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Technical Paper

Abdominal Twin Pressure Sensors for the Assessment of Abdominal Injuries in Q Dummies: In-Dummy Evaluation and Performance in Accident Reconstructions

The APTS ability to detect abdominal loading in sled tests was also confirmed, with peak pressures typically below 1 bar when the belt loaded only the pelvis and the thorax (appropriate restraint) and values above that level when the abdomen was loaded directly (inappropriate restraint). Then, accident reconstructions performed as part of CASPER and previous EC funded projects were reanalyzed.
Technical Paper


The method used in this project was to collect data from accident investigations and from reconstruction crash tests in order to determine the physical parameters (forces, accelerations and deformations on the child) which correspond to the various child injury mechanisms. ...In particular, data from the 56 accident reconstructions are presented and injury criteria are evaluated against reconstruction results. ...Child restraint systems (CRS) for cars are intended to protect children in the case of a car accident. Unfortunately their effectiveness is still too low: in the range 30–50 % when it would be expected to be much higher.
Technical Paper

Laboratory Reconstructions of Real World Frontal Crash Configurations Using the Hybrid III and THOR Dummies and PMHS

Load-limiting belt restraints have been present in French cars since 1995. An accident study showed the greater effectiveness in thorax injury prevention using a 4 kN load limiter belt with an airbag than using a 6 kN load limiter belt without airbag. ...The sled configuration and the deceleration law correspond to those observed in the accident study. Restraint conditions evaluated are the 6 kN load-limiting belt and the 4 kN load-limiting belt with an airbag. ...The injury results of the PMHS tests showed the same tendency as the accident study. Some of the criteria proposed in the literature did not show a better protection of the 4 kN load limiter belt with airbag restraint, in particular thoracic deflection maxima for both dummies.
Technical Paper

Neck Injury Criteria for Children from Real Crash Reconstructions

To realize this second part, real crash reconstructions were performed, in order to correlate observed injuries with recorded parameters on dummies. ...This paper mainly presents four real crashes with the corresponding reconstructions. A special analysis of injury mechanisms in relation with their respective pertinent parameters is then proposed.
Technical Paper

Relation Between Sacroilium and Other Pelvic Fractures Based on Real-World Automotive Accidents

The study firstly aimed at looking whether sacroilium (SI) fractures could be sustained as unique pelvic injuries in side impact real world automotive accidents. Secondarily, the sacroilium fractures observed in conjunction with other pelvic fractures were analyzed to investigate the existence of injury association patterns. ...Two real world accident databases were searched for SI fractures. The occupants selected were front car passengers older than 16, involved in side, oblique or frontal impact, with AIS2+ pelvic injuries. ...The first database is an accident database composed of cases collected in France by car manufacturers over a period of approximately 40 years.
Technical Paper

The Programmed Restraint System - A Lesson from Accidentology

Accident studies show that frontal collisions, both as regards the number of people killed and those seriously-injured, are by far the type of crash with the most serious consequences. ...A first step in this reduction was taken in 1995 with the introduction of the first-generation Programmed Restraint System (PRS), with a seat-belt force threshold of 6 kN; thirty seven frontal accident cases involving this type of restraint were investigated. The corresponding data, crash severities and occupant injuries, are reported in this paper.
Technical Paper

Dynamic Biomechanical Dorsiflexion Responses and Tolerances of the Ankle Joint Complex

This paper presents comprehensive dorsiflexion responses and tolerances obtained from two types of dynamic tests on whole cadavers conducted at the Renault/PSA Laboratory of Accidentology and Biomechanics (LAB): sled tests and sub-system tests. In all the experiments (on whole cadavers), forces and moments within the ankle joint were accurately measured by means of a custom-designed 6-axis load cell implanted in the tibia, leaving all surrounding musculature intact. The results derived from both the sled tests and the subsystem tests are very similar. Moment-rotation curves are provided for the ankle joint. The force in the Achilles tendon which is not directly measured is calculated using the forces applied to the foot and the forces measured in the tibia.
Technical Paper

Comparison of the Thorax Dynamic Responses of Small Female and Midsize Male Post Mortem Human Subjects in Side and Forward Oblique Impact Tests

Despite the increasing knowledge of the thorax mechanics in impact loadings, the effects of inter-individual differences on the mechanical response are difficult to take into account. For example, the biofidelity corridors for the small female or large male are extrapolated from the midsize male corridors. The present study reports on the results of new tests performed on small female Post Mortem Human Subjects (PMHS), and compares them with test results on midsize male PMHS. Three tests in pure side impact and three tests in forward oblique impact were performed on the thorax of small female specimens. The average weight and stature were 43 kg and 1.58 m for the small female specimens. The initial speed of the impactor was 4.3 m/s. The mass and the diameter of the impactor face were respectively 23.4 kg and 130 mm. The instrumentation and methodology was the same as for the tests published in 2008 by Trosseille et al. on midsize male specimens.
Technical Paper

Kinematics and Dynamics of the Pelvis in the Process of Submarining using PMHS Sled Tests

This study focused on a better understanding and characterization of the submarining phenomenon that occurs in frontal crashes when the lap belt slides over the anterior superior iliac spine. Submarining is the consequence of the pelvis kinematics relative to the lap belt, driven by the equilibrium of forces and moments applied to the pelvis. The study had two primary purposes; the first was to provide new PMHS data in submarining test configurations, the second was to investigate the Hybrid II and Hybrid III dummies biofidelity regarding submarining. Several Post Mortem Human Subject (PMHS) studies have been published on this subject. However, the lack of information about the occupant initial positioning and the use of car seats make it difficult to reconstruct these tests. Furthermore, the two dummies are rarely compared to PMHS in submarining test configurations. A fifteen frontal sled test campaign was carried out on two Anthropomorphic Test Devices (ATDs) and nine PMHS.
Technical Paper

