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One main objective of the EU-Project SENIORS is to provide improved methods to assess thoracic injury risk to elderly occupants. In contribution to this task paired simulations with a THOR dummy model and human body model will be used to develop improved thoracic injury risk functions. The simulation results can provide data for injury criteria development in chest loading conditions that are underrepresented in PMHS test data sets that currently proposed risk functions are based on. To support this approach a new simplified generic but representative sled test fixture and CAE model for testing and simulation were developed. The parameter definition and evaluation of this sled test fixture and model is presented in this paper. The justification and definition of requirements for this test set-up was based on experience from earlier studies. Simple test fixtures like the gold standard sled fixture are easy to build and also to model in CAE, but provide too severe belt-only loading. On the other hand a vehicle buck including production components like airbag and seat is more representative, but difficult to model and to be replicated at a different laboratory. Furthermore some components might not be available for physical tests at later stage. The basis of the SENIORS generic sled test set-up is the gold standard fixture with a cable seat back and foot rest. No knee restraint was used. The seat pan design was modified including a seat ramp. The three-point belt system had a generic adjustable load limiter. A pre-inflated driver airbag assembly was developed for the test fixture. Results of THOR test and simulations in different configurations will be presented. The configurations include different deceleration pulses. Further parameter variations are related to the restraint system including belt geometry and load limiter levels. Additionally different settings of the generic airbag were evaluated. The test set-up was evaluated and optimized in tests with the THOR-M dummy in different test configurations. Belt restraint parameters like D-ring position and load limiter setting were modified to provide moderate chest loading to the occupant. This resulted in dummy readings more representative of the loading in a contemporary vehicle than most available PMHS sled tests reported in the literature. However, to achieve a loading configuration that exposes the occupant to even less severe loading comparable to modern vehicle restraints it might be necessary to further modify the test set-up. The new generic sled test set-up and a corresponding CAE model were developed and applied in tests and simulations with THOR. Within the SENIORS project with this test set-up also volunteer and PMHS as well as HBM simulations are performed, which will be reported in other publications. The test environment can contribute in future studies to the assessment of existing and new frontal impact dummies as well as dummy improvements and related instrumentation. The test set-up and model could also serve as a new standard test environment for PMHS and volunteer tests as well as HBM simulations.
Pedestrians represent about 20% of the overall fatalities in Europe- road traffic accidents. In this paper a methodology is proposed to understand why the numbers are so high, especially in the south of Europe and particularly in Portugal, . First a detailed statistical analysis using Ordinal Logistic Regression model (OLR) was applied to the gathered data from all Portuguese accidents with victims in the period 2010-2012. In a second stage accident reconstruction computational techniques using pedestrian biomechanical models are used to evaluate the accident conditions that lead to the injuries, such as the speed and the impact location. For biomechanical injury criterions, the AIS (Abbreviated Injury Scale), the HIC (Head Injury Criterion) and other injury criterions based on the resulting accelerations in the pedestrian's body are used. The statistical model reported that there were several predictors that significantly influenced the pedestrian injury severity in the event of a road accident, such as Pedestrian's age, Pedestrian's gender, Vehicle Design/Category or Driver's gender. The use of injury scales and biomechanical criterions in in-depth investigation of road accidents, such as AIS, can significantly improve the quality of the reconstruction process.
Description of road traffic related knee injuries in published investigations is very heterogeneous. The purpose of this study was to estimate the risk of knee injuries in real world car impacts in Germany focusing vulnerable road users (pedestrians, bicyclists and motorcyclists) and restrained car drivers. The accident research unit analyses technical and medical data collected shortly after the accident at scene. Two different periods (years 1985-1993 and 1995-2003) were compared focusing on knee injuries (Abbreviated Injury Scale (AISKnee) 2/3). In order to determine the influences type of collision, direction and speed as well as the injury pattern and different injury scores (AIS, MAIS, ISS) were examined. 1.794 pedestrians, 742 motorcyclists, 2.728 bicyclists and 1.116 car drivers were extracted. 2% had serious ligamentous or bony injuries in relation to all injured. The risk of injury is higher for twowheelers than for pedestrians, but knee injury severity is higher for the latter group. Overall the current knee injury risk is low and significant reduced comparing both time periods (27%, p<0,0001). Severe injuries (AISKnee 2/3) were below 1%). Improved aerodynamic design of car fronts reduced the risk for severe knee injuries significantly (p=0,0015). Highest risk of injury is for motorcycle followed by pedestrians, respectively. Knee protectors could prevent injuries by reducing local forces. The classically described dashboard injury was rarely identified. The overall injury risk for knee injuries in road traffic is lower than estimated and reduced comparing both periods. The aerodynamic shape of current cars compared to older types reduced the incidence and severity of knee injuries. Further modification and optimization of the interior and exterior design could be a proper measurement. Classic described injury mechanisms were rarely identified. It seems that the AIS is still underestimating extremity injuries and their long term results.
