Search Results

The development of the Translations Energy Criteria (TEC) has been underway for the last fifteen years. This criteria addresses brain contusion and skull fracture in the Anterior-Posterior (A-P), Left-Right (L-R), and Superior-Inferior (S-I) directions. The object of this strudy was to evaluate the ability of the TEC to predict non-fracture type injuries to the brain in the L-R and A-P directions up to the level of “serious.” Six unembalmed human cadavers were subjected to one head impact each. Tests one through three were frontal impacts, performed at 1.6, 3.9 and 6.7 m/s respectively. Tests four through six were lateral impacts, performed at 1.9, 3.8 and 6.1 m/s respectively. The impactor weighed 9.05 kg and was fitted with either a rigid or padded surface. The brain was repressurized and the head instrumented with two tri-axial linear accelerometer arrays and one angular velocity transducer. Two high speed motion picture views (1000 frames per second) were taken for each test.

In the last twelve years, the overwhelming effectiveness of restraining children in the United States, Canada and Europe has been proven in reducing death and injury in automobile accidents. Despite the proven benefits of restraining children, one type of injury has not been prevented. This paper is an analysis of stretch injuries to the spinal cord in the upper thoracic or cervical spine. This paper discusses, in general, spinal cord injuries from a biomechanical point of view. The relationship between various loading conditions and the resulting types of spinal cord injuries is discussed. This paper also examines seven real world automobile accidents. Information for each case includes: vehicles involved, type of roadway, crash Delta-V, occupant direction of motion, restraint type, injuries to occupants, and anthropometry of child with spinal cord injury. A description and location of each spinal cord injury that occurred at the time of the accident is discussed.

As an aid to designing an abdominal insert for anthropomorphic dummies, a study of abdominal trauma factors has been made. Questions regarding human impact response and tolerance were answered within the framework of primate scaling. Results of subhuman primate impacts and primate anthropometry were combined to produce injury criteria for frontal and lateral abdominal impacts. Impact response for the frontal and lateral directions was also defined for humans. The primate impact data used in the study was obtained in the early 1970's in laboratory tests utilizing a specially designed “air gun”. This test set up emphasizes reproducibility and control. Human lateral abdominal impact data first published by Walfisch et al., in 1980 were reanalyzed and used to check the primate scaling. Significant differences in impact injury tolerances for various abdominal locations were noted and detailed.

Detailed investigations of automobile crashes in which children under 10 years old were passengers were carried out. The purpose of this study was to investigate the injury patterns of restrained and unrestrained children and to assess the performance of child restraint systems in real world crashes. Crashes which occurred mainly in Washtenaw and Oakland counties of the state of Michigan were surveyed. A total of 348 vehicle crashes involving 494 children less than 10 years old were identified. Forty eight crashes involving 63 children were selected for in-depth investigation. 37% of the children in the investigated cases were restrained by an adult lap belt or a child restraint. It was found that only 4.7% of the children in the overall sample were restrained. Both adult seat belts and child restraints (when used) were found to be effective in reducing injuries in crashes. Head and facial injuries were found to be the most common form of injury to children.

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 is a brief review of the complex subject of human injury mechanisms and impact tolerance. Automotive accident-related injury patterns are briefly described and the status of knowledge in the biomechanics of trauma of the head, neck, chest, abdomen and extremities is discussed.

This paper presents the results of direct impact tests and driving point impedance tests on the legs of seated unembalmed human cadavers. Variables studied in the program included impactor energy and impact direction (axial and oblique). Multiple strain gage rosettes were applied to the bone to determine the strain distribution in the bone. The test results indicate that the unembalmed skeletal system of the lower extremities is capable of carrying significantly greater loads than those determined in tests with embalmed subjects (the only similar data reported in the present literature). The strain analysis indicated that significant bending moments are generated in the femur with axial knee impact. The results of the impedance tests are used to characterize the load transmission behavior of the knee-femur-pelvis complex, and the impact test results are combined with this information to produce suggested response characteristics for dummy simulation of knee impact response.

A three-part program was undertaken to establish an appropriate means of evaluating child restraints in automobile crashes. A standard seat was designed to provide a reproducible test base on which to evaluate child restraint systems in dynamic testing. Developmental and evaluation data are presented, including child restraint performance tests. Results showed the standard seat to be a durable, repeatable, and economical test platform which provides a realistic base for evaluation of child restraint systems. Commercially available three- and six-year-old child dummies were evaluated for their anthropometric measurements and dynamic response characteristics in pendulum impact tests and simulated crashes in representative automobile-child seat restraint environments. Simulated crashes included 20 and 30 mph frontal and 20 mph side impacts on automobile and specially designed bench seats. Two types of child seats, the G. M.

The objective of this study is to investigate the protection potential offered by various production and prototype child restraint systems. In order to achieve this, it is necessary to determine which parameters of child seat performance are relevant to injury prevention. A detailed discussion of these parameters is given in the text. The dynamic performance of 10 child auto-car seats, two harnesses and three infant restraint systems are discussed. The head excursion, head and chest accelerations and overall system performance are presented.

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.