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No method based on experiments is convenient for evaluating globally the potential risk of a given vehicle for the whole population of pedestrians at risk, which encompasses the smallest children and the tallest adults simultaneously, when a large range of impact speeds has to be considered. Mathematical models are also inadequate, due to the large number of runs required for obtaining the probability of impact on each section of the front end profile. This paper describes first a recently improved mathematical method for defining the head trajectories yielded by experimental simulations or by a validated mathematical model. Then, a computer program is presented that simultaneously uses this method and statistical data concerning real accidents. The output of this program is a distribution of the impact probabilities for a given profile. The head impact velocities can be utilized for weighing the results. Possible improvements and application of this method are discussed.

PRAKIMOD has until now been mostly used for simulating pedestrian accidents. It is also a very convenient tool for studying frontal crashes, especially for determining the values of data that are not easily accessible from direct measurements. After a short description of the model and of the belt system, three examples of application are shown. The first one concerns the distribution of energy transfers from a dummy restrained by a shoulder belt and a knee bolster to the different parts of its environment and to the frontal structure of a car. The second one is an attempt to evaluate the respective influences of some parameters (such as the joint stiffnesses or mass distributions among the body parts) on the dummy's propensity for submarining. The third one concerns the problem of separating the effects of neck forces on the one hand, and of a direct impact on the steering wheel on the other hand.

This paper deals with frontal crash simulations with 3 point seat-belts, in which the conventional anthropomorphic test dummy has been replaced by a fresh unembalmed cadaver. Numerous test conditions have been used. Here are the complete results on the thorax for 31 cadavers in dynamic tests and 7 others in static tests. Specific interest in the thorax comes from the examination of injuries which has shown that, for a normal test, severe injuries are seldom located elsewhere than in the thorax. Methodology, which is the first described, states in particular how the cadavers are prepared with reconstitution of blood pressure and lung inflation and how skeleton strength is characterized. Among the results shown are those for the thorax autopsies, the corresponding seat belt restraint forces, some measurements with dummies used simultaneously and some data on recorded thorax deflections.

In France, as in other countries, accident research studies show that the greatest proportion of restrained occupants sustaining severe injuries and fatalities are involved in frontal impact (70% and 50% respectively). In severe frontal impacts with restraint occupants and where intrusion is not preponderant, the oldest occupants very often sustain severe thoracic injuries due to the seat belt. In the seventies, a few cars were equipped in France with load limiters and it was thereby possible to observe a relationship between the force applied and the occupant's age with regard to this thoracic risk. The reduction of intrusion for the most violent frontal impacts, through optimization of car deformation, usually translates into an increase in restraint forces and hence thoracic risks with a conventional retractor seat belt for a given impact violence.

EUROSID is the side impact dummy that has been designed and has now been almost completely developed by a group of European research laboratories working together under the auspices of the European Experimental Vehicles Committee (EEVC). It represents a bringing together of components and ideas from the three experimental sided impact dummies sponsored by the EEC1 as part of their Biomechanics Programme. These were produced by APR (Peugeot-Renault), ONSER, and MIRA. This paper describes the evolution of the EUROSID dummy and discusses the advances in biofidelity, the responses of its various components to impact, and the types of measurements it can record.

Much progress has been made in many countries during recent years in detailed research into road accidents. The analysis facilities used by research workers to describe in a common language the severity of injuries and the deformation the vehicles undergo are improving. Assessment of the constraints to which the occupants of crashed vehicles are exposed is still too approximate, despite the fact that this is essential to interpret the progress achieved in the field of safety and to make decisions concerning the future. The methods used to analyze and classify accidents must reside on unquestionable physical basis. This is why Renault and Peugeot have discarded the Equivalent Test Speed method, replacing it by the Speed Variation method (ΔV) and, more recently, analysis based on two parameters, namely the speed variation and the mean deceleration of the undistorted part of the vehicle.

From a file of real-world accidents analyzed by the Peugeot SA/Renault accident investigation team, 572 frontal impacts with a ΔV of more than 35km/h were extracted. These were described and classified on the basis of a large number of criteria that make it possible to compare the degree of representativeness of an oblique test and of a perpendicular test. This exhaustive descriptive method makes it possible to provide an objective basis for discussions concerned with the procedures of a homologation test.

