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A parameter study is performed involving several analytical vehicle occupant models in current use, with investigation of neck representations a primary goal. Side, oblique, and rear impact situations are investigated. Attention is given to the effects of varying head-neck mass and moments of inertia, anthropometry, muscle strength, and location, as well as well as strength, of motion-limiting “stops.” A model that replaces the conventional simple ball-joint neck with a two-joint, extensible neck is studied. This model also makes use of joint-stop ellipses to approximate the anatomical range for relatively free angular motion at a joint. Allowance is made for the effect of muscle contraction on occupant dynamics as a function of the degree of voluntary or involuntary tightening of the muscles, based upon experimental findings. A discrete parameter neck model that treats the cervical spine as a linkage of rigid vertebrae and massless, deformable discs is discussed briefly.

During recent years, the Highway Safety Research Institute (HSRI) has developed and validated two- and three-dimensional models describing the motions and forces acting upon an occupant during a collision. These inexpensive-to-operate models are performing with approximately 90% accuracy in parametric studies of classical crash configurations. In our own validation procedures, contacts with automobile development and design groups, and discussions with federal agencies, certain shortcomings of mathematical modeling procedures have been isolated. These include primarily the inability of the user to determine and input data to the computer programs and also to specify force, motion, velocity, and acceleration output data in a form applicable to the various vehicle design, human tolerance, and compliance tasks for which the models have been developed.

A study has been conducted as an initial step in determining the differences observed between the motions of a living human impact sled test subject and a dummy test subject. The mechanism which is proposed for accomplishing this is the HSRI Two-Dimensional Mathematical Crash Victim Simulator. A series of measurements were taken on human test subjects, including classical and nonclassical anthropometric measurements, range of motion measurements for the joints, and maximum foot force measurements. A series of mathematical expressions has been used to predict body segment weight, centers of gravity, and moments of inertia using the results of the various body measurements. It was then possible to prepare a data set for use with the mathematical model.

This paper describes an injury criteria model implemented in computer language, and a restraint system effectiveness index for evaluating the degree to which the vehicle environment can prevent or reduce occupant injuries. The need for criteria of this type is based on the fact that if the degree of protection offered to a vehicle occupant by a restraint system or a vehicle interior (a function of the distribution and magnitude of the forces transmitted to the occupant) could be expressed in quantitative terms, then, more meaningful comparisons could be made between restraint configurations, and, areas of needed biomechanical research and statistical accident investigations could be more readily identified on the basis of the sensitivity of the results when the injury or effectiveness criteria are applied. The injury criteria model consists of three parts: 1.

This paper presents the various features and operational properties of a two-dimensional mathematical model of crash victim motions. The earliest forms of this model can be traced to the early 1960s. Developmental work on two-dimensional models then continued both within the automotive industry and in independent organizations such as the Highway Safety Research Institute (HSRI). The most recent product of this activity is the MVMA two-dimensional mathematical crash victim simulation developed at HSRI for the Motor Vehicle Manufacturers Association. The features of this model include: 1. An eight mass representation of the human body where contact between the crash victim and the vehicle is represented in terms of independent force-deformation properties of the victim and the vehicle. 2. An extensible multi-joint neck and a realistically flexible shoulder joint. 3. A real-line representation of the vehicle interior or exterior where shape is given as a network of points. 4.

Selected side-impact cases from the National Crash Severity Study (NCSS) were studied to determine similarities and differences between actual crashes and laboratory (sled) crash tests. Sled tests simulating side impact have been conducted almost exclusively at a 90° impact angle, so the NCSS cases analyzed were those with a near-side occupant and a reported 3 o'clock or 9 o'clock impact vector. Of the 91 cases studied, 51 were judged comparable to the laboratory situation. The remainder generally involved cars struck at a point remote from the passenger compartment, and often involved considerable rotation of the vehicle. Injuries for the 51 cases were tabulated by crash severity (Delta V) and were judged to be quite similar to those observed in laboratory (sled) tests at a slightly higher Delta V. Brief notes are appended concerning each of the reviewed cases.

