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For the estimation of the benefit and effect of innovative Driver Assistance Systems (DAS) on the collision positions and by association on the accident severity, together with the economic benefit, it becomes necessary to simulate and evaluate a variety of virtual accidents with different start values (e.g. initial speed). Taken into account the effort necessary for a manual reconstruction, only an automated crash computation can be considered for this task. This paper explains the development of an automated crash computation based on GIDAS. The focus will be on the design of the virtual vehicle models, the method of the crash computation as well as exemplary applications of the automated crash computation. For the first time an automated crash computation of passenger car accidents has been realized. Using the automated crash computation different tasks within the field of vehicle safety can be elaborated. This includes, for example, the calculation of specific accident parameters (such as EES or delta-V) for various accident constellations and the estimation of the economic benefit of DAS using IRFs (Injury Risk Functions).
For a number of EU regulatory acts Virtual Testing (VT) is already allowed for type approval (see Commission Regulation No. 371/2010 of 16 April 2010 amending the Framework Directive 2007/46/EC). However, only a very general procedure on how to apply VT for type approval is provided. Technical details for specific regulatory acts are not given yet. The main objective of the European project IMVITER (IMplementation of VIrtual TEsting in Safety Regulations) was to promote the implementation of VT in safety regulations. When proposing VT procedures the new regulation was taken into account, in particular, addressing open issues. Special attention was paid to pedestrian protection as pilot cases. A key aspect for VT implementation is to demonstrate that the employed simulation models are reliable. This paper describes how the Verification and Validation (V&V) method defined by the American Society of Mechanical Engineers was adapted for pedestrian protection VT based assessment. or the certification of headform impactors an extensive study was performed at two laboratories to assess the variability in calibration tests and equivalent results from a set of simulation models. Based on these results a methodology is defined for certification of headform impactor simulation models. A similar study was also performed with one vehicle in the type approval test setup. Its bonnet was highly instrumented and subjected to 45 impacts in five different positions at two laboratories in order to obtain an estimation of the variability in the physical tests. An equivalent study was performed using stochastic simulation with a metamodel fed with observed variability in impact conditions of physical headforms. An estimation of the test method uncertainty was obtained and used in the definition of a validation corridor for simulation models. Validation metric and criteria were defined in cooperation with the ISO TC22 SC10 and SC12 WG4 "Virtual Testing". A complete validation procedure including different test setups, physical magnitudes and evaluation criteria is provided. A detailed procedural flowchart is developed for VT implementation in EC Regulation No 78/2009 based on a so called "Hybrid VT" approach, which combines real hardware based head impact tests and simulations. This detailed flowchart is shown and explained within this paper. Another important point within the virtual testing based procedures is the documentation of relevant information resulting from the verification and validation process of the numerical models used. For this purpose report templates were developed within the project. The proposed procedure fixes minimum V&V requirements for numerical models to be confidently used within the type-approval process. It is not intended to be a thorough guide on how to build such reliable models. Different modeling methodologies are therefore possible, according to particular OEM know-how. These requirements respond to a balance amongst the type-approval stakeholders interests. A cost-benefit analysis, which was also performed within the IMVITER project, supports this approach, showing the conditions in which VT implementation is beneficial. Based on the experience gained in the project and the background of the experts involved an outlook is given as a roadmap of VT implementation, identifying the most important milestones to be reached along the way to a future vehicle type approval procedure supported by VT. The results presented in this paper show an important step addressing open questions and fostering the future acceptance of virtual testing in pedestrian protection type approval procedures.
Real world accident reconstruction with the Total Human Model for Safety (THUMS) in Pam-Crash
(2013)
Further improvement of vehicle safety needs detailed analysis of real world accidents. According to GIDAS (German In-Depth Accident Study) most car to car front accidents occur at mid-crash severity. In this range thoracic injuries already occur. In this study a real world frontal crash with mid-crash severity out of the AARU database was reconstructed. The selected car to car accident was reconstructed by AARU by means of pc-crash software in order to get the initial dynamic accident conditions. These initial conditions were used to reconstruct the complete accident in more detail using FE models for the car structure and the occupants. Occupant simulations were performed with FE HIII-dummy models and the THUMS using Pam-Crash code. An initial THUMS validation was performed in order to verify the model-´s biofidelity by means of table-top test simulations. THUMS bone stiffness values were modified to match the real word occupant age. A comparison between driver and passenger restraint system loading was done, as well as an injury prediction comparison between the HIII-dummy model and THUMS response for both cases. Detailed comparison between the HIII-dummy models and THUMS regarding thoracic loading are discussed.
Among European Countries, Spain first issued a Standard, UNE 135900:2005, further updated in 2008, that deals with homologation and effectiveness evaluation of road restraint systems components designed to reduce harm for bikers impacting on them. An in depth analysis and critical review of this standard is reported in this paper. Beside a close examination of the standard requirements, numerical models of the crash test stated by the standard have been set up and simulated to study the effects of slight speed and approach angle variations on test results, remaining within tolerance gaps allowed by the standard. Model were validated against experimental data. Together with the expected increasing severity of the impact according with speed, a strong influence of approach angle on injury parameters was found. Possible improvements to the norm, in order to make it more robust, are suggested.
Im Beitrag wird über Rissbildungen in orthotropen Fahrbahnplatten, die im "Schubzahn" des Querträgerstegblechs von den Anschlussschweissnähten trapezförmiger Längsträger ausgehen, berichtet. Der Rissausgangspunkt liegt im Bereich der Ausnehmung des Querträgersteges für die durchlaufenden Längsträger. Durch Optimierung der Querträgerausnehmung und örtliche Verstärkung (Aufpflasterung) des Querträgerstegblechs im Bereich des Schubzahnes soll eine dauerhafte Instandsetzung der aufgetretenen Schäden ermöglicht werden. Durch genauere numerische und versuchstechnische Untersuchungen soll diese Aussage untermauert werden. Einzelheiten der bereits durchgeführten Untersuchungen werden mitgeteilt.