Pelvic fracture, cracking or breaking of a portion of the pelvis are extremely common injuries in the side impact collisions of motor vehicles. Due to both its shape and structural architecture, mechanics of the pelvic bone is complicated. There is a lack of knowledge regarding the dynamic behavior of the pelvis and its biomechanical tolerance under impact environment. Hence this study is aimed at the understanding of the mechanical response of the human pelvis with three-dimensional finite element (FE) models, under side impact load, applied through a structure, equivalent to a car door. The door structure was modeled, considering few layers, consisting of foam (Styrodur®, 3035 CS), plastic (UHMWPE), steel, glass and steel, putting them in series. A soft tissue layer (equivalent to fat) was also considered on the greater trochanter location. These FE models (with and without the car door structure) were analyzed with ANSYS-LS-DYNA-® dynamic finite element software to compare the effect of the car door padding system for shock absorption. It was observed that with proper combination of shock absorbing material (foam, etc.) and its thickness, the transmission of impact load to the body part (pelvis, etc.) from the outer surface of the car door could be reduced.
In 2012 the fifth ESAR conference (Expert Symposium on Accident Research) was held in Hannover. ESAR is an international convention of experts, who analyze traffic accidents all over the world and discuss their results in this context, conducted at the Medizinische Hochschule Hannover every 2 years. It connected representatives of public authorities, engineers in automotive development and scientists and offers a forum with particular emphasis on In-Depth-Analyses of accident statistics and accident analyses. Special focus is placed on research on the basis of so-called "In-Depth-Accident-Investigations" [data collections at the sites of the accidents], which are characterized by extensive documentations of the sites of the accidents, of the vehicles as well as of the injuries, encompassing several scientific fields. ESAR aims at a multi-disciplinary compilation of scientific results and at discussing them on an international, scientific level. It is thus a scientific colloquium and a platform for exchanging information for all accident researchers. Experiences in accident prevention as well as in the complex field of accident reconstruction are stated and new research fields are added. Existing results of long-term research work in Europe, the US, Australia and Japan include different infrastructural correlations and give findings on population, vehicle population and driver characteristics, which offer a basis for recommendations to be derived and measures for increasing road safety.
Im Jahr 2004 fand an der Medizinischen Hochschule Hannover die erste ESAR-Konferenz (Expert Symposium on Accident Research) statt. Die Idee einer internationalen Konferenz war aus der Notwendigkeit entstanden, diejenigen Experten zusammen zu bringen, die weltweit tätig sind und Verkehrsunfälle wissenschaftlich analysieren, um ihre Ergebnisse gemeinsam zu diskutieren und einem Zielpublikum von Behördenvertretern, Entwicklungsingenieuren der Automobilindustrie und anderen Wissenschaftlern darzubringen. Die durch Professor Otte initiierte und nun zum vierten Male organisierte Konferenz fand eine breite Akzeptanz und ist mittlerweile Bestandteil einer Konferenzlandschaft mit Zielvorträgen von der Fahrzeugsicherheit bis hin zur Verletzungsanalyse und den Unfallursachen. ESAR kann als wissenschaftliches Kolloquium und Plattform für einen Informationsaustausch der Unfallforscher angesehen werden, die sich speziell mit Methoden der Unfalluntersuchung, mit Verletzungsmechanismen und der Bewertung von Verletzungen, Unfallursachen und anderen Bereichen der statistischen Unfalldatenanalyse befassen. Experten aus den Bereichen der Medizin, der Verkehrspsychologie und der Technik sowie Vertreter zuständiger Behörden kommen hier zusammen, um die Erfahrungen in der Unfallprävention und der Unfallrekonstruktion zu diskutieren und um der Forschung neue Felder zu eröffnen. Neben den Belangen der Europäischen Gemeinschaft werden auch die weltweit zu registrierenden hohen Verletztenzahlen berücksichtigt. Wissenschaftliche Vorträge aus aller Welt tragen dazu bei, geeignete Maßnahmen und Methoden zur Analyse und drastischen Verringerung der Zahl der bei Verkehrsunfällen Getöteten zu entwickeln. Die Zusammensetzung des Teilnehmerkreises dieser wie früherer ESAR-Konferenzen hat längst eine über Europa hinausgreifende Internationalitaet erreicht und bietet daher einen aufschlussreichen Überblick über die verschiedenen Standards bestehender Verkehrssicherheit und unterschiedlichen Unfallszenarien und über die Anforderungen an die Unfallanalysen. Die Ergebnisse langjähriger Forschungsarbeiten in Europa, USA, Australien und asiatischen Ländern beinhalten unterschiedliche infrastrukturelle Zusammenhänge und geben Erkenntnisse über Population, Fahrzeugbestand und Fahrereigenschaften. Derartige Informationen bilden eine exzellente Basis für abzuleitende Empfehlungen und Maßnahmen für die Erhöhung der Verkehrssicherheit international.