New Aluminium Foam promises faster, stronger and lighter trains
The material consists of a 25 mm thick layer of the “foam,” actually a low-density, sponge-like composite of magnesium, silicon, and copper, and aluminum, which is sandwiched by two 2 mm thick aluminium sheets. There is no glue either, it’s all held together by metallic bonds.
The foam results in a material that is 20 percent lighter than traditional fiberglass, the material commonly used these days for train cabs. Of course, this is beneficial for both improved speeds and efficiency.
“The outer shell is so stiff that you need no ribs inside,” says Dr. Thomas Hipke, head of lightweight construction at the Fraunhofer Institute for Machine Tools and Forming Technology, which helped to design the prototype train cab.
To test the material the team performed experiments where they applied force to try to rip the layers apart but the foamy filling stretches rather than the bonds between the layers breaking. This is a great demonstration of strength and its ability to absorb an impact too.
“Aluminum foam has a very high and comfortable impact resistance, especially for small impacts like stones, bottles or just birds,” says Ralf Uhlig of Voith Engineering Services, which was involved in the construction of the prototype cab.
The technology is not new either; Aluminium foam was conceived back in the 1960s but was far too expensive to be manufactured and shaped for use. Now, engineers at the Fraunhofer Institute and Voith Engineering Services have demonstrated aluminum foam surfaces can be formed economically using embossing tools: The contours of the material are set during the foaming process, rather than conventionally stretching the material around a blank of the desired shape.
“We save approximately 60 percent on tool costs,” says Dr. Hipke.
So, maybe sometime soon we can start catching up with Asia’s train tech.
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