Temperature effect on mode I fracture toughness of silica/glass/epoxy composites

The mechanical properties of polymer matrix composites, such as fracture toughness, can be affected by the operating temperature. In this study, experimental and computational approaches were used to investigate the effect of temperature on the mode I fracture toughness of a glass/epoxy composite laminate filled with nanosilica particles. Double cantilever beam (DCB) tests were conducted at room temperature, 50 degrees C and 65 degrees C conditions on the glass/epoxy and 0.5 wt.% nanosilica/glass/epoxy composites. The addition of nanosilica to the glass/epoxy composites increased the initiation (Gini) and propagation (Gpro) fracture toughness by 7.3% and 39.5%, respectively, at room temperature. This was due to the enhanced bond strength of the fiber/matrix resulting from the addition of nanosilica. At a test temperature of 65 degrees C, the initiation fracture toughness of the glass/epoxy and the glass/epoxy/ nanosilica increased by 22.4% and 22%, respectively, while the propagation fracture toughness increased by 64% and 28%, respectively. Numerical simulations using Abaqus software on two-dimensional and three-dimensional models confirmed the capability of cohesive zone models to simulate the load-displacement response of the specimens under different thermal conditions. Increasing test temperature increases the fracture toughness of the composite.The fracture toughness of the composite is increased by adding nanosilica.The fiber/resin bonding strength is reduced by increasing the test temperature.Adding nanosilica and increasing temperature enhanced the fiber bridging mechanism.