Validation Study of a 3D Finite Element Head Model Against Experimental Data

Very few finite element head models have been validated as required before being used to study brain injury mechanisms. This paper deals with the validation study of a 3D head model [1] against five cadaver tests [2]. It evaluates the current model ability to simulate brain responses and draws the research lines to improve it. Velocities on the closed rigid skull model were fixed to duplicate experimental applied loads. Validation parameters were constituted by three intra-cranial accelerations, three epidural pressures and in two cases, two extra pressures in the ventricles. The model response matched experimental results in terms of trend but presented significant oscillations. Moreover, there was a shift between experimental and numerical pressure curves. Brain material damping was introduced but numerical oscillations were slightly reduced.
Technical Paper

Side Impact: Influence of Impact Conditions and Bone Mechanical Properties on Pelvic Response Using a Fracturable Pelvis Model

This study aimed at determining the influence of impact conditions and occupant mechanical properties on pelvic response in side impact. First, a fracturable pelvis model was developed and validated against dynamic tests on isolated pelvic bones and on whole cadavers. By coupling a fixed cortical bone section thickness within a single subject's pelvis and across the population with a parametric material law for the pelvic bone, this model reproduced the pelvic response and tolerance variation among individuals. Three material laws were also identified to represent fragile, medium and strong pelvic bones for the 50th percentile male. With this model, the influence of impact mass, velocity and surface shape on pelvic response was examined. Results indicated that the shape difference between four main impactors reported in the literature has little effect on the pelvic response.
Technical Paper

Assessment of the Pubic Force as a Pelvic Injury Criterion in Side Impact

In the literature, injuries at the ischio or ilio pubic ramus level are reported to occur to approximately ¾ of the occupants injured at the pelvis during side impact. Assuming that the load going through the pubis was a good indicator of the ramus stress, the pubic force was widely accepted as a protection criterion for pelvic fractures on side impact dummies. However, no data regarding the actual loads going through the pubis is currently available in the literature for Post Mortem Human Subjects (PMHS) in dynamic conditions. The goal of this study was to determine pelvic biofidelity specifications in terms of load path, to evaluate the pertinence of the pubic force as a criterion, and to develop a pelvic injury risk curve as a function of the pubic force. For that purpose, a pubic load cell was developed for PMHS use, and 16 side impact tests were performed on 8 PMHS using boundary conditions similar to impactor tests and sled tests reported in the literature.
Technical Paper

A Comparison of Sacroiliac and Pubic Rami Fracture Occurrences in Oblique Side Impact Tests on Nine Post Mortem Human Subjects

The WorldSID dummy can be equipped with both a pubic and a sacroiliac joint (S-I joint) loadcell. Although a pubic force criterion and the associated injury risk curve are currently available and used in regulation (ECE95, FMVSS214), as of today injury mechanisms, injury criteria, and injury assessment reference values are not available for the sacroiliac joint itself. The aim of this study was to investigate the sacroiliac joint injury mechanism. Three configurations were identified from full-scale car crashes conducted with the WorldSID 50th percentile male where the force passing through the pubis in all three tests was approximately 1500 N while the sacroiliac Fy / Mx peak values were 4500 N / 50 Nm, 2400 N / 130 Nm, and 5300 N / 150 Nm, respectively. These tests were reproduced using a 150 kg guided probe impacting Post Mortem Human Subjects (PMHS) at 8 m/s, 5.4 m/s and 7.5 m/s.
Technical Paper

Statistical Simulations to Evaluate the Methods of the Construction of Injury Risk Curves

Several statistical methods are currently used to build injury risk curves in the biomechanical field. These methods include the certainty method (Mertz et al. 1996), Mertz/Weber method (Mertz and Weber 1982), logistic regression (Kuppa et al. 2003, Hosmer and Lemeshow 2000), survival analysis with Weibull distribution (Kent et al. 2004, Hosmer and Lemeshow 2000), and the consistent threshold estimate (CTE) (Nusholtz et al. 1999, Di Domenico and Nusholtz 2005). There is currently no consensus on the most accurate method to be used and no guidelines to help the user to choose the more appropriate one. Injury risk curves built for the WorldSID 50th side impact dummy with these different methods could vary significantly, depending on the sample considered (Petitjean et al. 2009). As a consequence, further investigations were needed to determine the fields of application of the different methods and to recommend the best statistical method depending on the biomechanical sample considered.
Technical Paper

Investigation of Pelvic Injuries on Eighteen Post Mortem Human Subjects Submitted to Oblique Lateral Impacts

The aim of this study was to investigate the sacroiliac joint injury mechanism. Two test configurations were selected from full scale car crashes conducted with the WorldSID 50th dummy resulting in high sacroiliac joint loads and low pubic symphysis force, i.e. severe conditions for the sacroiliac joint. The two test conditions were reproduced in laboratory using a 150-155 kg guided probe propelled respectively at 8 m/s and 7.5 m/s and with different shapes and orientations for the plate impacting the pelvis. Nine Post Mortem Human Subject (PMHS) were tested in each of the two configurations (eighteen PMHS in total). In order to get information on the time of fracture, eleven strain gauges were glued on the pelvic bone of each PMHS. Results - In the first configuration, five PMHS out of nine sustained AIS2+ pelvic injuries. All five presented sacroiliac joint injuries associated with pubic area injuries.