Researchers at PNIPU studied how temperature affects the behavior of modern composites. The technology will strengthen the materials from which they create responsible structures for industry.
The study will be useful in the production of aircraft engines, engineering and the oil and gas industry, the developers say.
The results they published in the journals of the IOP Conference Series Materials Science and Engineering, Procedia Structural Integrity (1, 2) and Mechanics of Composite Materials (in print). The study was made possible thanks to a grant from the Russian Science Foundation.
- We have received new data on the patterns of deformation and fracture of composite materials. We studied their behavior in conditions that are close to operational and freelance. Composites are now widely used in critical structures in industry. Unlike classical metals, structures made of composites weigh less with the same volume; these materials are simpler and cheaper to produce. But their mechanical properties are not fully understood, and the accumulated knowledge and experimental data are not enough, ”says Dmitry Lobanov , senior researcher at the Center for Experimental Mechanics of PNIPU, candidate of technical sciences
To create products from polymer composites, it is necessary to analyze how they are affected by high and low temperatures. This is important for studying their mechanical properties and fracture mechanisms, scientists say. They paid special attention to how the strength and elasticity of materials change when exposed to temperatures. Measuring and testing equipment of the Center for Experimental Mechanics of PNIPU, which is included in the catalog of unique scientific facilities, helped researchers diagnose and control processes. This allowed scientists to conduct experiments and find out how temperature affects the behavior, strength and stiffness of polymer composites.
Scientists analyzed how damage accumulates in modern composite materials when exposed to temperatures. They identified methods by which experimental research is more efficient. To do this, they simultaneously used the ElectroPuls E test system 10000 and the AMSY-6 acoustic emission signal recording system.
The researchers conducted tensile and shear tests of the composite layers. To determine the strength and elasticity limits of carbon fiber reinforced plastic and fiberglass, they studied how normal (+ 22 º C) and increased (+ 10000 affect them º C) temperature. This made it possible to find out at what temperature the materials become less rigid and lose strength.
Using the equipment, scientists also obtained new data on the destruction of the composite, depending on the features of its structure and type of exposure. Researchers studied the microstructure of fiberglass and carbon fiber before and after the tests. They found that reducing the stiffness and volume of the material changes its “behavior” and affects the destruction. It also depends on the time of exposure to the material. The results recorded by the equipment and the microstructure data of the composite showed that temperature affects the mechanisms of its destruction.
Based on new data, scientists have developed recommendations that will help improve the structure of composite materials, effectively select their components and technological modes . This is important to improve production stability, mechanics say.