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Anthropometric data relative to the pelvis have been obtained from X-rays of volunteers and Part 572 dummy, as well as pelvic bones of 28 human skeletons. Consequently, modifications in the pelvic portion of Part 572 dummy are proposed. These are based on the study in the difference of tendancy to submarining, the difference of the pelvic shape, and the abdominal flexibility between Part 572 dummy and the human being.

A theoretical study was conducted to prove that the Part 572 dummy submarines more easily than human cadavers because of their different pelvic shapes. The three-dimensional geometrical definition of the lap-belt was developed in this paper for the study of the submarining problem. It was found that not only the lap-belt angles from side view (β1) but also from the upper view in respect to the X-axis (β2) play a significant role in the submarining tendency for each side. The anti-submarining scale is defined by a coefficient which is a function of both angles β1, β2 and the orientation of the upper half of the pelvic notch. A series of sled tests was performed on human cadavers, the Part 572 dummy and the modified dummy. Good agreement was found between the present theory and the experimental results.

Current comparisons between active and passive restraint systems are still subjective and emotional. Statistical data, accident surveys, theoretical studies, and crash test results allow a technical analysis. Taking into account technological problems related to various devices and considering their economical incidence and their efficiency, it is possible to form an objective opinion. Conclusion is that the different principles of restraints are not opposed, but appear as successive steps of a same evolution.

This study aims at determining, with the maximum precision, the performance of the 3 point safety belt in different accident configurations, and more particularly in frontal collisions. For this purpose, two matched samples were taken from a file of 3000 accidents, analysed by a multidisciplinary study group. These samples of 100 front seat occupants wearing seat belts, and 100 not wearing seat belts were made up in such a manner that, for every belted occupant, corresponds an occupant not wearing a belt, the one and the other being in equivalent circumstances, using the following factors: Make and type of the vehicle Seat occupied Age (as far as possible) Direction of impact Violence of the impact (same class of ▵V and mean γ) Possible intrusion of passenger compartment Possible overload caused by a rear seat occupant Using this method of comparison, one can appreciate the effectiveness of the 3 point belt and explain the variations of effectiveness that appear in normal case studies.

With a view to improving the significance of the results obtained during the simulation of the response of a man exposed to severe acceleration, the authors have studied a simplified model of the head to thorax linkage provided with a suspension. Preliminary calculations or responses from the behavior of models provide coefficients of stiffness and damping. The authors propose to authenticate experimentally these values and to compare them with values of volunteers in similar situations exposed to moderate forces.

In order to reduce the number and severity of injuries to child occupants in car accidents, a great number of child restraint systems have been developed over the past years. Such systems must be adapted to the anthropometric characteristics of children and provide good protection; to achieve this, a knowledge of child tolerance to impact is required, but at present very little biomechanical data relating to children is available, especially for children in the first years of life. As the design, evaluation and certification of child restraint systems is performed with dummies and several dummy types are available- a relationship between dummy and expected child reactions must be identified. This paper, based on the work performed within the framework of the International Task Force on Child Restraint Systems*, proposes a comparison between child dummies and cadavers involved in identical experimental collisions, and restrained with child restraint systems.

Experimental simulations of car pedestrian collisions were conducted with production cars impacting a pedestrian dummy derived from PART 572 ; the tests were performed under well standardized conditions to try to limit experimental dispersions. The results corresponding to one series of tests are presented. The comparison of kinematical behaviour of this dummy and human subjects impacted by an other way under identical realistic test conditions displayed differences in kinematics and response at impact between these two kinds of surrogates. These differences can be explained largely by the greater stiffness of the PART 572 dummy, as compared to human subjects. For this reason, it was determined to duplicate the tests performed with the PART 572 dummy with a new series of tests with one APROD dummy, modified in a pedestrian version.

