Smart materials could radically change the way we deal with infrastructure. Researchers are working on self-healing materials capable of automatically detecting damage they incur and repairing it without human intervention. Not only are such self-healing materials very practical, they can also save a lot of time and money.
The Western world is home to an enormous amount of infrastructure. This infrastructure wears out and needs to be maintained to keep it in good condition. This process is not only time-consuming and costly, but can also cause a lot of inconvenience. Think, for instance, of a motorway that has to be closed for repairs for some time due to (frost) damage, but also of a crack in a tunnel wall that has to be taken out of service as a result.
Self-healing materials
University College London (UCL) professor Mark Miodownik points out that many objects today are simply replaced as soon as they fail, as repair is too complex. Infrastructure is currently still repaired, but even this process is becoming increasingly difficult and expensive, according to Miodownik. Some people therefore advocate making materials less complex, so that they can be repaired more easily and need to be replaced less quickly.
However, Miodownik is not a proponent of this approach and instead wants to make materials much more complex so that they are able to independently detect damage incurred and repair this damage autonomously. UCL is working with the University of Leeds on such self-healing materials, for which the 'Self-Repairing Cities' project has been set up.
Automatically repair cracks in aircraft fuselages
An article published by Miodownik on FT.com cites several examples of such self-repairing materials. For example, Miodownik points out that the aviation industry has been working for some time on self-healing materials to allow microscopic cracks in aircraft fuselages to be repaired automatically. This not only increases aircraft safety, but also extends the life of the aircraft and thereby reduces costs.
The aerospace industry is using a technique inspired by the human body's clotting mechanism to do this. The material incorporates microcapsules containing a liquid resin. If a crack occurs in the material, these microcapsules tear open and the liquid resin is released. This resin comes into contact with the fibres of the composite material and is activated by a catalyst, causing the material to harden and repair the crack.
What has the Self-Repairing Cities project achieved so far?
In a report on the Self-Repairing Cities project released this week, the universities set out the project's progress. In doing so, several successes of the project are discussed. These include the development of:
- a pipe inspection robot that can operate autonomously in pipes about 2.5 centimetres in diameter. The robot is charged wirelessly, allowing it to operate in pipes for longer periods of time;
- a drone using an integrated 3D printer that can repair cracks and holes in roads using polymer. In addition, the 3D printer can print a form of asphalt that researchers say performs better than traditional asphalt;
- a drone system that can monitor and coordinate the movements of trucks on construction sites;
- a drone that can autonomously land on a street light and perform maintenance work using a robotic arm;
- a trial to assess the ecological impact of robots on their natural environment;
- a simulation how simple and inexpensive 'roadside robots' can be used to detect wear and tear on roads. The system is controlled using a management system based on the brains of nematodes (worms). Detected damage can then be repaired by the aforementioned drone with built-in 3D printer.
More information about the project can be found on the self-repairingcities.com website and in the progress report released by the University of Leeds and UCL.
Author: Wouter Hoeffnagel
Source: University of Leeds
Source: University College London
Source: Self-Repairing Cities project
Source photo: Pixabay / Kasman
