literature concentrating on the period between 1965 and present. Literature on car, van, or 1ight truck occupants has been reviewed for injury frequencies, types, and locations. Current experimental biomechanical articles are also included. A search was made for descriptions of injury frequency, restraint effectiveness, and the causes of specific injuries. Medical and engineering journals, texts, and books were reviewed. For convenience, this report is divided into sections by body region with an overview introduction on the anatomy of the specific region.

The purpose of this study was to investigate approaches evaluating the performance of safety systems in crash tests and by analytical simulations. The study was motivated by the need to consider the adequacy of injury criteria and tolerance levels in FMVSS 208 measuring safety performance of restraint systems and supplements. The study also focused on additional biomechanical criteria and performance measures which may augment FMVSS 208 criteria and alternative ways to evaluate dummy responses rather than by comparison to a tolerance level. Additional analysis was conducted of dummy responses from barrier crash and sled tests to gain further information on the performance of restraint systems. The analysis resulted in a new computer program which determined several motion and velocity criteria from measurements made in crash tests.

The purpose of this study is to provide an understanding of driver kinematics, injury mechanisms and spinal loads causing thoracolumbar spinal fractures in Indianapolis-type racing car drivers. Crash reports from 1996 to 2006, showed a total of forty spine fracture incidents with the thoracolumbar region being the most frequently injured (n=15). Seven of the thoracolumbar fracture cases occurred in the frontal direction and were a higher injury severity as compared to rear impact cases. The present study focuses on thoracolumbar spine fractures in Indianapolis-type racing car drivers during frontal impacts and was performed using driver medical records, crash reports, video, still photographic images, chassis accelerations from on-board data recorders and the analysis tool MADYMO to simulate crashes. A 50th percentile, male, Hybrid III dummy model was used to represent the driver.

This paper contains a review of current information on biological structure, material properties and failure characteristics of bone, articular cartilage, ligament and tendon. The load-deformation response of biological tissues is presented with particular reference to the microstructure of the material. Although many of the tissues have been characterized as linear, elastic and isotropic materials, they actually have a more complicated response to load, which includes stiffening with increasing strain, inelastic yield, and strain rate sensitivity. Failure of compact and cancellous bone depends on the rate, type, and direction of loading. Soft biological tissues are vlscoelastie and exhibit a higher load tolerance with an increasing rate of loading. The paper includes a discussion on the basic principles of biomechanics and emphasizes material properties and failure characteristics of biological tissues subjected to impact loading.

Life threatening chest injury can involve partial or full tears of the aorta. Investigations of fatal injuries in automobile accidents indicate that aortic trauma occurs in 10-20% of the cases. The major sites of aortic trauma include the aortic isthmus, the root, and the aortic insertion at the diaphragm - all of which are points of aortic tethering. The biomechanics of the injury process involve stretching of the vessel from points of tethering and hydrodynamic increases in blood pressure, which stretch the tissue to failure at a strain of about 150%. The non-isotropic stretch response of aortic tissue is discussed with reference to the frequent transverse orientation of the laceration. Congenital and pathophysiological conditions also influence the failure characteristics of the tissue. The significant factors associated with traumatic injury of the aorta are discussed in this review paper which is based on published technical information.

This paper discusses the development of adequate criteria and evaluation methods for seat belt restraint design. These criteria should include the effect of seat belts in abdominal injury as well as head injury. It is concluded that belt load limiters and energy-absorbing devices should limit head-to-vehicle contact, ensure that the lap belt maintains proper contact with the bony pelvic girdle, and limit the belt loads. Studies are made of pulse shape and belt fabrics. Currently available mathematical models are used for the studies included in the paper.

Knee bolsters on the lower instrument panel have been designed to control occupant kinematics during sudden deceleration. However, a wide variability in car occupant anthropometry and choice of seating posture indicates that lower-extremity contacts with the impingement bolster could predominantly load the flexed leg through the knee (acting through the femur) or through the tibia (acting through the knee joint). Potential injuries associated with these types of primary loading may vary significantly and an understanding of potential trauma mechanisms is important for proper occupant restraint.

Thoracic impact response and injuries of living and postmortem porcine siblings were investigated to quantify comparative differences. Thirteen male animals, averaging 61.4 kg, from five different porcine litters comprised the two animal samples. Porcine brothers were subjected to similar impact exposures for which at least one brother was tested live, anesthetized and another dead, post rigor with vascular repressurization. Statistically significant differences in biomechanical responses and injuries were observed between live and postmortem siblings. On the average the anesthetized live animals demonstrated a greater thoracic compliance, as measured by increased normalized total deflections (21% Hi), and reduced overall injuries (AIS 14% Lo and rib fractures 26% Lo) at lower peak force levels (13% Lo) than did the postmortem subjects. However, individual comparisons of “match-tested” siblings demonstrated very similar responses in some cases.

