Análise do comportamento de fluência de compósitos cilíndricos de basalto/epóxi e de vidro/epóxi submetidos a diferentes temperaturas e carregamento hidrostático

Abstract

The present study aimed to evaluate the creep behavior of cylindrical Basalt Fiber Reinforced Polymer made by epoxy resin and of Glass Fiber Reinforced Polymer made by epoxy resin, applied at constant hydrostatic pressure for a period of 500 h at two different temperatures: 22 ºC, considered as room temperature, and 50 °C. The cylinders were manufactured using the filament winding technique, with the matrix curing in an oven at a final temperature of 150 ºC. The mechanical properties were determined through the values of pressure and rupture deformation, as well as the physicochemical properties through thermal assays. The microstructural analyzes were performed using a scanning electron microscope (SEM) and one of the main objectives was to identify the behavior of the fiber/matrix interface. The micrographs also showed excellent homogeneity in the impregnation of the fibers by the matrix. Results of the glass transition temperature (Tg) showed values between 120 and 124 ºC, for the BFRP and GFRP, respectively, indicating a well-controlled curing of the polymeric matrices. Volumetric fiber fractions were obtained by the TGA method and resulted in values of 55% and 57%, respectively, for the BFRP and GFRP, also indicating a high degree of adjustment in the cylinder manufacturing parameters. The maximum creep values measured on the surface of the cylinders at room temperature and at 50 ºC were respectively 1.2% and 1.25% for the BFRP and 0.72% and 0.82% for GFRP. The deformation results in the radial direction (traction) were on average 4 times greater than the values recorded in the longitudinal direction (compression) for both cylinders. BFRP cylinders showed higher creep strain value than GFRP cylinders under the same conditions of hydrostatic loading and time experienced. Thus, it was possible to properly know the mechanical characteristics of deformation and creep of composite materials of FB/epoxy and FV/epoxy.