Since July 1, 1973, the wearing of seat belts by front seat occupants is compulsory in France. This requirement is respected by 60 to 90% of motorists, depending on the type of road. If seat belts were not worn, a 55% increase in fatalities for front seat occupants would be observed. On the other hand, if seat belts were worn by occupants in all seats 100% of the time, fatalities would be reduced by another 30%. Improvements of the seat belt over the past ten years have had a significant influence in the following areas: - Incentives for wearing the belts - Limitation of belt stretch and spool-out - Reduction of the number of submarining cases. In this paper, emphasis is put on the levels of performance which no other sytem has been able to attain, or even equal, and which result in practically guaranteeing protection against the risk of ejection, especially in a side impact or rollover.

Accidentological studies show, firstly, what kind of injuries are sustained by seat-belt wearers in frontal collisions, to abdomen, lumbar spine and lower members and, second, how to determine their frequencies and severities. Corresponding data are presented. Then, a synthesis is made in which the results of extensive cadaver testing more than 300 human subjects-are examined with particular emphasis on the abdominal injuries, and on the association of injuries, such as lumbar spine injuries. Causation is particularly looked at. This experimental survey is completed by the results of specialized testing in abdominal tolerance when submarining occurs. These two surveys enable the development of protection. Finally, former attempts for defining an abdominal protection criterion are reviewed and a final definition for such a criterion is presented and justified.

In order to obtain data about human head tolerance, the LPB-APR has conducted some experimentations with volunteer boxers. Five fights, i.e. fifteen rounds were carried out. Such research was undertaken because they expose themselves, in their normal body activities to direct head impacts. In an earlier publication, the methodology used for these experimentations was presented. The scope of this paper is to present the results obtained : the head accelerations. the head kinematics, the physiological effects. The findings showed that the angular accelerations were in all cases higher than 3500 rd/s2 exceeding the values considered as tolerance limit for volunteers given in the literature already available. The maximum angular velocity was 48 rd/s with a corresponding angular acceleration of 13600 rd/s2.

Collisions between vehicles and pedestrians are analyzed, in conjunction with a bidisciplinary “pedestrian” investigation, by simulating accidents using adult and child dummies. A series of experimental collisions were carried out at varying impact speeds with a sample of vehicles representative of the various front-end profiles of vehicles at present running on the roads, the purpose being to study how these profiles affect the kinematics of the adult and child and to define the risks of injury during the different phases of the accident. The degrees of severity of the impact against the vehicle and the ground are compared and head impact speeds analyzed. Countermeasures are proposed and an initial evaluation made using a cadaver.

Data about severe coach accidents are still limited. More knowledge in this field is required to define safety priorities that designers and manufactures need to consider in future vehicles. Despite the good safety level of coaches, some spectacular accidents nevertheless occur causing serious injuries and death to the users, and these are often brought to the public's attention by the media. This survey is based on all the fatal coach accidents that occurred in France between 1978 and 1984. The paper describes the causes and accident configurations and analyzes the injury mechanisms. Countermeasures are discussed, and possible ways of minimizing occupant injuries, related to strength of front end structures, seat back improvements, window retention, and fire protection, are suggested

This report describes the results of 42 tests involving direct impacts on the head, performed on fresh, unembalmed, perfused cadavers, helmeted or not helmeted, by means of a free-fall procedure. Three main kinds of impact were investigated: frontal, temporal-parietal, and frontal-facial. The results yield a typology of lesions (associated with various test conditions) that differs from the one described in earlier, similar reports published by A.M. Nahum and R.L. Stalnaker. The measurements confirm a tolerance level of HIC>1500 in the case involving skull impacts under the conditions specified in the text.

Car-pedestrian accidents were selected with reference to criteria like relevance in terms of injury severities representativity and reproducibility aiming to as accurate as possible reconstructions by dummy and cadaver tests. Parameters necessary for performance of these reconstructions were evaluated from the data of accident investigation teams. Preliminary tests were performed by research departments of automobile manufacturers to check the estimated conditions of these accidents before performing their reconstructions. A particular aim was to obtain insights into the mechanisms leading to injuries in pedestrian accidents; more generally reconstructing actual accidents is a privilegied approach to determine human tolerance limits and the corresponding protection criteria on dummies; the injuries resulting from the actual accidents are consequently compared with the data measured on dummies and cadavers in the reconstruction experiments.

