Researchers from Trinity College Dublin's School of Engineering believe that bamboo could be used to build many things from bicycles to houses in the not-too-distant future.
Bamboo has long been used in Asia for everything from buildings to chopsticks but there is now an increasing interest in Europe to exploit it as a replacement for traditional structural materials. Because it is stiff, strong and grows very rapidly, the engineers say it can be ‘a key’ sustainable resource as it can substitute for more limited resources like hardwood, metal ores and petroleum products.
To test its suitability, the engineers performed a detailed ‘fatigue failure’ analysis to see whether they could accurately assess bamboo’s strength and durability, and predict the point at which it might fail due to physical stress or wear and tear.
“Fatigue is the most common cause of failure in engineering structures, being responsible for about 70% of all mechanical failures. Metal fatigue is a big problem in aircraft, for example, but we also know that other materials such as plastics and ceramics can suffer from fatigue,” said Professor of Materials Engineering at Trinity College Dublin, David Taylor, who led the study.
Fatigue failure occurs gradually if a material is repeatedly stressed. To see fatigue happening all you have to do is take a paper clip and bend it. It doesn’t break the first time, but if you bend it backwards and forwards a few times it will eventually break.
It turns out that bamboo is very strong when tested along its length, parallel to the growing stem, which is called a ‘culm’. In this direction it doesn’t suffer from fatigue at all, which is very useful to know from a constructor’s perspective. Although it is much weaker when loaded across the diameter of the culm, where it splits easily, and suffers from fatigue, the limits can be accurately predicted.
Professor Taylor added: “Sometimes fatigue can happen after millions of repetitions, so it could be very important in, for example, a structural member in a building, or in a bicycle. But knowing the limits means we could use this sustainable resource for any number of applications, such as people’s homes or turbine blades, which is very exciting.”
The work has recently been published in the peer-reviewed International Journal of Fatigue. The paper can be downloaded free of charge for a limited period, until 10th April, from the following link: http://authors.elsevier.com/a/1QZhnWK0Q3SO8