MIT civil engineers and University of Potsdam researchers have developed a new method for the continuous electronic monitoring of structures using a flexible skin-like fabric with electrical properties. When adhered to areas of structures where cracks are likely to appear, the material can detect cracks when they occur. This skin could be glued to a structure’s surface in precisely the size required. Different arrangements of patches could be used for detecting specific potential causes of failure. Those placed in a diagonal, for example, would best detect shearing while horizontally-oriented patches might best detect the cracks caused by a sagging horizontal beam. Any movement in the concrete under the patch would change the skin’s capacitance, enabling engineers to detect the precise location of the problem. Most existing approaches detect global structural changes using a few strategically placed sensors. “Such automation in the [structural] health monitoring process could result in great cost savings and more sustainable infrastructures, as their lifespan would be significantly increased as a result of timely repairs and reduced number of inspections,” said Simon Laflamme, project researcher. Researchers say the monitoring technology would greatly help the aging US civil infrastructure, namely bridges, dams, and schools. Since initially testing the concept with commercially available stretchy silicon fabric with silver electrodes, the researchers developed a prototype skin from thermoplastic elastomer mixed with titanium dioxide. Painted patches of black carbon measure the change in the skin’s electrical charge. The researchers have applied for a patent on the method. (PhysOrg.com)(MIT)
