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Background Cervical disc prostheses are used to preserve motion after discectomy, but they should also provide a near-physiological qualitative motion pattern. Nevertheless, they come in many completely different biomechanical concepts. This caused us to perform an in-vivo MR-based biomechanical study to further investigate cervical spine motion with the aim to gain new information for improving the design of future cervical arthroplasty devices. Methods Fifteen healthy volunteers underwent MRI-investigation (in order to avoid radiation exposure) of their cervical spines from C3 to C7; for each segment centers of rotation (COR) for flexion / extension were determined from 5 different positions, and CORs for lateral bending from 3 different positions. The motion path of the COR is then described and illustrated in relation to the respective COR for maximum flexion / extension or lateral bending, respectively, and the findings are translated into implications for a better biomechanical prosthesis-design. Results The COR for flexion / extension does not remain constant during motion. The CORs for the respective motion intervals were always found at different positions than the COR for maximum flexion /extension showing that the COR moves both along the x- and the y-axis throughout flexion / extension. For lateral bending a completely independent COR was found above disc-level. Conclusion Flexion / extension is not a simple circular motion. Disc prostheses need a variable COR for flexion / extension below disc level with the capability to move both along the x- and the y-axis during motion, plus a second completely independent COR for lateral bending above disc level to closely replicate in-vivo motion. These findings are important for improving the biomechanical design of such devices in the future.

Lithium-ion batteries are in widespread use in electric vehicles and hybrid vehicles. Besides features like energy density, cost, lifetime, and recyclability the safety of a battery system is of prime importance. The separator material impacts all these properties and requires therefore an informed selection. The interplay between the mechanical and electrochemical properties as key selection criteria is investigated. Mechanical properties were investigated using tensile and puncture penetration tests at abuse relevant conditions. To investigate the electrochemical performance in terms of effective conductivity a method based on impedance spectroscopy was introduced. This methodology is applied to evaluate ten commercial separators which allows for a trade-off analysis of mechanical versus electrochemical performance. Based on the results, and in combination with other factors, this offers an effective approach to select suitable separators for automotive applications.

This industrial project introduces an ultraflat automated robot that can be used for testing driver assistance systems as well as automated driving scenarios. Because of its very stable and flat structure, it can be overrun by test vehicles without any damage. Therefore, it is possible to use this robot for both pre- and postcrash testing scenarios as well as for the evaluation of active safety systems (e.g., automatic brake) and autonomous driving.

The objective of this work is to test freely available system for active pedestrian protection. Tests are based on real fatal accidents that happened in the past with passenger cars that were not equipped with active safety systems. Tests have been conducted in order to evaluate what the real benefit of the active safety system is, and not to gain only a methodological prediction. The testing procedure was the first independent testing in the world which was based on real fatal pedestrian accidents. The aim of the tests is to evaluate the effectiveness of Volvo pedestrian detection system. An in-depth accident database contains about 300 fatal pedestrian traffic accidents in urban areas. Eighteen cases of pedestrians hit by the front end of the passenger vehicle were extracted from this database. Cases covering an average traffic scenario have been reconstructed to obtain detailed model situations for testing. Simulations of accidents have been made in PC Crash 10.0 using a multibody object and a mesh model of vehicles. Active safety testing scenario was built on the basis of reconstructed accidents with Volvo V40 cc and a new dummy simulating a pedestrian. Before the tests the dummy was evaluated in anechoic room to gain required radar reflection properties which would be the same as those of a human body. The movement of the dummy was driven by the autonomous ultraflat overrunable robot (UFO) for experimental advanced driver assistance systems (ADAS) testing and synchronized with Volvo motion by global positioning system (D-GPS) with high accuracy of motion.

In der Retrospective Case Study der Technischen Universitaet Graz (RCS-TUG-Studie) wurde eine Potenzialanalyse fuer Systeme der aktiven Sicherheit und Fahrerassistenz mithilfe einer numerischen Simulation der Vorkollisionsphase von realen Unfaellen durchgefuehrt. Die Besonderheit der Untersuchung liegt in der Rekonstruktion der Vorkollisionsphase aus einer In-Depth-Unfalldatenbank. Es wurden 43 Systeme in 217 Faellen analysiert. Die wirksamsten Systeme wurden qualitativ beschrieben und fuer unterschiedliche Fahrzeugkategorien bewertet. Kombinationen von isoliert betrachtet besonders wirksamen Systemen lassen sehr hohes Potenzial zur Vermeidung von toedlichen Verkehrsunfaellen erwarten. Besonders wirksam sind die Systeme Ausweichassistent, Spurhalteassistent, Notbremsassistent, Elektronische Stabilitaetskontrolle, Kollisionswarnsystem und Aufmerksamkeitsassistent. Eine vollstaendige Marktdurchdringung der Fahrzeugflotte mit einer technologisch einwandfreien Funktion der Kombination der Systeme ABS, ESC, Notbremsassistent und Spurhalteassistent laesst eine theoretische Reduktion der toedlichen Unfaelle im Bereich von 42 bis 62 Prozent erwarten. Die Studie soll als Entscheidungshilfe fuer Hersteller, Institutionen und den Endkunden dienen, um eine Orientierung in der Vielfalt heutiger Systeme der Fahrerassistenz und Fahrdynamikregelung zu geben und als Moeglichkeit zur Priorisierung fuer Einfuehrungsszenarien in der Fahrzeugflotte dienen.

