Experimental/numerical investigation of moisture diffusion in glass/epoxy composites in consideration of interlamination and interphase

Abstract

In order to investigate the influence of the composite interlamination and interphase on the moisture absorption diffusivity, moisture absorption experiments were conducted on both unidirectional glass/epoxy composite and pure epoxy resin and the composite three dimensional diffusivities were obtained. The composite interlamination and interphase were observed by optical microscope and atomic force microscope, separately. Based on the experimental results, the composite transient diffusion finite element (FE) models and steady diffusion FE models were established, taking account of interlamination and interphase. Results show that the composite diffusivity along the fiber direction is larger than that in the direction transverse to the fiber. Diffusivities of the two directions transverse to the fiber were different. FE models with interlamination can more realistically reflect the composite structure and its moisture absorption process. Interlamination promotes diffusion in the direction transverse to fiber and warp affects the diffusivity apparently. The orthotropic interphase properties need to be considered to fit the three dimensional composite diffusivities.

Keywords

• composites
• moisture absorption behavior
• interlamination
• fiber/matrix interphase