Analytical models were developed for predicting mechanical properties, moduli and strengths, of unidirectional composites under hygrothermal conditions. The models, based on micro-mechanics, can be used to evaluate the effects of temperature and moisture on the properties of graphite/epoxy unidirectional composites, below the glass transition temper ature. Existing data of AS/3501-5 and T300/976 graphite/epoxy composites were used to compare with the analyses. The comparisons generally agreed very well with the data. Ac cordingly, the models easily could be implemented with existing finite element codes for evaluating the response of laminated composite plates under hygrothermal conditions.
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