Experimental car-pedestrian collisions were performed with a modified PART 572 dummy and cadavers; they involved some reconstructions of real accidents. These collisions brought to light the differences between the kinematics and the impact responses when dummy and human subject are compared under identical and realistic test conditions to simulate a pedestrian struck sideways. These differences are mainly due to the overall relative stiffness of the PART 572 dummy when compared to cadavers. Same-type collisions were therefore carried out again with other dummies which were designed so as to simulate human response in lateral impact better; thus they were also assumed to display better kinematics as pedestrians. APROD and ONSER dummies were used; when compared to PART 572, their flexibility and deformation capabilities are greater, in particular as regards their thoraxes and shoulders.

One studies the conditions in which occurred side impacts having led to death of 369 car occupants. This sample is representative of the population of fatal collisions having occurred on French roads, in 1980. 28 % of killed were victims of collisions against another private car, 34 % struck a fixed obstacle, 21 % undergone a collision against a truck. The other types of collisions account for 17%. The performances to be reached in order to spare an important number of victims are of a high level. This is measured in function of the distribution of impact violences and occupants' ages.

The goal of this paper is to examine the validity of the Crashworthiness Rating Method (part of the New Car Assessment Program -NCAP - created by NHTSA) with reference to real-life accident data. A program was set up to verify the quality of predictive characteristics of vehicle models' real passive safety protection based on 35 mph crash tests against a 0° barrier. The Crashworthiness Rating Method was applied in the French context because seat belt use has been mandatory in France for over 10 years, and we have access to real-life accident files whose size and categories (type of vehicle model, crushed area, obstacle struck, seat occupied, age, and use of seat belt) allowed us to select cases appropriately and thoroughly. Additionally, the vehicle models which are representative of the French vehicle fleet were tested as if they were part of the NCAP.

Finite Element Models of the head are more and more often used to analyse brain injury risk during car crashes. Nevertheless, if the properties of head components such as brain, cerebral spinal fluid and membranes can be evaluated, the behaviour of the head has not yet been sufficiently validated as a whole. This paper deals with the development process of the model and the biomechanical data specifically generated for this purpose. Cadavers were re-pressurized and fully instrumented in order to measure 3D head dynamic, CSF pressure in various points of the subarachnoϊd space or in ventricles and intracerebral accelerations. For this last, a specific protocol has been developed; accelerometers have been designed to implant them at the right places. Tests were performed in various impact situations involving thorax and head segments with or without paddings.

Head neck responses from volunteer experiments, as obtained in various loading directions by the Naval Biodynamics Laboratory, represent a unique set of data in the field of biomechanical research. From this a set of volunteer thoracic (T1) and head responses were selected as a reference for this study. Two loading conditions were considered i.e. frontal and lateral directions. The objective of this study is to develop a finite element model of the human neck in frontal and lateral directions. The number of elements in the model was kept low in order to reduce the processing time for simulation and to minimize damping problems. The structure of the model is as follows: the vertebrae and the head were considered as rigid bodies. The interface between vertebrae such as discs and different ligaments are modelled by brick and spring elements. The passive action of the muscles are taken into account when determining the stiffness characteristics of the ligaments.

With drivers wearing 3-point seat belts, the head-steering-wheel impact occurs in most serious accidents, so inducing mainly face injuries. In a first part, the authors analyze the injuries observed in a sample of 1180 belted drivers involved in frontal collisions, making a distinction, mainly for facial impacts, between injuries related to the properly so-called face and those to the skull and brain and the different possible lesional correlations. In the second part are presented the results of work carried out in order to define a human face model adaptable to any type of Hybrid II or Hybrid III dummies' heads. The use of this model allows one to elaborate a new protection criterion for the face, destination of which should be to complete the head and skull protection criterion, such as the HIC (or another equivalent criterion which could possibly replace it).

