Particular emphasis is being placed on rail vehicles where, on the one hand, improved crash safety is being demanded and, on the other hand, only a limited number of real crash tests can be performed due to the high costs involved. Simulation models are to allow an improved assessment of the failure of welds in the future.
At present, crash tests represent the state of the art not only in the automobile industry but also in the rail vehicle sector. In the course of a cooperative project with Siemens Transportation Systems TU researchers investigated the strength of weld seams in rail vehicles under crash loading as part of a research project funded by the city of Vienna (ZIT). “During collisions not only individual structural components but also the joints between them are exposed to enormous loads. Spot welds play an important role in the crash behaviour of motor vehicles, whereas rail vehicles tend to employ continuous weld seams. Both can be critical in the event of a collision”, notes Helmut Böhm, Head of the Institute of Lightweight Design and Structural Biomechanics of Vienna University of Technology (TU).
The reason why welded joints may be subject to failure lies in the thermal conditions they are subjected to during welding. The metal is heated and molten, which can significantly modify its properties. With the aid of computer simulations professor Böhm and project assistant Christian Grohs studied the inhomogeneous and heat affected material involved in weld seams. “The objective is to enable the structure to absorb as much kinetic energy as possible during a crash. It is constructed in such a way that it can be severely deformed, e.g. by developing patterns of folds. This reduces the risk of injury for passengers”, says Helmut Böhm. Christian Grohs adds: “An extensive experimental test programme, which forms the basis for numerical analysis, was defined and carried out in cooperation with the Institute of Materials Sciences and Technology. We can then recheck the test results and construct better models using this data. The test structure was defined in such a way that the weld seams are located at the most unfavourable positions with the aim of inducing them to fail during the test. The models, in turn, serve to improve the design of rail vehicles”.
A new standard on the collision safety of rail vehicles is to be introduced in 2008. Since crash tests of rail vehicles are very expensive, simulations play a major role in verifying their crash behaviour. Such work must demonstrate that gross deformations of rail vehicles are restricted to so-called crash zones which are situated in regions where there are no people. Dr. Seitzberger, crash expert at Siemens Transportation Systems, states: “An intensive basic research-oriented debate on the issue of the passive safety must be regarded as essential for successfully carrying out future projects. The present cooperation represents a significant contribution to the continued development of know-how and competence in this field and will contribute to enhancing the safety of modern rail vehicles”.
Daniela Hallegger | alfa
New players, standardization and digitalization for more rail freight transport
16.07.2018 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
A helping (Sens)Hand
11.04.2018 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO
Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.
Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
20.11.2018 | Life Sciences
20.11.2018 | Life Sciences
20.11.2018 | Physics and Astronomy