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For more than a decade, ADAC accident researchers have analysed road accidents with severe injuries, recording some 20,000 accidents. An important task in accident research is to determine the causative factors of road accidents. Apart from vehicle engineering and human factors, accident research also focuses on infrastructural and environmental aspects. To find out what accident scenarios are the most common in ADAC accident research and what driver assistance systems can prevent them, our first task was to conduct a detailed accident analysis. Using CarMaker, we performed a realistic simulation of accident scenarios, including crashes, with varying parameters. To begin with, we made an initial selection of driver assistance systems in order to determine those with the greatest accident prevention potential. One important finding of this study is that the safety potential of the individual driver assistance systems can actually be examined. It also turned out that active safety offers even much more potential for development and innovation than passive safety. At the same time, testing becomes more demanding, too, as new systems keep entering the market, many of them differing in functional details. ADAC will continue to test all driver assistance systems as realistically as possible so as to be able to provide advice to car buyers. Therefore, it will be essential to develop and improve test conditions and criteria.
The development of tyre- and truck-manufacturers leads to the direction to introduce wide base single tyres (size 495/45R22,5) instead of twin tyres on the driving axle of trucks, tractors and busses. To study the driving behaviour and safety of various trucks and units with different tyre combinations and loading conditions was the aim of the study. A computer-aided simulation was used for this investigation. Drive tests with a 40 t unit with prototype single tyres on the drive axle were carried out to verify the simulation. Alterations in driving behaviour and driving safety are mainly dependent on the tyre cornering stiffness. The prototype wide single tyres had a higher lateral stiffness which leads to a higher degree of under-steering (safer driving behaviour). The altered spring base on the drive axle had no influence on the side- tilt stability of vehicle combinations but the solo truck profited from the higher rear axle roll stiffness (less danger for roll-over accidents). As far as the driving safety is concerned nothing speaks against wide base tyres on the drive axle. The simulation of a tyre defect in a bend (assuming 40% of the max. transferable side force for the flat tyre) showed no increased danger using wide single tyres. Later driving tests showed however the need of tyre run flat possibilities to avoid jack-knifing of road trains. Also tyre pressure monitoring systems and electronic stability programs for the trucks are advised.
Accident research 2.0: New methods for representative evaluation of integral safety in traffic
(2013)
BMW has developed a procedure for rating Advanced Driver Assistance Systems (ADAS) benefits that integrates two distinct tools. The tool "S.A.F.E.R." is designed to analyze the pre-crash phase. The aim of S.A.F.E.R. is to simulate all relevant processes in sufficient detail to obtain reproducible estimates of key indicators (effectiveness, false positives, etc.). The relevant processes include not only traffic and vehicle dynamics, but also environmental and most importantly human factors. Representative distributions of factors and parameters are obtained by taking the stochastic variation of all relevant parameters into account in the simulations. The second tool, known as "ICOS", has been designed to provide a high-resolution, high-fidelity description of crash phase dynamics. If one converts the outputs of stochastic simulation into inputs for crash dynamics, the result is a comprehensive description of exactly how a safety system can reduce injuries. Applications currently focus on high-fidelity simulation of individual crashes in order to enhance our understanding and optimization of connected safety systems. An integrated simulation process thus allows an exact prediction of the effectiveness in individual cases in terms of injury severity. The development and rating of integral safety need to reflect the true efficiency in the field. The integrated approach described here could provide a valid and reproducible basis for rating connected systems of active and passive safety. In particular, "virtual experiments" using a traffic-based approach and incorporating models of all relevant processes constitute an essential element of the approach.
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.