In frontal impact, the occupantlbelt interaction is essential to obtain a good simulation of the occupant dynamic behaviour. Nevertheless, current mathematical models do not allow a realistic representation of this interaction to be obtained. Especially they are not adapted to simulate two important phenomena: the chest and pelvis deformation under the belt loading, and the belt sliding on the occupant. This paper deals with a tridimensional finite element model which allows an improved simulation of this interaction. The Hybrid III dummy, restrained by a 3-point retractor belt, was aimed, with a finite element program (RADIOSS). The model consisted of two parts: a deformable part representing, by means of springs and shell elements, the belt system, the thorax and the- pelvis; a rigid part representing, with rigid shell elements, the other components of the system. The belt was simulated by shell elements with a elasto-plastic material law.

In 1972, the Motor Vehicle Information and Cost Savings Act assigned to the Department of Transportation the mission of evaluating methods designed to yield a determination of a vehicle's damage susceptibility, degree of crashworthiness and ease of diagnosis and repair. Crashworthiness was defined as the protection a passenger vehicle affords its passengers against personal injury or death as a result of a motor vehicle accident. In 1978, NHTSA established a rating system for application to automobiles. The testing began on 1979 vehicles. The data of six years of tests has been acquired. The results of the New Car Assessment Program are reviewed

The Association PEUGEOT-RENAULT has explored several paths, technological as well as theoretical, regarding deployable methods of restraint. The first work was carried out using various kinds of American-made devices. At the same time, the Association PEUGEOT-RENAULT is actively participating in the development of French devices. This communication explains the present stage of these technological solutions, analyzes the performances obtained, and allows comparison of the latter with those obtained using seat belts.

Safety of children as car occupants raises a specific problem: it is necessary to take into account two factors which are particular to them: their very fast growth and their behavior, which corresponds to a need for movement. An analysis of statistical and accidentological data, points to the fact that whereas traffic accidents account for 25 % of adult deaths, they account for nearly 50 % of deaths for children (all kinds of road-users). Measures were adopted in France; such as the obligation for children of less than 10-years-old to travel on rear seats of cars and the definition of an homologation procedure for children restraint devices, with the aim of limiting the consequences of these accidents. The most common restraint devices look like little individual seats and are designed to protect young children (less than 3-years-old). Recently, new restraint devices, called “cushions”, were developed.

Biomecanical studies of the spine require data on the weight supported by each body segment studied. The only data available are from post mortem measurements on one old subject. The Barycentremetre, a gamma ray scanner, provides in vivo measurements. Barycentremetre measurements and full spine radiographs with a single reference system, were used to measure the weights of the arms and the remaining body weight supported by each anatomical level of 17 men and 11 women. Their weights are expressed in absolute terms (kg) and as a percentage of the total body weight. The vertebra level of the scapulohumeral joint is also provided. The range of the individual values may justify using of individual values or mean values supplemented by such other anthropometric values as the upper to lower body segment length ratio.

In 1344 car-to-car side collisions, the risk of serious or fatal injury to the occupants of struck vehicles seem to increase proportionally to the difference in mass ratios in favor of the striking vehicle. However, in-depth analysis of 63 collisions during which the impact occurred on the side panel of the passenger compartment reveals that the difference in mass ratios is not the principal determinant of injury severity. The frequency and severity of injuries correlates better with the amount of intrusion of the side panel, a type of intrusion which occurs almost systematically, and even at low impact speed, when the bumper and structure in front of the side rail of the striking car override the rocker panel of the struck car.

Protection criteria aside from deflection are defined on the basis of measurement functions taken at various but unique points on the thorax (rib, spinal column); these functions may also use two points (two ribs, for example) which results in deflection intervening as a criterion. The conditions imposed by these criteria result in different requirements for vehicle wall conditions and thorax model construction. Mathematical modeling of the vehicle wall-thorax collision is performed in order to compare possible criteria on this basis. Concurrently, a statistical analysis performed on a sampling of side impacts occurring with human subjects permits injury severity to be expressed by means of several functions whose predictive qualities are unequal. These functions include deflection, and their literal expression takes into account the state of the subjects' bone structure. The criteria produced by these predictive functions are used in the preceding mathematical model.