TOMSK, Jan 30 – RIA Tomsk. Scientists of Tomsk Polytechnic University (TPU) with colleagues from Malaysia for the first time investigated the carbon-carbon composite using a new method – ultrasound infrared thermography. This allow to find defects in external parts of missiles and airplanes online with high accuracy, the press service of the university reported on Wednesday.
It is specified that composite materials are widely used in aerospace engineering, shipbuilding and automotive industry due to their high strength with relatively low mass and resistance to corrosion. However, composites are vulnerable to external damage, for example, at a hail, collisions with birds, blows with tools. Defects in such materials are often invisible and fraught with danger.
Polytechnicians suggested a research associate of Malaysian Nuclear Agency Mohd Zaki Umar, who had an internship at the university, to use ultrasonic infrared thermography method to control the carbon-carbon composite, becose it combines two approaches: ultrasonic and thermal. The method has not yet been implemented in the Russian Federation, but has several advantages.
"The essence of the method is simple: into the test object powerful introduced ultrasound with a frequency of 20–40 kilohertz – much more powerful than in traditional ultrasound testing. An ultrasonic wave propagating in a solid causes friction of the walls of defects, generating thermal energy. We fix this energy using infrared cameras ... According to the thermal "print" of defects, one can judge their location and characteristics", – the head of the "Thermal Control" laboratory Vladimir Vavilov is quoted.
It is noted that as a result of experiments, the method proved to be very effective for detecting damage in the carbon-carbon composite, in particular, so-called "kissing" defects – for example, cracks, the edges of which are in close contact with each other and which are difficult to detect with standard ultrasound and x-ray methods.It is added that TPU – is one of the few research centers in the Russian Federation where studies in the field of ultrasonic infrared thermography are conducted. The research results are published in the Composites Part B: Engineering journal.