s Rahnama - Assistant Professor, Department of Mechanical Engineering, University of Birjand, Birjand, southern Khorasan, Iran
r Gholami - B.S. student, Department of Mechanical Engineering, University of Birjand, Birjand, southern Khorasan, Iran

One of the well-known environmental factors affecting materials properties and as a result the qualification of the device made of is humidity. Specially when they are under one or a series of loads beside the humid environment. The main equations involved in this topic are Fick s law of moisture diffusion and in the present paper, an analogybetween Fick s and Fourier Law which helps modeling the process. In this paper a moisture-deflection analysis for Eglass fiber reinforced with vinyl ester under tension loading is presented. The deformation behavior of the sample sheet under unidirectional tension for different moisture contents is predicted using a FEM software, ABAQUS, based on Fick s law and thermal-moisture analogy. The results suggests that humidity influence mechanical properties of composites for worse.

Moisture diffusion, vinyl ester, Fick s law, thermal-moisture analogy, tension reaction