VEHICLES and buildings could soon tell us when they鈥檙e feeling sick thanks to
a coating that monitors their health. 杏吧原创s in Japan have developed a paint
that senses the vibrations that warn of structural damage.
Shigenori Egusa at the Japanese Atomic Energy Research Institute and his
colleagues from the Kansai Paint Company in Japan made the coating by mixing
epoxy resin with powdered lead zirconate titanate, a piezoelectric ceramic. The
sticky resin mixture is painted onto a surface and left to dry.
If a surface coated with the mixture begins to vibrate, the resin layer
flexes, squeezing the particles of lead zirconate titanate. Each particle then
generates a tiny electrical signal that can be picked up by thin metal
electrodes placed on either side of the resin layer. Areas that vibrate the most
give the largest electrical signals.
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In their experiments, Egusa and his team found that squares of paint 5
centimetres across on an aluminium beam can successfully map the beam鈥檚
vibrations between frequencies of 0 and 250 hertz (Journal of Smart
Materials and Structures, vol 7, p 438).
Egusa believes that similar patches on vehicles, building supports and plane
wings could give an early warning of structural failure. 鈥淧otentially, the paint
can be applied to all kinds of metals, ceramics and concrete,鈥� says Egusa.
鈥淪mart paints that respond to their environment are part of the future,鈥� says
Geoffrey Tomlinson, a mechanical engineer at the University of Sheffield.
鈥淎ssuming that they are robust and that the signal output can be optimised,
piezopaints offer an interesting and promising alternative to classical
蝉别苍蝉辞谤蝉.鈥