Tensile and long-term creep properties of structurally and functionally integrated carbon fiber reinforced plastic at room temperature

Abstract

Carbon fiber reinforced plastic (CFRP) based on phenolic resin have been widely used in aerospace and pressure vessel fields because of their high stiffness to weight ratio and excellent mechanical properties. In this paper, carbon fiber reinforced plastic were prepared by molding method using phenolic resin as the matrix. The fiber distribution inside the material and its influence on tensile fracture mechanism and creep properties were investigated. The specimens were prepared along horizontal and vertical directions. The test results show that the fibers tend to be distributed horizontally within the material and are influenced by the mold. Horizontal specimens with a large number of fibers parallel to the tensile direction exhibit more excellent tensile properties. The vertical specimen is loaded by the resin and interface with weaker properties inside. The fracture mechanism of horizontal specimens is fiber breakage, fiber pullout and resin fracture, while the fracture mechanism of vertical specimens is interfacial debonding and resin fracture. The difference in tensile fracture mechanism of horizontal and vertical specimens affects the creep properties of CFRP. The creep resistance of fiber is better than that of resin. Therefore, horizontal specimens exhibit better creep resistance in long-term creep tests due to the loads borne by the fibers. Modified Time Hardening model can accurately fit all experimental data. Creep curves can be predicted based on the model parameters.