The study of the rheological properties of composite materials of power elements of building structures

Abstract

The dependences of residual strains on the residence time of the polymer composite material in various media are presented. Samples were taken in the form of flat long elements reinforced with fibreglass. The studied samples were deformed in the form of a three-hinged fastening, by analogy with the longitudinal bending method, mechanical deformation was assumed to be 20, 30, and 60 % of the destructive deformation. When conducting intermediate measurements, the equipment was disassembled and, after performing control measurements, reassembled. Test temperature accepted 18 ± 3 degrees. Samples were aged in selected media for 540 days with intermediate measurements. Relations are proposed for determining the residual strength, the parameters of which can be obtained on the basis of experimental data on three-point bending. A multifilament high-strength polyethylene fibre with the number of filaments in a multifilament bundle of 900 pieces and a filament diameter of 17 mkm was investigated. The tests were carried out under uniaxial tension with different temperatures and stresses. The method of minimizing the quadratic residual was used according to the results of a numerical analysis of three experiments with temperatures T = 20 °C, 40 °C, 50 °C and 60 °C. The optimal values of the temperature-time analogy coefficients were obtained to develop a methodology for assessing the service life of polymer building structures.