While reconstructing a car accident, there are several questions that must be answered, such as the movement of all the vehicles involved or of other people involved, or of objects from the point of first visual contact to their rest positions. Time history of velocities, positions as well as crash-related data such as velocity changes, deformation energies, or passenger loads must also be analysed. Methods to aid in accident reconstruction combine the simulation of pre-collision, collision, and post-collision dynamics for multiple vehicles. This paper presents trajectory and collision models used for accident reconstruction as well as useful optimisation strategies. The model for predicting the 3D kinematics of a vehicle's pre- and post-impact trajectory, which is based on a discrete kinetic time forward simulation of vehicle dynamics, has been described. The tyre model, steer angle, wheel braking, weight shift, and suspension effects have been introduced and a method of handling pre-impact yaw, braking,...

This article investigates the current accident statistics using data provided by GIDAS and Austrian databases. It shows that among frontal crashes between cars, the impact configuration with small lateral overlap (

Understanding human head kinematics prior to the safety countermeasure activation is important to help minimize potential for injury in side impact and rollover situations. The objective of this study was to compare three volunteers and the Hybrid III responses in three low-to-moderate lateral crash pulses. The parameters evaluated were lateral pulses and belt usage. A total of 24 tests were carried out in a side impact sled. The subjects consisted of two 50th percentile males (Volunteers 1 and 2), one 5th percentile female (Volunteer 3) and a Hybrid III 50th percentile male. All subjects were in near-side impacts. The pulses consisted of two 4 g pulses (6 and 8 kph) and a 4 g/8 kph followed by a m 2.5 g pulse to simulate a low curb impact. In the 6 and 8 kph pulses, the antropometric test devices' head trajectory is somewhat similar to the volunteers'. For near-sided/belted occupants, the peak lateral excursion was 327 - 53 mm for the volunteers, and 269 mm for the Hybrid III in the 6 kph pulse, while it...

Road accidents involving large animals are responsible for a considerable number of fatalities; these are e.g. elk in Northern Europe or camels in Middle East, Horn of Africa and Maghreb. In order to address this topic, investigations concerning active and passive road safety have been launched at the King Saud University and at Graz University of Technology. Data of real accidents or accident statistics are not available in the required quality to gather typical accident scenarios. Therefore generic accidents types were derived and critical load cases were determined by means of multi body and finite element simulations. It was found that the vehicle acceleration due to the impact is not a safety issue, but the finite element simulations showed that massive local intrusions into the passenger compartment are the main cause for severe occupant injuries. Therefore, concepts for the prevention of critical intrusions were examined. In a first step the space required for the occupant movement due to the rather mediocre acceleration levels in car-to-large animal accidents was determined by multi-body simulation. In a second step different approaches preventing intrusions into the occupant-movement-space were analyzed by finite element simulation. In addition, the possible effects and requirements of active systems have been studied to demonstrate the potential of combined measures.

Within the scope of developing a multi-physical model describing battery behavior during and after the mechanical load (accelerations, intrusions) of a vehicle’s high voltage battery, an internal short circuit model is of deep interest for a virtual hazard assessment. The internal short resistance and the size of the affected area must be known as a minimum for determining the released heat and, in consequence, the temperatures. The internal short resistance of purpose-built dummy pouch cells, filled with electrolyte-like solvent without conductive salt, has thus been measured in a given short area under various compressive loads. The resistances for different short scenarios obtained are analyzed and described in a mathematical form. Short circuit experiments with dummy cells using an external power source have also been carried out. This set-up allows the measurement of the temperature evolution at a known current and a determination of the actual short resistance. The post-mortem analysis of the samples shows a correlation between the maximum temperatures, released short heat and the separator melt diameter.

IntroductionAn in-vivo biomechanical study is presented investigating the Center of Rotation (COR) for flexion/extension before and after insertion of 3 different types of cervical disc prostheses. The aim of the study was to investigate whether the pre-operative coordinates of the COR deviate from that of Healthy Volunteers (COR-HV), and further whether and how the COR-coordinates change after insertion of the different disc prostheses.Material and Methods15 healthy volunteers underwent MRI-investigation of their cervical spines. Data for flexion/extension were collected in 5 different positions from maximum extension to maximum flexion for determination of the COR-HV. Further, from 30 patients with a one-level cervical disc prosthesis (10 respective patients who received a Bryan-, Discover- or Prestige-prosthesis) the routinely taken pre- and post-operative cervical flexion/extension X-rays underwent graphical analysis for determination of the respective COR from C3/4 to C6/7. The pre- and post-operativ...

