PSI - Issue 30

A.K. Kychkin et al. / Procedia Structural Integrity 30 (2020) 173–178 Kychkin A.K., Struchkov N.F., Vinokurov G.G. et al. / Structural Integrity Procedia 00 (2020) 000–000

174

2

1. Introduction With the development of the Arctic and Subarctic, studies of the influence of long-term extreme climatic conditions on the properties of polymer composite materials (PCM) become relevant. Along with traditional fiberglass, aramid, carbon-reinforced polymeric materials, one of the promising materials is PCM based on continuous basalt fiber. According to the proposed certification program by Ruzek R., et al. (2009), to substantiate the terms of safe operation of PCM in industry, climatic qualification is carried out by monitoring a complex of physical and mechanical properties for long periods of operation.

Nomenclature P о

average porosity

n S

concentration of reinforcing roving fibers

cross-sectional area

D d 0

diameter of the cross-section of the basalt fiber reinforced polymer

depth of the outer layer subject to degradation The review and analysis of known studies carried out by Panin et al. (2014) and by Slavin et al. (2018) was show, that under the influence of ultraviolet solar radiation and humidity at the initial stage of climatic aging, the structure of the surface layers of PCM deteriorates with the formation of microcracks. As a result, with seasonal and daily temperature drops from 0°C, the appearance of microcracks and the formation of volumetric microdamages is accelerated, that leads to a significant deterioration in the mechanical parameters of PCM according to observation did by Li et al. (2012) and Dutta (1988). Changes in the mechanical parameters of carbon fiber reinforced plastic, organoplastic and fiberglass were investigated by Bulmanis et al. (1991) depending on the nature of the reinforcement. It has been established that over three years of natural impact in a cold climate there are significant changes in the strength indicators of fiberglass and carbon fiber reinforced plastics. For organoplastics, there is a more significant deterioration in the mechanical properties of samples exposed on open stands than in an unheated warehouse, where there is no ultraviolet radiation. Changes in the physical and mechanical parameters of PCM are studied by Andreeva et al. (2019), Babenko et al. (2006), Kablov et al. (2013), Startsev et al. (2018), so the general kinetics of a decrease in strength and thermophysical parameters during exposure in the climatic conditions of the North is revealed. Therefore, the study of the influence of climatic conditions on the performance characteristics of PCM is an urgent task for the creation of new materials and technologies for their creation based on PCM. The aim of this work is to study the formation of microdamages and porosity of basalt fiber reinforced polymer in extreme climatic conditions of the North. 2. Materials and Methods The objects for experimental research in this work are basalt-plastic composite materials for structural purposes - unidirectional basalt fiber reinforced polymer rebars based on epoxy resin with diameters of 6, 8 and 20 mm. basalt fiber reinforced polymer were subjected to climatic tests by exposure for 51 months at the open range of the Larionov Institute of Physical and Technical Problems of the North SB RAS in natural climatic conditions of Yakutsk. For comparison, the basalt fiber reinforced polymer rebars from the same production batch, warehouse storage under normal conditions were selected as raw materials Determination of open porosity was carried out by the method of hydrostatic weighing. To measure the open porosity of basalt fiber reinforced polymers by cutting along the cross-sections, samples were made in the form of cylinders with a length of ≈ 30 mm. Kerosene was used as a working impregnating liquid; weighing was carried out on electronic scales with an accuracy of 0.0001 g.