Creep properties and damage mechanism of molded glass fiber reinforced plastic

Abstract Glass fiber reinforced plastic (GFRP) has become one of the most commonly used materials in the structure of aero engines in the last decades. In this study, GFRP was fabricated by molding with phenolic resin as the matrix. Specimens were prepared along horizontal and vertical directions. Fiber distribution, tensile properties, long‐term creep performance, and damage mechanism were systematically investigated. Experimental results shows that horizontal specimens have better tensile properties, lower viscoelasticity, and excellent creep resistance. The fibers inside the cylindrical material exhibit a 3D core‐shell morphology with transverse isotropy in the core region. Load is carried by the fibers and the damage is in the form of fiber fracture and pull‐out in horizontal specimens. Random distribution and interweaving leads to double fracture sections of fibers. Load is carried by the interface and resin, and the damage is in the form of fiber pull‐out laterally and interfacial debonding in vertical specimens. High viscoelasticity of the resin and the weak interfacial bonding ability lead to large creep deformation of vertical specimens. In addition, the creep strain under different loads can be accurately predicted by Modified Time Hardening model.