Although accidents with animals represent a small portion in the official statistics, these accidents have an economic effect. The regulatory costs in Germany added up to an average of 370–464 million Euros annually in the years between 2000 and 2005. The insurance companies registered between 210,000 and 235,000 deer accidents on average every year. The largest part of the data collected by the insurance companies is accidents with damage to property. But accidents with large animals are a danger to vehicle occupants. German statistics for accidents with animals for this period show between 18 and 28 fatally injured persons and between 580 and 750 severely injured and 2,100–2,600 light casualties every year. Accidents that are caused by evasive maneuvers causing running-off track and finally colliding with the infrastructure or causing a cross-over collision have not been taken into account. The aim of this investigation is to evaluate typical accident scenarios and accident simulation with large animals. In particular, the effects on the vehicle occupants are investigated by multi-body simulation methods. The occupant load for accidents with animals is determined and influencing factors on the load are derived. Based on these investigations, avoidability scenarios are developed and methods are introduced that are relevant to the vehicle (active and passive safety) and also to the infrastructure and the driver. The objective is to develop effective counteractions in order to avoid accidents with animals or at least mitigate the accident aftermath.

In zunehmendem Mase werden bei der Rekonstruktion und Analyse von Strasenverkehrsunfallen komplexe Rechenprogramme eingesetzt. Damit in Verbindung stehen neue Fachbegriffe und Verstandigungsprobleme zwischen den Experten und den Empfangern von Gutachten.

The aim of this study was to assess the feasibility of using a high speed x-ray system (capable of 1000 frames/sec) to evaluate the bony kinematics of post mortem human surrogate (PMHS) cervical spines at real world speeds during frontal impact. Whole body frontal impact sled tests were performed on two fresh PMHS specimens. Screws were inserted into the tips of the spinal processes to optimize contrast on the high speed cine x-ray. Head, T1 and sternum accelerations, as well as shoulder, and lap belt forces were recorded. Vertebral motion was captured using a modified mobile c arm x-ray system, and an image intensifier linked to a high speed camera (Kodak motion corder analyzer, model SR 1000C, Kodak, San Diego, CA, USA) The variable parameters for the tests were camera frame rate and sled velocity. Tests were performed with delta-V's (Av) of approximately 15 kph (8G) and 21 kph (10G). Cine x-rays of the tests were recorded at 250, 500 and 1000 frames /sec. Motion tracking analysis of the bony elements of the cervical spine was performed. Only tests recorded a 250 frames/sec produced high enough quality images to perform motion analysis. The results show high speed cine x-ray can be used to directly visualize the bony skeleton, for the assessment of skeletal kinematics during impact. Analysis of bony kinematics using high speed cine x-ray reduces errors caused by extrapolating data from external surface makers. Additionally, the system also offers the potential for detecting the site at which fractures originate. It also allows visualization of the timing of fractures, and the order they occur in. Further research and testing is required to optimize the use of the system, to increase the field of view and improve image quality at the highest frame rates (> 500 frames / sec).

The pedestrian model in PC-Crash is based on a multi-body system, where several bodies are interconnected by joints. This paper describes in detail the validation process for the pedestrian model. A significant number of crash tests (approx 30) was used as a basis to compare the results of the simulations and the real movement of the test subjects. Different test configurations were selected to provide a set of crash tests, which represents real cases as close as possible. To show the difference between dummy movement and the movement of human test subjects some tests with human test subjects and some real cases, which were very well documented, have been used. Each of the different tests was reconstructed using PC-Crash and the pedestrian model and the significant difference between simulation results and crash tests are pointed out. A special interest has been focused on the pedestrian trajectories and the contact locations between the pedestrian and other objects. All tests and simulations are compared in the conclusion and the usability of the pedestrian model in different accident configuration is discussed. Typical parameter ranges for the different input parameters like pedestrian geometry, weight and stiffness parameters are presented as well. (A) For the covering abstract see ITRD E106540.

The aim of this study is to validate the pressure effect theory on human beings during a realistic rear-end impact and to correlate the neck injury criterion to pressure in the spinal canal. Sled experiments were performed using a test setup similar to real rear-end collisions. Test conditions were chosen based on accident statistics and recordings of real accidents. In particular, velocity change and acceleration level were reproduced similar to actual collisions. The head restraint as well as the seat back were adjusted to different positions. Two small pressure transducer were implemented to the spinal canal of postmortem human subjects and pressure measurement similar to the pig experiments (using exactly the same equipment) were performed. A total set of 21 experiments with four different subjects were performed. The subjects were additionally instrumented with triaxial accelerometers that allowed for calculation of the NIC criterion. Results showed that NIC and pressure amplitudes of the CSF correlate well and therefore NIC seems to be able to predict these amplitudes also for human beings. Conclusions whether these pressure effects induce soft tissue neck injuries or not could not be drawn and should be investigated in further research.