THE COMBINED EFFECTS OF HYGROTHERMAL AND EXTERNAL LOAD ON THEMOISTURE ABSORPTION BEHAVIOR OF E-GLASS/EPOXY COMPOSITES

Abstract

Abstract: This paper investigates the combined effects of hygrothermal and external tensile load on the moisture absorption behavior of E-glass/6509 epoxy composites. Governing equation for hygromechanical coupling diffusion is derived from the theory of irreversible thermodynamics. A new form of Gibbs free energy is introduced using temperature, moisture concentration and the matrix octahedral shear stress as independent state variables. Accelerated moisture absorption experiments in different hygrothermal environments were carried out with a self-made compression spring loading device, and response surface methodology (RSM) was used to establish a surrogate model for predicting the influence of environmental factors on the diffusion coefficient and equilibrium moisture content. The results show that moisture diffusion coefficient and equilibrium moisture absorption of composites increase with the increase of matrix octahedral shear stress. The moisture absorption of composites can be accelerated by increasing temperature, and the equilibrium moisture content can be increased by increasing the relative humidity. The surrogate model obtained by the response surface method can accurately predict the moisture absorption behavior of glass fiber/epoxy composites under the effect of hygromechanical coupling.

Key words: composite, multi-physics coupling, equilibrium moisture content, moisture diffusion coefficient, octahedral shear stress of matrix, Gibbs free energy

CLC Number:

TB332

SUN Tong-sheng, YU Cun-gui, YANG Wen-chao, ZHONG Jian-lin. THE COMBINED EFFECTS OF HYGROTHERMAL AND EXTERNAL LOAD ON THEMOISTURE ABSORPTION BEHAVIOR OF E-GLASS/EPOXY COMPOSITES[J]. Composites Science and Engineering, 2020, 0(5): 25-31.

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