A femur fracture injury criterion is presented that assesses the dependence of the permissible human knee load on the duration of the primary force exposure. Currently a constant allowable femur load limit of 7.6 kN (1700 lb) is specified in FMVSS 208, but recently the Federal Government proposed elevating the allowable limit to 10.0 kN (2250 lb), which is in excess of the limited experimental average static femur fracture force of 8.90 kN (2000 lb). A general analysis of all of the available biomechanics data and mathematical models on femoral impact response and fracture indicates a significant load time dependence for primary pulse durations below 20 ms that can elevate the permissible femur load above the Federally proposed allowable limit of 10.0 kN (2250 lb).

The crash recorder is an important data gathering device in motorsports. Since the introduction of crash recording in Indy Cars in 1993, the data gathered has been critical in developing improvements in race car structures and driver protection systems. This report will examine which sanctioning bodies use recorders, what type of data is gathered, and how that data is used to improve driver's safety in racing.

The close-fitting cockpit of the modern Indy car single seat race car has the potential to provide a high level of head and neck impact protection in rear and side impacts. Crash investigation has shown that a wide variety of materials have been used as the padding for these cockpits and, as a result, produced varying outcomes in crashes. Additionally, these pads have not always been positioned for optimal performance. The purpose of this study was to investigate the head impact performance of a variety of energy-absorbing padding materials under impact conditions typical of Indy car rear impacts and to identify superior materials and methods of improving their performance as race car head pads. An extensive series of tests with the helmeted Hybrid III test dummy head and neck on an impact mini-sled was conducted to explore head padding concepts.

Airbags and safety belts are now viewed as complements for occupant protection in a crash. There is also a view that no single solution exists to ensure safety and that a system of protective technologies is needed to maximize safety in the wide variety of real automotive crashes. This paper compares the fatality prevention effectiveness, and biomechanical principles of occupant restraint systems. It focuses on the effectiveness of various systems in preventing fatal injury assuming the restraint is available and used. While lap-shoulder belts provide the greatest safety, airbags protect both belted and unbelted occupants.

This paper covers the development of the General Motors Energy Absorbing Steering System beginning with the work of the early crash injury pioneers Hugh DeHaven and Colonel John P. Stapp through developments and introduction of the General Motors energy absorbing steering system in 1966. evaluations of crash performance of the system, and further improvement in protective function of the steering assembly. The contributions of GM Research Laboratories are highlighted, including its safety research program. Safety Car, Invertube, the biomechanic projects at Wayne State University, and the thoracic and abdominal tolerance studies that lead to the development of the Viscous Injury Criterion and self-aligning steering wheel.

Objective: This study analyzes rear sled tests with a 95th% male and 5th% female Hybrid III dummy in various seating positions on ABTS (All Belt to Seat) seats in severe rear impact tests. Dummy interactions with the deforming seatback and upper body extension around the seat frame are considered. Methods: The 1st series involved an open sled fixture with a Sebring ABTS seat at 30 mph rear delta V. A 95th% Hybrid III dummy was placed in four different seating positions: 1) normal, 2) leaning inboard, 3) leaning forward and inboard, and 4) leaning forward and outboard. The 2nd series used a 5th% female Hybrid III dummy in a Grand Voyager body buck at 25 mph rear delta V. The dummy was leaned forward and inboard on a LeSabre ABTS or Voyager seat. The 3rd series used a 5th% female Hybrid III dummy in an Explorer body buck at 26 mph rear delta V. The dummy was leaned forward and inboard on a Sebring ABTS or Explorer seat.

The purpose of this paper is to establish injury assessment reference values specific to the CRABI 6-Month infant dummy for use in evaluating the interaction of rear-facing infant restraints with a deploying passenger airbag. The available literature on the biomechanics of child injury and mechanical response and the results of impact tests with various child and infant dummies are reviewed and summarized. Estimations of the injury assessment reference values for use with the CRABI 6-Month dummy are made using scaling techniques based on the principles of dimensional analysis and dummy test data from infant restraint tests under conditions where injuries are not likely to occur. The information developed in this report will allow the assessment of injury potential in tests of the interaction of passenger airbags with rear-facing infant restraints. This issue is of particular importance to vehicles with only front seats, such as pickup trucks and sport vehicles.

Biomechanical surrogates are used in various forms to study head impact response in automotive applications and for assessing helmet performance. Surrogate headforms include those from the National Operating Committee on Standards for Athletic Equipment (NOCSAE) and the many variants of the Hybrid III. However, the response of these surrogates to loading at the chin and how that response may affect the loads transferred from the jaw to the rest of the head are unknown. To address part of that question, the current study compares the chin impact response performance of select human surrogates to that of the cadaver. A selection of Hybrid III and NOCSAE based surrogates with fixed and articulating jaws were tested under drop mass impact conditions that were used to describe post mortem human subject (PMHS) response to impacts at the chin (Craig et al., 2008). Results were compared to the PMHS response with cumulative variance technique (Rhule et al., 2002).