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A tomograph for scanning the interior of materials
EPFL has a unique tomograph in Switzerland. This camera delivers high-resolution images of the interior of a material. Designed for the engineering field, it can also be used in life sciences, archeology and art history.
How to see the inside of a piece of concrete without destroying it? Answer: by radiographing it. To do this, engineers use a tomograph, a kind of X-ray scanner that offers images that can reach up to a few microns for small objects. EPFL has just acquired a device of this type, which is unique in Switzerland.
A tomograph is like a medical scanner. It is however suitable for materials, not living organisms. Explanations of Pascal Turberg, scientific collaborator at the Institute of Civil Engineering and the Ecological Systems Laboratory: “Unlike the scanner in which the patient is stationary, the tomographer radiates an object that turns on itself. The device allows to collect several thousand images of a material and thus to reconstitute its internal structure in three dimensions, layer by layer, with great precision. ”
Observe the deformation of a material
On the scan of a cylinder of concrete, for example, multiple shades of gray appear in the image. The black spots show the natural porosity or the fractures of the material, the void, the clearest points, its aggregates and the intermediate tones, its cement. The heterogeneity, the quality and the imperfections of the interior of the material thus appear transparently.
The use of such images has many applications. For example, engineers will be able to perform “coupled experiments” to test the response of materials to various stresses: they can scan a metal, wood or concrete element, deform it, scan it again, and follow its Up to its fracturing. Observing the deformation of a live material is also possible. These images allow engineers to compare their theoretical numerical models with the actual observations made on the material.
At the EPFL, the potential for use of the tomograph is high. Several faculties are involved, notably ENAC, which is at the origin of the project and whose premises house equipment, engineering science and engineering (STI) and life sciences (SV). “The tomograph makes it possible to check the quality of a material and to control the manufacturing process, such as welding, in electronics. At the level of environmental sciences, one can imagine scanning rocks, plants, river sediments … The apparatus can also test the resistance of new composite materials intended for architecture or the manufacture of medical prostheses, “Says Pascal Turberg.
The latter also hopes to see flourishing collaborations outside the EPFL. According to the researcher, archaeologists, art historians and art restorers will also find an interest: “We have already had several contacts with people wishing to test the device. In its category, this instrument is the best on the market. It thus perfectly complements the other types of scanners we have access to for our research, notably those of the University Hospital Centers of Romandy and the Paul Scherrer Institute. What is innovative here is the combination of high resolution image rendering and a design that is suited to the research objectives of engineering. ”
source: The Ecole polytechnique fédérale de Lausanne (EPFL)