Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

‘Sensing skin’ could monitor the health of concrete infrastructure continually and inexpensively

30.06.2011
In 2009, the American Society of Civil Engineers (ASCE) assigned the grade “D” to the overall quality of infrastructure in the U.S. and said that ongoing evaluation and maintenance of structures was one of five key areas necessary for improving that grade.

Since that time, federal stimulus funds have made it possible for communities to repair some infrastructure, but the field of high-tech, affordable methods for the continual monitoring of structures remains in its infancy. Instead, most evaluation of bridges, dams, schools and other structures is still done by visual inspection, which is slow, expensive, cumbersome and in some cases, dangerous.

Civil engineers at MIT working with physicists at the University of Potsdam in Germany recently proposed a new method for the electronic, continual monitoring of structures. In papers appearing in Structural Control Health Monitoring (December 2010) and the Journal of Materials Chemistry (April 2011) the researchers describe how a flexible skin-like fabric with electrical properties could be adhered to areas of structures where cracks are likely to appear, such as the underside of a bridge, and detect cracks when they occur.

Installing this “sensing skin” would be as simple as gluing it to the surface of a structure in the length and width required. The rectangular patches in the skin could be prepared in a matrix appropriate for detecting the type of crack likely to form in a particular part of a structure. A sensing skin formed of diagonal square patches (3.25 inches by 3.25 inches, for instance) would be best at detecting cracks caused by shear, the movement in different directions of stacked layers. Horizontal patches would best detect the cracks caused when a horizontal beam sags. The largest patch tested using the prototype reached up to 8 inches by 4 inches in size.

The formation of a crack would cause a tiny movement in the concrete under the patch, which would cause a change in the capacitance (the energy it is storing) of the sensing skin. Once daily, a computer system attached to the sensing skin would send a current to measure the capacitance of each patch and detect any difference among neighboring patches. In this way, it would detect the flaw within 24 hours and know its exact location, a task that has proved difficult for other types of sensors proposed or already in use, which tend to rely on detecting global changes in the entire structure using a few strategically placed sensors.

“The sensing skin has the remarkable advantage of being able to both sense a change in the general performance of the structure and also know the damage location at a pre-defined level of precision,” said Simon Laflamme Ph.D. ’11, who did this research as a graduate student in the MIT Department of Civil and Environmental Engineering (CEE). “Such automation in the 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.” Laflamme, worked with Professor Jerome Connor of MIT CEE and University of Potsdam researcher Guggi Kofod and graduate student Matthias Kollosche.

The researchers originally tested their idea using a commercially available, inexpensive stretchy silicon fabric with silver electrodes. While this worked in some of the lab experiments performed on both small and large concrete beams under stress, the material showed limitations in its installation because it was too thin and flexible for this use. The researchers have now developed a prototype of a sensing skin made of soft stretchy thermoplastic elastomer mixed with titanium dioxide that is highly sensitive to cracks, with painted patches of black carbon that measure the change in the electrical charge of the skin. A patent for the sensing method was filed in March 2010.

“Many of the types of infrastructures graded by the ASCE are made of concrete and could benefit from a new monitoring system like the sensing skin, including bridges which received a C grade, and dams and schools, which earned Ds,” said Connor. “The safety of civil infrastructures would be greatly improved by having more detailed real-time information on structural health.”

The work of Kofod and Kollosche was funded by the German Ministry of Education and Research.

Denise Brehm | EurekAlert!
Further information:
http://www.mit.edu

More articles from Life Sciences:

nachricht Flow of cerebrospinal fluid regulates neural stem cell division
22.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Chemists at FAU successfully demonstrate imine hydrogenation with inexpensive main group metal
22.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>