Mathematical models of the human body subjected to an impact environment have been developed by many research groups in industry, government, private research organizations, and universities. In most cases, the models have not been verified by or compared with experimental results. The purpose of this paper is to show comparisons between the two- and three-dimensional crash victim simulators, which have been developed at the Highway Safety Research Institute of The University of Michigan, and front and side impact sled test results using anthropometric dummies.

A series of mathematical models of the interaction between an occupant and the interior of a vehicle is presented. The following parameter studies using an eight-mass, two-dimensional model are discussed: belt material properties, belt slack, belt geometric configuration, and comparison of seats with and without headrests in rear impact. In addition, it is demonstrated by example that simple mathematical models can perform a valuable service in laying the groundwork for more sophisticated analytical and experimental work as well as yielding short term results. Finally, three-dimensional models are discussed. It is shown that a three-mass, three-dimensional model is a logical extension of current simulation efforts in order to provide insight into occupant response in oblique and lateral impact as well as nonsymmetric restraint systems.

A large number of child seating and restraint systems are currently available on the market. This paper presents experimental data from impact sled tests in order to discuss the relative merits of several design concepts. Both seats and harnesses were considered in the study. They were attached to the vehicle by a variety of techniques including: a hookover seat, a hookunder seat, an adult lap belt, an auxiliary strap around the adult seat back, and combinations of these techniques. Tests were conducted with seats facing forward, sideways, 45 deg oblique, and rearward. Test subjects were commercially manufactured three-year anthropometric test devices and test dolls fabricated at The University of Michigan representing a 3-month-old infant. Head and chest accelerometers were mounted in the dummies. High-speed photographic coverage from the front and from the side was used to record the kinematics of the event.

This paper describes the methodology and results from a project involving development of anthropometrically based design specifications for a family of advanced adult anthropomorphic dummies. Selection of family members and anthropometric criteria for subject sample selection were based on expected applications of the devices and on an analysis of U.S. population survey data. This resulted in collection of data for dummy sizes including a small female, a mid-sized male, and a large male. The three phases of data collection included: 1. in-vehicle measurements to determine seat track position and seating posture preferred by the subjects for use in development of laboratory seat bucks; 2. measurement of subject/seat interface contours for fabrication of an average hard seat surface for use in the buck; and 3. measurement of standard anthropometry, seated anthropometry (in the buck), and three-dimensional surface landmark coordinates using standard and photogrammetric techniques.

This paper presents the concepts and first group of test results from a project designed to: 1. Quantify thoracic impact response using cadaver and baboon subjects;* 2. Compile analytical functions relating thoracic kinematic response to injuries observed in the experiments; and, 3. Define performance specifications insuring response fidelity between human and surrogate thoraxes. The experiments, which vary G-level, velocity, and direction of impact, utilize restraint systems including belts, airbags, and EA-columns. Resulting injuries are recorded at autopsy and an AIS rating assigned. Using the kinematic accelerometer data, injury-predictive functions are generated using statistical regression procedures. The utilization of project results in developing performance specifications for surrogate thoraxes is discussed in conclusion.

This paper discusses four aspects of computer modeling of restraint system performance: Components of restraint systems (both vehicle and restraint hardware components) Analytical representations of the system including lumped mass occupant computer codes (CAL3D, MADYMO, etc.) as well as finite element codes (PISCES™, PAM-CRASH™) Design applications of restraint system computer models Relations between auto makers and restraint system suppliers. To begin the discussion, the physical parameters of vehicles and restraint systems that affect occupant protection are listed. The purpose is to illustrate the difficulty in separating vehicle components from restraint system components. This is followed by a review of the current software for occupant simulation. This is complemented with a discussion of current development of finite element and finite difference representations of airbag restraints and occupants.

The purpose of this paper is to describe a combination of state-of-the-art detailed accident investigation procedures, computerized vehicle crash and occupant modeling, and biomechanical analysis of human injury causation into a method for obtaining enhanced biomechanical data from car crashes. Four accident cases, out of eighteen investigated, were selected for detailed reconstruction. Three were frontal impacts while the fourth was lateral. The CRASH II and MVMA 2-D analytical models were used in the reconstruction process. Occupant motions, force interactions with vehicle components, accelerations on the various body segments, and much other information was produced in the simulation process and is reported in this paper along with scene and injury data from the accidents.