TOMSK, May 11 – RIA Tomsk. Scientists of Tomsk Polytechnic University (TPU) together with foreign colleagues research composite materials from organic fibers based on sugar cane. Task of the team – is to find the best method for detecting defects in composites, allowing use these materials in construction and other industries. In more detail – in the material of RIA Tomsk.
As reported in the TPU newspaper "For personnel" polytechnicians and their colleagues – scientists from Italy, Canada and Germany participate in the project. They study the thermophysical characteristics of samples of new composites from sugarcane oilcake.
Composite samples were manufactured at the University of L'Aquila (Italy). These materials, according to scientists, can be successfully used for thermal insulation of building structures in countries with hot climates, as well as for the manufacture of furniture.
"The development of composite materials from organic fibers based on sugar cane – is a relatively new direction. There is a certain problem of controlling their quality: traditional methods – X-ray and ultrasound – do not fit", – words of the research associate of the Research School of High-Energy Physics Arseny Chulkov are cited in the newspaper.
He explains: during transportation or installation panel from composites can be damaged, and in most cases such defects with the naked eye cannot be identified.
© Валерий Доронин
To find the best method of detecting damage, scientists conducted a series of experiments. To study defects, four samples of composites were subjected to impact damage with an impact energy ranging from five to 30 joules (J). Then the nature of the damage was evaluated by both polytechnicians and their foreign counterparts.
"In TPU thermophysical characteristics of composite materials were studied using active infrared thermography. Foreign colleagues, in turn, used radiation in the terahertz range with a wavelength of 0.1 to 1 millimeter. Such radiation, passing through the material of the samples, in defective and defect-free areas weakens in different ways", – says Chulkov.
The data obtained by the two groups were combined. As a result, both methods of defect control - active infrared thermography and terahertz imaging – gave good results. They made it possible to determine the size of impact damage zones, the depth of delamination in the material, and the thermal diffusivity (a parameter that determines the rate of heat propagation in the medium).
"In samples in which the impact is stronger, thermal diffusivity is lower. In other words, the rate of heat propagation in defective structures due to the fact that there are stratifications is lower. This is a good parameter to evaluate the structure of the material depending on the degree of its defectiveness", – explains polytechnician.
Within the framework of the project, the international team of scientists published in the Infrared Physics and Technology journal an article entitled "Determining the thermophysical characteristics of composite samples from sugar cane using active thermal control and terahertz visualization".
Scientists believe that the production technology of chipboard panels, which include sugarcane cake, will help reduce the use of wood and reduce the environmental burden on forests.