Based on morphological and biomechanical study of 146 human skulls, a parameter has been established to characterize the resistance of the skulls of subjects used in experiments, the so-called “Skull Bone Condition Factor” (SBCF). The analysis of ten cadaver lateral drop tests has allowed to point out the influence of this parameter on the prediction of brain injury through HIC. This paper intends to establish a simple way to integrate the SBCF in the Head Injury Criterion with the aim of allowing comparisons between cadaver tests and of having a more realistic means of prediction of brain injuries.

A large number of experiments involving cadavers - including real-world-accident reconstructions - have been performed for the purpose of enhancing the state of knowledge concerning tolerance levels and protection criteria relevant to side-impact conditions. However, the scatter of the findings, as well as the considerable differences in injury severity levels (differences that cannot be accounted for by age differences alone) have limited the conclusions that it was possible to draw from these investigations in terms of criteria, mainly concerning thoracic protection. The major cause of scatter is the considerable differences in skeleton quality between subjects. Analysis of the rib characterization test findings made it possible to define a thoracic resistance index enabling the establishment of a classification of subjects. This index, which was validated with our sample, allowed us to evaluate the pertinence of the various side-impact protection criteria considered.

The data presented in this paper were yielded by tests performed on unembalmed human cadavers fitted with three-point seat belts and subjected to frontal collisions. The purpose is to define one or more functions predictive of thoracic injuries to cadavers whose rib “resistance” is known (i.e. BCF parameter (1)*). These functions predict the number of rib fractures and the thoracic AIS in terms of : anthropometrical data on the cadavers, data representative of the thoracic resistance of the cadavers and physical parameters arising from the deceleration pulses measured on the cadaver vertebrae during the occurrence of impact. By integrating the BCF data which characterize the ribs of the population exposed to the risk of thoracic injury, it is possible satisfactorily to define the tolerance of living road users, in terms of their age. Provided that maximum admissible injury level, and the age for which this limit is required are set, a tolerance criterion can then be defined.

So far, analysis of real-world crashes has not made it possible to evaluate the occupant change of velocity in side impact. This change of velocity is the most pertinent of the lateral-collision violence parameters when occupants are exposed to intrusion by car bodies. The present paper describes a method for calculating this parameter, and includes a description of the data that must be collected concerning real-world crashes in order to enable its application. The validity of this method is demonstrated by its application to a series of experimental collisions. The results are highly correlated to the values resulting from the integration of the accelerations found for the pelvis and thorax. The method is then applied to 60 real-world car-to-car side collisions from the accident survey.

THE FREQUENCY AND SEVERITY OF LESIONS SUSTAINED BY THE OCCUPANTS OF CARS IMPACTED LATERALLY depend upon the main following factors: impact localization, intrusion into passengers' compartment, car speed variation, direction of occupant trajectory, objects contacted by the various body areas. 296 lateral impacts are being described hereunder by means of factors below. Consequences are drawn therefrom as to the coming improvement of occupant protection taking account of the current state of the art in Biomechanics and automobile technique. IN COMPARISON WITH THE PROGRESS achieved with a view to improving occupant protection against frontal impact, the knowledge available on the lateral impact and the methods for reducing the severity thereof are very poor. In as much as the results achieved in biomechanics up to this date are known, there is still much to do in this field. Mc Elhaney (1)* already stressed the fact in 1971 after Snyder (2).

Biomechanical studies related to the head have been mainly directed towards the determination of cerebral tolerance to impact in the absence of fracture. However, the frequency of skull trauma producing complex fractures and cerebral lesions linked to these fractures should be taken into consideration. On a human being, impacts under similar mechanical conditons can produce either fatal encephalic lesions without fractures or skull fractures with encephalic lesions if the subject has a different skull morphology. A sample of 146 subjects has been studied to determine the relation between the morphological characteristics of the skulls (weight of the skull cap, thickness, weight of the cranial skeleton…), their mineralization. The mechanical tests were performed on bone fragments (bending and shearing tests). Nine accelerometers were used during the experiments of various types of impacts. The results were computerized. The skull fractures observed (a total of 45) are described.