Search Results

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.

This paper is related to the pedestrians struck by a vehicle. From the results of multiple runs performed with a previously validated mathematical model, an equation is defined which describes the trajectories of their heads. When the distribution in heights of the pedestrians and the distribution in speeds of the colliding vehicles are taken into account, this equation enables the prediction of the head impact probability for the sundry areas of the front end of the vehicle, according to its profile.

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.

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.

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.

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.